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					LOCAL AREA NETWORK
A local area network (LAN) connects personal computers, printers, and other computer resources together within a building or campus. Many schools, offices, and even homes now have LANs. These networks allow printers, as well as documents and projects, to be shared. LANs also enable computers to talk to one another and are often used to share Internet access across all of the computers in a building or school. Most LANs use wires, or cables, to connect computers and other peripheral devices. In most networks, a network cable (which generally looks like an oversized telephone cord) connects a computer to a network jack in the wall. Sometimes, in classrooms or business offices, many computers are connected to an intermediate hub or switch, not directly to the network jack. The hub or switch into which all of the computers are plugged is the device that is connected to the network jack. In both cases, the network jack is connected to a small router by another cable. Printers are also often shared using this method of hubs and switches. Some LANs are now wireless. Wireless LANs are fundamentally the same as wired LANs, but the cabling is replaced by small "radios" that are contained inside the computers. Wireless LANs are generally somewhat slower than the wired networks, but they are much easier to set up and allow users to move their machines around without having to reconnect network cables. Wireless LANs have moved into the mainstream in schools and classrooms during the last few years; however, it is important to note that security is much more difficult when using a wireless network. Additionally, the adoption of competing protocols is creating some confusion in the marketplace. Agencies need to select a wireless protocol with care, considering how the network can be upgraded and whether it is compatible with existing wireless protocols.
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Where a LAN may connect all of the computers within a building or campus, a wide area network (WAN) connects multiple LANs. Many districts now have WANs connecting all of the schools within the district for the sharing of Internet access, selected files, or other resources.

What Are Servers, Routers, and Firewalls? LANs often involve a number of different components, including a dizzying variety of servers, switches, routers, firewalls, and the like. This section provides descriptions of many of these items. Servers While servers often are spoken of in almost mystical tones, they are really just powerful computers running specialized software designed to share files, manage printers, or perform any other specialized task assigned. Most of these computers are powerful enough to do more than one thing at a time; for example, a single network server might be a file server, a print server, and a mail server simultaneously. File server. A file server is essentially the computer equivalent of a filing cabinet. Documents, spreadsheets, and other (computer) files are stored on a file server, just as paper documents are stored in a filing cabinet. The file server's job is to make those files available to computer users on the LAN and, when appropriate, allow the users to update the files. Print server. A print server is a piece of software or hardware that manages print jobs submitted by users. When a document is sent to a networked printer, the print server receives the job and queues it (puts it in line behind previously submitted jobs). When a job gets to the front of the queue, the print server sends it to the printer. It is not necessary to buy an individual printer for each personal computer. Users in classrooms or offices often share printers, since not everyone is typically

printing at the same time. This option can save an agency a great deal of money. Mail server. The third common type of server is a mail server. The mail server acts as the conduit to the outside world as messages are sent and received. Some servers are set up so that all of the mail stays on the mail server until a user actively deletes it. In other configurations, the user is able to move the mail from the server to the desktop computer. This process, called "downloading," uses less space on the mail server. Router A router is a piece of equipment that acts as the interface between a local network and the Internet, by routing traffic from one to the other. A router may be a
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computer dedicated to managing the traffic of a WAN, or it may be a piece of software running on a computer that is configured for other tasks as well. Routers also may be used in LANs to route internal traffic. Firewall A critical component of any network is a firewall. A firewall in layman's terms is a wall that acts as a firebreak—it keeps a fire from spreading. In this sense, a computer firewall keeps a network secure from hackers (the "arsonists" of the Internet) by denying access to all or part of the network. Management of firewalls requires a great deal of expertise. While the network administrator must ensure that no unwanted traffic can enter the network from outside, a level of access to and from the Internet must be created that will permit authorized users to conduct their business safely and efficiently. A solid, well-designed firewall is critical to ensure that only authorized users have access to a restricted network. Like routers and servers, firewalls are available as either hardware or software. Choosing a firewall for a particular network is an issue best addressed at the local level, after reviewing the options available. Server vs Desktop Computer Advances in technology have blurred the distinctions between the computer on the desktop and a network server. Computing power has continued to grow exponentially—in fact, most users do not need all the computing power available to them (at least for now). The same is true of network servers, which have become so powerful that some network administrators run applications, in addition to the server software, from the network server, rather than installing applications directly on each of the computers connected to the network. Servers are capable of managing a much greater workload today than they were in past years. Running applications from a server has a number of advantages. One key advantage is in licensing, since it is much easier to track usage. Another is that local users are prevented from altering the configuration of applications, which can create software failure and cause problems for other users. In addition, it is much easier to upgrade software since only one copy needs to be upgraded, instead of upgrading one copy for each personal computer. Applications run from a network server, however, are often comparatively slower than applications running directly on a desktop computer. Another benefit to server-run applications is the cost-saving use of thin clients. Thin clients are basic, low-cost computers with insufficient power to run sophisticated software applications, but with enough power to access applications installed on the server. By purchasing a single copy of an application that can run on a network, with
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licenses for multiple users, the organization can save the cost of multiple software copies and can purchase less powerful computers at a much lower cost. In addition, by instituting a thin client environment, older computers in schools have longer useful lives. In recent years, more and more LANs have incorporated thin clients for a variety of purposes. In addition, more and more computer applications are written to take advantage of the web to run remotely. The user's desktop computer essentially acts as a "dumb" terminal, simply displaying the web pages

broadcast by the server. The computing actually takes place on an Internet server, and users transmit their commands via the web page. This web-based model works best when users have high-speed Internet connections. Computing today occurs on the desktop, on network servers, and Internet servers alike. The distinctions between the various types of computers and servers, in many cases, matter less and less. As computer and network transmission speeds improve, the differences will be even harder to grasp. The increasing complexities of computing and networking reinforce the need for agencies to employ the services of a qualified network administrator. Connecting to the Internet There are many different ways to connect to the Internet. Agencies can generally purchase several different kinds of on-ramps to the information superhighway based on their particular need. Depending on the kind of connection to the Internet, access to information may be fast or slow. The key to Internet speed is bandwidth. Bandwidth refers to the amount of data transferred within a specified time. Greater bandwidth increases the speed of data transfer. A general overview of the various types of Internet connections is listed below, starting with the slowest (smallest bandwidth) and moving up to the faster (greater bandwidth) technologies. Cost and service quality can vary widely. Use of a competitive bid process, with an appropriate Request for Proposal (RFP), can better enable agencies to obtain needed service while controlling cost. In other words, the agency should not commit to service from a provider based on advertisements. Acronyms and abbreviations referenced in this appendix are defined in the glossary. A reference table is provided at the end of this appendix for quick comparison of the various Internet connection options discussed below. Internet Service Providers Internet Service Providers (ISPs) provide the portals, or access, that allow computer users to connect to the Internet. There are numerous ways for education agencies to
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connect with an ISP. Before selecting an ISP, the agency should determine its needs for bandwidth, speed, and services. The agency should secure the services of an ISP through the RFP process. Using the RFP process, the ISP should be required to identify the available connection speed and the reliability of the system, sometimes measured by the amount of time the ISP's services were down during the previous 6 months. Although most ISPs will advertise a high connection speed, the agency should determine whether the full bandwidth is available at all times by requesting an assessment of the provider's typical bandwidth and connection speed at different times of the day and on different days of the week. The chief technology officer or technology director should review any ISP proposal. Following are descriptions of the various Internet connections available. Dial-Up Dial-up services connect to the Internet using modems over a traditional telephone line. The vast majority of Internet users connect to the Internet from home via dialup service. The maximum connection speed is 56 kilobits per second (Kbps), which is slow when supporting bandwidth-intensive services, such as video conferencing or streaming video. Dial-up service is typically sufficient for using web and e-mail applications. It is not recommended for multiple users, such as a number of students, who need to access the Internet at the same time. Dial-up service is available almost everywhere in the United States and is the least expensive way of connecting to the Internet/World Wide Web. ISDN Developed and marketed through the 1980s and early 1990s, the Integrated Services Digital Network (ISDN) was the telephone company's first attempt at providing faster online services. As with dial-up service, ISDN is generally insufficient for serving a large number of users with the same connection. The service provides up to 128 Kbps, approximately twice the speed of dial-up. ISDN tends to be much more expensive than

dial-up, costing generally $100 to $300 per month. For the most part, DSL technology has replaced ISDN; however, in some areas where DSL is not available, ISDN may be the best option. If available, most of the other services mentioned in this appendix provide greater capacity at lower cost than ISDN. DSL Digital Subscriber Line (DSL) technologies have largely replaced ISDN service as the product telephone companies want consumers to use when connecting to the Internet. Like dial-up service, DSL connects to the Internet over ordinary copper telephone lines, but is faster-at rates of 1.5 to 6.1 megabits per second (Mbps)enabling continuous transmission of video and audio. DSL service is primarily marketed to home and small business users, but the service is adequate to meet the
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needs of education agencies. While it does not have the same quality of service in terms of speed or support that dedicated fiber optic lines typically provide, DSL is much more affordable. DSL is available in much of the United States, particularly in urban areas. Commercial DSL service generally runs from $100 to $250 per month, but can run significantly higher. DSL service quality can vary from area to area and from service provider to service provider. Additionally, the speed of access to the Internet depends on the distance between the user and the DSL relay station. Cable Modems Cable modems have become, in recent years, the most popular broadband technology for home computer users. The cable modem uses the same coaxial cable that carries cable TV signals for high-speed data transmission. While not as robust as fiber optic connections, cable modems can provide similar quality service at a fraction of the cost. The quality of a cable modem connection, however, is dependent on the overall quality of the cable modem provider's network, and the more people accessing the provider's network at the same time, the slower each individual's connection to the Internet will be. Speed ranges from under 1 to 8 Mbps; costs are generally $100 to $250 per month for commercial users. Because of the historically strong connection between education and the cable television community, many schools are using cable modems. When contracting to provide cable service to a city or county, the cable company typically makes the commitment to provide one cable connection and one modem to each school within the service area of the cable company. There are cases, however, in which cable companies have provided additional services. Higher Bandwidth Connections (including fiber optics) Many businesses and schools today connect to the Internet through larger cables, typically referred to as T1 (copper wire), T3 (coaxial cable or fiber optic cable), or OC3c (fiber optic) connections. These services are widely available, are highly flexible, and provide high quality, fast broadband service. Costs are comparatively high and vary widely from area to area. In urban areas, T1 connections (providing 1.5 Mbps) are generally available for approximately $200 to $500 per month. In rural areas, the same connection usually costs much more. Larger T3 and OC3c connections, which provide 45 Mbps and 155 Mbps, respectively, generally cost several thousands of dollars per month in urban areas and tens of thousands of dollars per month in rural areas. Depending on the bandwidth needs of the school or district, it may be more sensible to utilize a less expensive connection. For some agencies, a more feasible option in the T-carrier system may be a "fractional" T1 line, which utilizes a portion of the T1. Fractional T1 lines are
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available to meet almost any speed requirement for a reduced price. This option makes sense for those agencies that may not need a full T1 line today, but might need increased bandwidth in the future. In addition, upgrading fractional T1 to use more of the T1 line can usually be done without purchasing new hardware.

Larger organizations, such as state government agencies or large school districts, may require the faster OC3c connection. These high-speed connections are not always available and, as mentioned, can cost tens of thousands of dollars per month. Where these networks exist, however, states (or counties or large districts) may be able to divide the bandwidth, according to the needs of smaller districts or schools. By doing this, the cost of connecting to the Internet could be reduced for smaller agencies or schools. Districts or schools should, when considering which kind of connectivity to purchase, determine if there is a preexisting network to which they can connect. Satellite Some larger agencies have considered buying space on a satellite to upload and download files. While the cost of transmitting information over wires would be removed, satellite reliability is debatable. Weather (such as rain) or even sunspots can affect satellite transmission. Cellular Wireless Traditionally, Internet access over cellular telephone networks has been slow and somewhat unreliable. Wireless technology, however, is coming of age, and new, significantly faster Internet connection services are offered throughout the United States. While these "third generation wireless" services (generally referred to as 3G services) are not necessarily suitable for building use, they may suit the needs of individuals within the agency as they maintain contact with each other during the workday. Already, cellular phones are replacing "walkie-talkies" in many secondary schools. It is still too soon to tell how much these services will cost, but they will probably be metered, with cost depending upon the amount of usage. Fixed Wireless Fixed wireless refers to the operation of wireless devices in a fixed location. Unlike mobile wireless devices, which are battery powered, fixed wireless devices are electrically powered. The basic idea behind fixed wireless is that the traditional wired connection (e.g., fiber optic, telephone line, or cable TV line) is replaced by a highspeed wireless connection. Depending on the technology, bad weather (such as rain) can significantly interfere with fixed wireless services. This service is usually most attractive in communities where traditional wired connections are not available; however, the technology is also suitable for urban areas. Fixed wireless speed varies considerably, from under 1 Mbps to upwards of 15 Mbps. Cost also varies widely.

Wide-Area Networking Overview
Cisco IOS software provides a range of wide-area networking capabilities to fit almost every network environment need. Cisco offers cell relay via the Switched Multimegabit Data Service (SMDS), circuit switching via ISDN, packet switching via Frame Relay, and the benefits of both circuit and packet switching via Asynchronous Transfer Mode (ATM). LAN emulation (LANE) provides connectivity between ATM and other LAN types. Refer to the Cisco IOS Dial Technologies Configuration Guide: Volume 1 of 2 for further information on configuring ISDN. Refer to the Cisco IOS Switching Services Configuration Guide for information on configuring LANE.

Objectives
The Cisco IOS Wide-Area Networking Configuration Guide presents a set of general guidelines for configuring the following software components: • ATM • Broadband Access: PPP and Routed Bridge Encapsulation • Frame Relay • Frame Relay-ATM Internetworking • SMDS • Link Access Procedure, Balanced and X.25 This overview chapter gives a high-level description of each technology. For specific configuration information, see the appropriate chapter in this document.

Organization
The Cisco IOS Wide-Area Networking Configuration Guide includes the following chapters: • Configuring ATM • Configuring Broadband Access: PPP and Routed Bridge Encapsulation • Configuring Frame Relay • Configuring Frame Relay-ATM Interworking • Configuring SMDS • Configuring X.25 and LAPB

Introduction to NETWORKING
Network is the method to share hardware resources and software resources. We can share the resources with the help of operating system like windows, Linux, UNIX etc. To connect multiple networks we have to use internetworking devices like router, bridge, layer 3, switches etc.

Administrator model for Networks
We can say that there are four components which are required to create networks 1. Software 2. Protocol Stack 3. Network Interface Card 4. Media

Software

Networking software can be divided in two categories: Server software: - The software used to provide a particular service. Client software: - The software which is used to access service provided by server. Server Software Apache, IIS, Exchange 2003, FTP Server, Send Mail Client Software Internet Explorer, Outlook Express, Yahoo messenger, Cute FTP

P

P

TCP/IP, IPX/SPX, AppleTalk, Netbeui

NIC

NIC

Design Considerations Server software and Client software should be compatible. Protocol stack must be same. Connectivity can be performed via switch/hub etc. If NIC standards are different then translational bridge is required. If media is different then Trans-Receiver is required.

OSI Model OSI model is the layer approach to design, develop and implement networks. OSI model provides following advantages: (i) Designing of network will be standards based. (ii) Development time of new technologies will be reduced. (iii) Devices from multiple vendors can communicate with each other. (iv) Implementation and troubleshooting of network will be easier.

 Application Layer: -sales man
Application layer accepts data and forward into the protocol stack. It creates user interface between application software and protocol stack.

 Presentation Layer: This layer decides presentation format of the data. It also able to performs other function like compression/decompression and encryption/decryption. Jpg file Online song

 Session Layer: This layer initiate, maintain and terminate sessions between different applications. Due to this layer multiple application software can be executed at the same time. Telephone trun

 Transport Layer: Transport layer is responsible for connection oriented and connection less communication. Transport layer also performs other functions like Positive Acknowledgement & Response Error checking Flow Control Buffering Windowing Multiplexing Sequencing Connection Oriented Communication

Connection less Communication

Sender Send

Receiver

(i) Error checking Transport layer generates cyclic redundancy check (CRC) and forward the CRC value to destination along with data. The other end will generate CRC according to data and match the CRC value with received value. If both are same, then data is accepted otherwise discarded. (ii) Flow Control Flow control is used to control the flow of data during communication. For this purpose following methods are used: (a) Buffering Buffer is the temporary storage area. All the data is stored in the buffer memory and when communication ability is available the data is forward to another. (b) Windowing Windowing is the maximum amounts of the data that can be send to destination without receiving Acknowledgement. It is limit for buffer to send data without getting Acknowledgement. (c) Multiplexing

Multiplexing is used for multiple application on same IP. (iii) Sequencing Transport layer add sequence number to data, so that out of sequence data can be detected and rearranged in proper manner. (iv) Positive Acknowledgement and Response When data is send to destination, the destination will reply with Acknowledgement to indicate the positive reception of data. If Acknowledgement is not received within a specified time then the data is resend from buffer memory.

Network Layer
This layer performs function like logical addressing and path determination. Each networking device has a physical address that is MAC address. But logical addressing is easier to communicate on large size network. Its other responsibilities are: Fragmentation Header checksum Quality of Service Protocol Identification

Logical addressing defines network address and host address. This type of addressing is used to simplify implementation of large network. Some examples of logical addressing are: - IP addresses, IPX addresses etc. Path determination Network layer has different routing protocols like RIP, EIGRP, BGP, and ARP etc. to perform the path determination for different routing protocol.

Data Link Layer
The functions of Data Link layer are divided into two sub layers  Logical Link Control  Media Access Control   Logical Link Control defines the encapsulation that will be used by the NIC to delivered data to destination. Some examples of Logical Link Control are ARPA (Ethernet), 802.11 wi-fi. Media Access Control defines methods to access the shared media and establish the identity with the help of MAC address. Some examples of Media Access Control are CSMA/CD, Token Passing. Physical Layer is responsible to communicate bits over the media this layer deals with the standard defined for media and signals. This layer may also perform modulation and demodulation as required.

Physical Layer

Data Encapsulation

Data => Segment => Packet => Frames => Bits

Devices at different Layers
Physical Layer Devices Data Link Layer
Hub, Modem, Media, DCE (Data comm. Equipment) CSU/DSU, Repeater, Media converter NIC, Switch, Bridge

Network Layer Device
Router, Layer 3 Switch

All Layers Device
PC, Firewall

DCE: - DCE convert the bits into signal & send them on media.
FDDI – Fiber Distributed Data Interface Switch forwards frames on the base of MAC address. Router forwards packets on the base of IP address.

LAN Technologies
LAN

Ethernet 10 – 10000 mbps

Token Ring 4 – 16 mbps

FDDI 4 – 16 mbps

Wi-Fi 1 – 108 mbps

Ethernet

Ethernet is the most popular LAN technology. It can support verity of media like copper (UTP, Coaxial, fiber optic). This technology supports wide range of speed from 10mbps to 10000 mbps.

Ethernet at Logical Link Control
To create logical link control Ethernet uses ARPA protocol also called IEEE802.3. Ethernet adds source MAC, destination MAC, error checking information and some other information to data. Ethernet encapsulation explain as follows

Ethernet frame
Preamble An alternating 1,0 pattern provides a 5MHz clock at the start of each packet, which allows the receiving devices to lock the incoming bit stream. Start Frame Delimiter (SFD)/Synch The preamble is seven octets and the SFD is one octet (synch). The SFD is 10101011, where the last pair of 1s allows the receiver to come into the alternating 1,0 pattern somewhere in the middle and still sync up and detect the beginning of the data. Length or type 802.3 uses a length field, but the Ethernet frame uses a type field to identify the network layer protocol. 802.3 cannot identify the upper-layer protocol and must be used with a proprietary LAN-IPX, for example

Ethernet at Media Access Control

Ethernet at Media Access Control layer uses CSMA/CD protocol to access the shared media. In these days, we use Ethernet with switches and in switches the technology is made CSMA/CA (Collision Avoidance). So this reason Ethernet is best compare with Token Ring, FDDI & Wi-Fi. CSMA/CD

This algorithm runs when a collision created. Detect the Collision

Stop transmitting receiving data

Generate a random Number

Try to communicate after delay in multiple of random no.

Ethernet Family
Speed 10 10 10 10/100(present) 100 100 1000(Server) 1000 10000 Base band Base 2 Base 5 Base T Base TX Base T4 Base FX Base TX Base FX Base FX 200-meter 500-meter 100 meter 100 meter 100 meter up to 4 kms 100 meter up to 100 kms Coaxial cable Thick Coaxial cable Twisted Pair (UTP) UTP UTP 4 Pairs used Fiber Optic UTP Fiber Optic Fiber Optic

Ethernet Cabling
Coaxial cabling T connector, Terminator, BNC connector, Coaxial cable, 10 base2 lan cards

UTP Cabling In the UTP, we have used different topology to create the network.

In any Ethernet UTP topology we have to use one of the two types of cables  Straight cable  Cross cable Structure Cabling Requirement: Rack, patch panel, Switch/ Hub( Rack Mounable), patch cord, I/O connector, I/O box, UTP cable Tool: - Punching tool

Problems of Ethernet technology
    In Ethernet only one pc is able to send data at a time, due to this the bandwidth of Ethernet will be shared. Not an equal access technology. One pc will send data, which will be received by the all devices of network. Due to this data communication will not be secured. Collision will occur in the network and collision will lead to other problems like latency, delay and reduce throughput. Latency – time duration to send packet from start to end. Throughput – speed to send data (output) All PCs will have single broadcast domain. Due to this the bandwidth will be reduced.



LAN Segmentation of Ethernet Network
There are three methods to perform LAN segmentation (1) LAN segmentation using bridge. (2) LAN segmentation using switches. (3) LAN segmentation using Routers.

LAN segmentation using bridge.
Existing

New

1st collision domain

2nd collision domain

3rd collision domain

1 broadcast domain Working of Bridge: Working of Bridge explains in following steps: (i) Bridge can receives a frame in the buffer memory. (ii) The source MAC address of frame this stored to the bridging table. Port number MAC address 1 2 3 (iii) According to the destination MAC address the frame will be forwarded or drop (a) If destination MAC address of the frame is known then frame is forwarded to the particular port. (b) If destination MAC address is unknown by bridging table then frame is forwarded to the all port except receiving port. (c) If destination MAC address is broadcast MAC address ff.ff.ff.ff.ff.ff. (d) If destination MAC address exist on the same port from which port received then frame is dropped. Collision domain A group of pc, in which collision can occur, is called a collision domain. Broadcast domain A group of pc in which broadcast message is delivered is called broadcast domain.

LAN segmentation using Switches
Due to perform Lan segmentation using switches. We have to remove hubs from the network and replace hub with switches the working of switches. The working of switch is exactly like a bridge. A multiport bridge can be used as a bridge.

1 Broadcast domain

Multiple Collision domain = micro segmentation

Switch‟s working is similar to the bridge. Advantages of Switches: (1) Bandwidth will not be shared and overall throughput will depend on wire speed of the switch. Wire speed is also called switching capacity measured in mbps or gbps. Minimum port on switches = 4 Maximum port on switches = 48 (2) Any time access technology. (3) One to one communication so that network will be more secures. (4) Switches will perform micro segmentation and no collision will occur in network.

Lan segmentation using router
If we are facing high concession in the n/w due to the large number of broadcast then we can divide broadcast domain of network. So that number of broadcast message will be reduced.

1st Broadcast Domain 2nd Broadcast Domain 3rd Broadcast Domain We have to install router between multiple switches to divide the broadcast domain. Each broadcast domain has to used different network address and router will provide inter network communication between them.

Router Administration

In this chapter we will study hardware architecture, Router Booting behavior, Command Line Usage and administration.

Pc Architecture
Processor Memory controller I/O Controller RAM BIOS ROM HDD CMOS RAM FD CDD Sound Card Serial Parallel USB Display Card V.D.U K/B Controller Keyboard

Router Architecture
Processor I/O Controller Memory Controller RAM Ports BIOS ROM NVRAM LAN

WAN

Flash RAM O/S IOS

Components of ROUTER Router operation
When a pc has to send data to a different network address, then data will be forwarded to the router. It will analysis IP address of the data and obtain a route from the routing table. According to the route data will be dropped, If route not available. (1) Processor Speed: - 20 MHz to 1GHz Architecture: - RISC Reduce Instruction set computer Manufacturers: - Motorola, IBM, Power PC, Texas, Dallis, Intel. (2) Flash RAM Flash Ram is the permanent read/write memory. This memory is used to store one or more copies of router o/s. Router o/s is also called IOS (Internetwork Operating System).  Flash Ram stores the only o/s.

The size of flash ram in the router is 4mb to 128mb. The flash ram may be available in one of the following three packages: SIMM Flash: - Single In-Line Memory Module PCMCIA Flash: - Personal Computer Memory Card Interface Architecture Compact Flash: - (Small Memory) (3) NVRAM NVRAM is a “Non Volatile Random Access Memory”. It is used to store the configuration of the Router. The size of NVRAM is 8 KB to 512 KB. (4) RAM Ram of the router is divided into two logical parts. (i) Primary RAM (ii) Shared RAM Primary RAM Primary RAM is used for: (a) Running copy of IOS. (b) Running configuration (c) Routing table (d) ARP table (IP address to MAC address) (e) Processor & other data structure Shared RAM Shared RAM is used as a buffer memory to shared the data received from different interfaces. Size of ram in a router may vary from 2 mb to 512 mb. The types of memory that may be present in a ram are: (a) DRAM Dynamic RAM (b) EDORAM Extended Data Out RAM (c) SDRAM Synchronous Dynamic RAM (5) BIOS ROM The BIOS ROM is the permanent ROM. This memory is used to store following program & Routines: (i) Boot strap loader (doing booting) (ii) Power on self test routines (iii) Incomplete IOS (iv) ROM Monitor (ROM-MON) Router & PC terms Router ROM-MON Incomplete IOS FLASH PC CMOS Setup Bootable Floppy/CD O/S From HDD

Router Interfaces & Ports
Interface is used to connect LAN networks or wan networks to the router. Interface will use protocol stacks to send/receive data. Ports are used for the configuration of routers. Ports are not used to connect different networks. The primary purpose of port is the management of router. Router Interfaces Interface Connector Ethernet RJ45 AUI DB15 color yellow yellow Speed 10 mbps 10 mbps Use To connect Ethernet LAN Using UTP media To connect Ethernet LAN

Using Trans-Receiver Fast Ethernet Serial RJ45 DB60 yellow blue 100 mbps E1-2 mbps T1-1.5 mbps “ 192 kbps To connect Ethernet LAN To connect WAN Technology like Leased Lines, Radio link, Frame Relay, X.25, ATM “ To connect ISDN Basic Rate Interface to connect Phones, Fax, EPABX

Smart Serial BRI ISDN VOIP

SS RJ45 RJ11

blue orange white

AUI – Attachment Unit Interface EPABX – Electronic Private Automatic Branch PSTN – Public Services Telephone Network Router Ports Port Console Auxiliary Connector RJ45 RJ45 Color sky blue black Speed 9600bps depend on Modem Details Used for configuration using PC To connect remote router using PSTN line To connect remote router with telnet protocol via interface 4/16 mbps To connect Token Ring network.

Virtual terminal Vty

Other interfaces:(1) Token Ring (2) E1/T1 controller RJ45 RJ45 Violet White

E1-2048 kbps Connect E1/T1lines T1-1544 kbps UP- 1 mbps For ADSL Broadband Down- 8 mbps

(3) ADSL RJ11 (Asynchronous Digital Subscriber Line)

Types of routers:(1) Fixed configuration router (2) Modular router (3) Chassis based router

Access Router using console
Connect PC serial port to router Console using console cable.

Step 1 Click the Start button on the Windows Taskbar, and select Programs > Accessories > Communications > HyperTerminal. HyperTerminal launches and displays the Connection Description dialog box.Type any name Step 2 Select com port Step 3 On the Port Settings tab, enter the following settings:
    

Speed - 9600 Data Bits - 8 Parity - none Stop bits - 1 Flow Control - none

Step 4 Click ok

Router Access Modes
When we access router command prompt the router will display different modes. According to the modes, privileges and rights are assigned to the user. User mode In this mode, we can display basic parameter and status of the router we can test connectivity and perform telnet to other devices. In this mode we are not configure to manage & configure router. Privileged mode In this mode, we can display all information, configuration, perform administration task, debugging, testing and connectivity with other devices. We are not able to perform here configuration editing of the router. The command to enter in this mode is „enable‟. We have to enter enable password or enable secret password to enter in this mode. Enable secret has more priority than enable password. If both passwords are configured then only enable secret will work. Global configuration This mode is used for the configuration of global parameters in the router. Global parameters applied to the entire router. The command enter in this mode is „configure terminal‟. For e.g: - router hostname or access list of router Line configuration mode This mode is used to configure lines like console, vty and auxiliary. There are main types of line that are configured. (i) Console router(config)#line console 0 (ii) Auxiliary

router(config)#line aux 0 (iii) Telnet or vty router(config)#line vty 0 4 Interface configuration mode This mode is used to configure router interfaces. For e.g:- Ethernet, Serial, BRI etc. Router(config)#interface <type> <number> e.g. Router(config)#interface serial 1 Routing configuration mode This mode is used to configure routing protocol like RIP, EIGRP, OSPF etc. Router(config)#router <protocol> [<option>] Router(config)#router rip Router(config)#router eigrp 10

Configuring Passwords
There are five types of password available in a router (1) Console Password router#configure terminal router(config)#line console 0 router(config-line)#password <word> router(config-line)#login router(config-line)#exit (2) Vty Password router#configure terminal router(config)#line vty 0 4 router(config-line)#password <word> router(config-line)#login router(config-line)#exit (3) Auxiliary Password router#configure terminal router(config)#line Aux 0 router(config-line)#password <word> router(config-line)#login router(config-line)#exit (4) Enable Password router>enable router#configure terminal router(config)#enable password <word> router(config)#exit

(5) Enable Secret Password Enable Password is the clear text password. It is stored as clear text in configuration where as enable secret password is the encrypted password with MD5 (Media Digest 5) algorithm. Router#configure terminal Router(config)#enable secret <word> Router(config)#exit Encryption all passwords All passwords other than enable secret password are clear text password. We can encrypt all passwords using level 7 algorithm. The command to encrypt all passwords are: Router#configure terminal Router(config)#service password-encryption TIP: In CISCO router any configuration can be removed by using „no‟ prefix to the same command.

Managing Configuration
There are two types of configurations present in a router (1) Startup Configuration (2) Running Configuration Startup configuration is stored in the NVRAM. Startup configuration is used to save settings in a router. Startup configuration is loaded at the time of booting in to the Primary RAM. Running Configuration is present in the Primary RAM wherever we run a command for configuration, this command is written in the running configuration. To display running-configuration Router#show running-configuration To display startup configuration Router#show startup-configuration To erase old configuration Router#erase startup-configuration Router#reload Save[y/n]:n To save configuration Router#copy running-config startup-config Or Router#write To abort configuration Router#copy startup-config running-config

CISCO command line editing & shortcuts Command line shortcuts
Tab – to auto complete command ? – To take help Ctrl+P – to recall previous command Ctrl+N – next command Ctrl+Z – alternate to „end‟ command Ctrl+C – to abort Q – to quit Ctrl+Shift+6 – to break connection

Command line editing shortcuts
Ctrl+A – to move cursor at start of line Ctrl+E – to move cursor at end of line Ctrl+ B – to move cursor one character back Ctrl+F – to move cursor one character forward Ctrl+W – to delete word one by one word back Ctrl+D – to delete one character Ctrl+U – to delete one line Esc+B – to take cursor one word back Esc+F – to take cursor one word forward

Configuring HostName Configuration Interfaces
Router#configure terminal Router#hostname <name>

Interfaces configuration is one of the most important part of the router configuration. By default, all interfaces of Cisco router are in disabled mode. We have to use different commands as our requirement to enable and configure the interface. Configuring IP, Mask and Enabling the Interface Router#configure terminal Router(config)#interface <type> <no> Router(config-if)#ip address <ip> <mask> Router(config-if)#no shutdown Router(config-if)#exit Interface Numbers Interface numbers start from 0 for each type of interface some routers will directly used interface number while other router will use slot no/port no addressing technique. Eth 0 Serial 0 Serial 1 Slot 1 Serial 1/0 Serial 1/1 Slot 0 Serial 0/0

To configure Interface description Router#configure terminal Router(config)#interface <type> <no> Router(config-if)#description <line> Configuring parameters on LAN interface Router#configure terminal Router(config)#interface <type> <no> Router(config-if)#duplex <half|full|auto> Router(config-if)#speed <10|100|auto> Router(config-if)#end

Configuring parameters on WAN interface Router#configure terminal Router(config)#interfac <type> <no> Router(config-if)#encapsulation <protocol> Router(config-if)#clock rate <value> Router(config-if)#end To display interface status Router#show interfaces (to show all interfaces) Router#show interface <type> <no>

Show interfaces command will display following parameters about an interface
Status Mac address IP address Subnet mask Hardware type / manufacturer Bandwidth Reliability Delay Load ( Tx load Rx load) Encapsulation ARP type (if applicable) Keep alive Queuing strategy Input queue detail Output queue details Traffic rate (In packet per second,bit per second) Input packet details Output packet details Modem signals (wan interface only) M.T.U maximum transmission rate (mostly 1500 bytes)

Configuring sub interface Sub interface are required in different scenario. For e.g:- in Ethernet we need sub interface for Vlan communication and in frame relay we need sub interface for multipoint connectivity. Sub interface means creating a logical interface from physical interface. Router#config ter Router(config)#interface <type> <no>.<subint no> Router(config-subif)# Router(config)#interface serial 0.2 Configuring secondary IP Router(config-if)#IP address 192.168.10.5 255.255.255.0 Router(config-if)#IP address 192.168.10.18 255.255.255.0 secondary

Managing Command Line History
We can use CTRL+P & CTRL+N shortcuts to display command history. By default router will up to 10 commands. In the command line history, we can use following commands to edit this setting To display commands present in history Router#show history To display history size Router#show terminal To change history size Router#config terminal Router(config)#line console 0 Router(config-if)#history size <value> Router(config-if)#exit

Configuring Banners
Banners are just a message that can appear at different prompts according to the type. Different banners are: Message of the day (motd)-This banner appear at every access method

Login-Appear before login prompt Exec- Appear after we enter to the execution mode Incoming-Appear for incoming connections Syntax:Router#config terminal Router(config)#banner <type> <delim. char> Text Massage <delimation char> Router(config)# Example:Router#config terminal Router(config)#banner motd $ This router is distribution 3600 router connected to Reliance $ Router(config)#

Logging configuration
Router generates the log message, which has stored in the router internal buffer and also displayed on the console. To send log messages to sys log server Router#config ter Router(config)#logging <IP address> Router(config)#exit To display log buffer Router#show logging Synchronous Logging on console Router#config terminal Router(config)#line console 0 Router(config)#logging synchronous Router(config)#exit

Download Syslog Server Software from internet & install it on PC to store syslog messages.

Configuring Router Clock

We can configure router clock with the help of two methods. (1) Configure clock locally (2) Configure clock on NTP server (Network Time Protocol) Router does not have battery to save the clock setting. So that clock will reset to the default on reboot. In new routers clock battery will be available for time keeping. To display clock Router#show clock To configure clock Router#clock set hh:mm:ss day month year Use “C:\>ping pool.ntp.org” To configure clock from NTP server Router#config terminal Router(config)#ntp server <IP address> Router(config)#exit

To get ntp server ip from internet

Status message of Interfaces
When we use “Show Interfaces” command on router. The first two lines will display the status message. It will display one of the following four messages. Interface is administratively down, line protocol is down. This message means that the interface is shutdown by the administrator using “shutdown” command. We can change this status with help of “no shutdown” command. Interface is up, line protocol is up. This message will appear when everything working fine and interface is able to communicate with other devices. In case of Ethernet, this message will display when interface is connected and enabled. In case of serial, this message will display when end to end connectivity is established. Interface is down, line protocol is down In case of serial, this message will appear due to loss in connectivity with modem. Interface is up, line protocol is down This message will appear due to the encapsulation failure. In case of Ethernet, this message may appear when interface is not connected properly. In case of serial, this message may appear due connectivity problem with far end router.

Setup Mode
The router will enter in setup mode if there is no configuration is present in NVRAM. The router will display following message “Would you like to enter in initial configuration dialog [ y / n ]: “ There are two types of setup modes:  Basic setup mode  Extended setup mode In basic mode only one interface is configured which will be used for telnet or web access connectivity. In extended mode all interfaces are configured. At the end we can save configuration changes or discard changes

Telnet access :
Telnet is a virtual port through which we can access router command line using interfaces

PC

Switch

Router

To accept telnet connection we have to configure following options on router: Configure IP on interface Configure VTY, enable secret password On client PC test connectivity with router & use command ‘telnet <router_ip>’

SSH access to Router or Switch
There are four steps required to enable SSH support on an IOS router: 1. Configure the hostname, domain name command. 2. Generate the SSH key to be used. 3. Enable SSH transport support for the virtual type terminal (vtys). 4. 5.

Router Booting Sources A router can boot from various sources. By default, it will boot from the flash memory and we can control the sequence with the help of configuration system or commands. A router can boot from following sources: (1) First file in flash (2) Specific file in flash (3) Incomplete IOS (4) TFTP Server (5) Rom Monitor (from Bios) The first to control boot sequence using configuration system register. We can modify configuration register value with the help of “config-register” command in global configuration mode. We can also modify register value from ROM monitor mode. Configuration Register Configuration Register is 16-bit value, which is stored in the NVRAM. At the time of booting the Bootstrap Loader reads the value of configuration Register and according to the value it configure its booting behavior. 0x2102 (IOS with Config) With this value the router will boot from first file present in the flash memory. This is the default value of configuration register. After loading IOS the router will also load startup-config into running-config. 0x2101 (Incomplete IOS with Config) The router will boot from incomplete IOS and then load the startup-config. 0x2100 (Rom Monitor) With this router will not boot, but enters in the Rom Monitor mode. 0x2142 (IOS without Config) The router will boot from first file in flash. But bypass the startup configuration 0x2141 (Incomplete IOS without Config) The router will boot from Incomplete IOS but bypass the startup-config. To change Config-Register from global mode Router#configure terminal Router(config)#config-register <value> Router(config)#exit Router#reload Note: - this is the only value, which is configured in the configuration mode and does not need to be saved. To change Config-Register using Rom Monitor Steps: (1) Power on the router (2) Press “ctrl+break” from console with in 60 sec. (3) The router will enter to the Rom Monitor. Type following commands Rommon 1> confreg <value> Rommon 2> i Note: - in 2500 series router “o/r” command should be used in place of “confreg” command.

Boot System commands

Boot system command is the second method to control sequence of router. These commands will be executed only when configuration register is set to 0x2102. Boot system commands are executed in global configuration mode. These commands are executed in the same sequence they are applied to the router. If one boot system command is successful then next boot system command is not executed in the router.

TFTP server

To boot router from specific file in flash Router(config)#boot system flash <file name>

To boot from first file in flash Router(config)#boot system flash

TFTP server is TFTP server/network file without performing To boot router frommodified form of FTP. It is used to transfer To boot from incomplete IOS authentication. TFTP has only tftp <file name>in which subdirectories are not allowed. Directory home directory, <IP address> Router(config)#boot system Router(config)#boot system rom browsing is not allowed in the home directory. TFTP is the udp-based protocol, which works on port no 69. TFTP has following features in comparison to the FTP. (1) Only get file and put file service is available. (2) Authentication is not supported. (3) Home directory may not have subdirectories (4) Directory browsing is not allowed Installation and Configuration of TFTP server In windows system, we have to execute following steps to use the pc as TFTP server. (1) Download TFTP server software from Internet. (2) Install the TFTP server software on pc. (3) If software is not installed as the service then software should be running on screen. Configure home directory of server or use default. Functions to be perform with the help of TFTP server (1) To boot router from TFTP server (2) Backup IOS and configuration (3) Restore IOS and configuration (4) Upgrade IOS (1) To boot from TFTP server i) Run the tftp server s/w on pc. And copy IOS image file in the Home directory of tftp server. ii) Test connectivity between router and tftp server. iii) On router use following commands:Router#conf ter Router(config)#boot system tftp c1700-1s-mz.122.3.bin 10.0.0.18 Router(config)#exit Router#copy runn start Reload the device. Make sure that configuration register set as 0x2102. 2) To backup IOS i) Test connectivity and make sure TFTP server is running. ii) Type command: Router#show flash (note the IOS filename) Router#copy flash TFTP Source filename = ? Destination filename=? IP of TFTP server=? (3) To backup Configuration i) Test connectivity and make sure TFTP server is running. ii) Type commands: Router#copy running-config tftp Or Router#copy startup-config tftp Remote IP: ________ Destination Filename: ________

3) To restore Configuration i) Test connectivity and make sure TFTP server is running. ii) Make sure configuration file is present in home directory and note the filename. iii) Type commands: Router#copy tftp running-config Remote IP: __________ Source Filename: ___________ Destination Filename[running-config]: _ Press enter here 4) Restore/Upgrade IOS There are four different conditions in which we can restore/upgrade IOS. Case 1: old IOS is present and flash is in read/write mode.  Copy IOS image in tftp server‟s home directory.  Test connectivity and make sure tftp server is running.  On router use commands: Router# copy tftp flash Source file: Destination file: IP address: Erase Flash [y/n]: Case2: Old IOS is present but flash is in read only mode.  In this case, we have to set config-register to 0x2101 to boot the router from incomplete IOS.  After booting the flash will be read/write mode. Now use same command as in condition case 1.  When IOS loading is complete reset config-register to 0x2102. Case3: old IOS is not present but incomplete IOS is present in bios. The router will automatically boot from incomplete IOS. And we have to execute same commands as in case1 and case2. Case4: Complete IOS and incomplete IOS is not present in router. There are two methods to load IOS with the help of Rom Monitor mode. Method1: Loading IOS using xmodem In this case we have to use xmodem command and the IOS will be loaded with the help of console cable. Tftp is not required in this case.  Enter to the Rom Monitor and type following command. Rom Mon 1>xmodem <filename>  When router display a message “ Ready to receive file” then click on HyperTerminal then Transfer>> Send file>> use browse to select file>> select protocol xmodem>> send. Method2: In this case we have to use tftp server in Rom Monitor.  Connect the pc tftp server make sure tftp is running and IOS image present in the home directory.  Enter to the Rom Monitor mode and type following command. Rom Mon>IP_ADDRESS=10.0.0.2 Rom Mon> TFTP_SERVER=10.0.0.1 Rom Mon> TFTP_FILE=<filename> Rom Mon> DEFAULT_GATEWAY=10.0.0.1 Rom Mon> IP_SUBNET_MASK=255.0.0.0 Rom Mon> tftpdnld When IOS transfer is completed then type command. Rom Mon>boot

To view source from which router boots. Router#show version

Resolving Host Names
In router, we can communicate with the help of IP address as well as host name and domain name. There are two methods to resolve hostname into IP address. 1) Using local hostname database We can use local hostname database by using IP host command. We can use this command with following syntax: To create local hostname database Router(config)#IP host <name> <IP address> To display hosts Router#show hosts

2) Using a DNS server We can configure router to send DNS queries to DNS server. The DNS server will resolve hostname and then pc or router will try to communicate with destination. We can create maximum 6 IP. Router#config terminal Router(config)#IP name-server <IP> [<IP2>] Router(config)#IP name-server 202.56.230.6 Router(config)#exit

Managing Telnet connection
Our router is able to telnet other devices as well as other devices can also perform telnet to our router. To allow Telnet access to router For this purpose we have to configure IP address, vty password and enable secret password. IP must exist between client and router. When router will be able to perform telnet access. On telnet client we have to use following command: Router#Telnet <IP of router> To display connected users Router#show users To disconnect a user Router#clear line <no> To display connected session Router#show sessions To telnet a device from router Router#telnet <IP> To exit from telnet session Router#exit To exit from a hanged telnet session Ctrl+shft+6 X Router#disconnect

TIP: If we want to allow telnet router without password then on the VTY type command “No Login”.

TCP/IP MODEL
TCP/IP is the most popular protocol stack, which consist of large no of protocol. According to the OSI model TCP/IP consist of only four layers. TCP/IP model is modified form of DOD (Department of Defense) model.

Application Layer
This layer contains a large no. of protocols. Each protocol is designed to act as server & client. Some of protocol will need connection oriented. TCP and others may need connection less UDP for data transfer. Application layer use port no.s to identity each application at Transport layer. This layer performs most of functions, which are specified by the Application, Presentation, and Session layer of OSI model.

Transport Layer
Two protocols are available on Transport layer Transmission Control Protocol User Datagram Protocol 1) Transmission Control Protocol: TCP performs connection-oriented communication. Its responsibilities are: Error Checking Acknowledgement Sequencing Flow Control Windowing





   

Source Port and Destination Port fields together identify the two local end points of the particular connection. A port plus its hosts’ IP address forms a unique end point. Ports are used to communicate with the upper layer and distinguish different application sessions on the host. The Sequence Number and Acknowledgment Number fields specify bytes in the byte stream. The sequence number is used for segment differentiation and is useful for reordering or retransmitting lost segments. The Acknowledgment number is set to the next segment expected. Data offset or TCP header length indicates how many 4-byte words are contained in the TCP header. The Window field indicates how many bytes can be transmitted before an acknowledgment is received. The Checksum field is used to provide extra reliability and security to the TCP segment. The actual user data are included after the end of the header.

2) User Datagram Protocol UDP is considered to be a connectionless protocol. It leaves reliability to be handled by the application layer. All it cares about is fast transmission. UDP header is responsible for error checking and identifying applications using port numbers.

Internet Layer
The main function of Internet layer is routing and providing a single network interface to the upper layers protocols. Upper or lower protocols have not any functions relating to routing. To prevent this, IP provides one single network interface for the upper layer protocols. After that it is the job of IP and the

various Network Access protocols to get along and work together. The main protocols are used in Internet layer:1) Internet Protocol (IP) 2) Internet Control Message Protocol (ICMP) 3) Address Resolution Protocol (ARP) 4) Reverse Address Resolution Protocol (RARP) 5) Proxy ARP

Internet Protocol
This protocol works at internet layer. It is responsible for logical addressing, defining type of service and fragmentation.





   

Source Port and Destination Port fields together identify the two local end points of the particular connection. A port plus its hosts IP address forms a unique end point. Ports are used to communicate with the upper layer and distinguish different application sessions on the host. The Sequence Number and Acknowledgment Number fields specify bytes in the byte stream. The sequence number is used for segment differentiation and is useful for reordering or retransmitting lost segments. The Acknowledgment number is set to the next segment expected. Data offset or TCP header length indicates how many 4-byte words are contained in the TCP header. Window indicates how many bytes can be transmitted before an acknowledgment is received. Checksum is used to provide extra reliability and security to the TCP segment. User data represents the actual data which are always included at end of the header.

IP Subnet
In TCP/IP by default three sizes of networks are available: (1) Class A -224 PC -> 16777216 (2) Class B - 216 PC-> 65536

(3) Class C – 28 PC -> 256 In subneting, we will divide class A,B & C network into small size sub networks. This procedure is called subneting. Subneting is performed with the help of subnet mask. There are two types of subneting that we performed: (1) FLSM Fixed Length Subnet Mask (2) VLSM Variable Length Subnet Mask

Why to Sub?

(i) Default Class Network provide us large no. of PCs in comparison to the requirement of PCs in the network. (ii) It is practical never possible to create a class A or class B sized network. To reduce the broadcast of network, we have to perform LAN segmentation of routers. In each sub network, we need different network addresses.

How to Subnet?

In this formula, we will first modify our requirement according to the no. of subnet possible then we calculate new subnet mask and create IP range. Example 1 Class = C No. of subnet =5 Step1 No. of subnet possible is 2,4,8,16,32…… Class= C No. of subnets= 8 Step 2 Calculate key value 2? = No. of subnets 2? = 8 23= 8 Step 3 Calculate new subnet mask In class C Net id 24+key 24+3 27 11111111.11111111.11111111.11100000 255. 255. 255. 224 We add this address to make subnet mask Step 4 Range No. of Pc/Subnet= Total Pc/ No. of Subnet = 256/8 =32 In Class C x.x.x.0 – x.x.x.31

8-key

Host id 8-3 5

(1)(30) x.x.x.32- x.x.x.63 6495 96127 128159 160191 192223 x.x.x.224-x.x.x.255 The first IP of each subnet will be subnet id and last IP will be sub network broadcast address. Example 2 Class= C No. of subnet= 10 Step 1 No. of subnet= 16 Step 2 24= 16 Step 3 Net id Host id 24+4 8-4 11111111.11111111.11111111.11110000

Subneting method 2
Class= No. of Pc/Sub= 8 Mask= ? Range= ?

In this case we have to calculate the key according to the no. of per subnet according to the key value the bits of subnet mask from right hand side are set to zero then range is calculated. Example Class= C No. of Pc/Sub=5 Step 1 No. of Pc/Subnet possible 4,8,16,32,64…. New requirement Class= C No. of Pc/Sub= 8 Step 2 2?= No. of Pc/Sub 2?= 8 23= 8 key 3 11111111.11111111.11111111.11111000 255. 255. 255. 248

No. of Subnet= Total Pc/(Pc/Sub) = 256/8 Class C 255.255.255.248 .8 .16 .24 . . Example 2 Class C No. of Pc/Sub=50 Step 1 Class= C No. of Pc/Sub= 64 Step 2 26= 64 11111111.11111111.11111111.11000000 255. 255. 255. 192 No. of subnet= 256/64= 4 Class C Sub 255.255.255.192 Pc/Sub 4 64 Sub 32 200.100.100.0 200.100.100.7 .15 .23 .31 Pc/Sub 8

Method 3
No. of Pc/Sub= 50 New req. No. of Pc/Sub= 64 No. of Subnet= 256/64= 4 Class= C No. of Sub= 4 22= 4 24+2 8-2 11111111.11111111.11111111.11000000 255. 255. 255. 192

Zero Subnet

According to the rules of IP Addressing the first subnet and last subnet is not useable due to routing problem. In new Cisco router a command is present in default configuration. With this command, we are able to use first and last Subnet after Subneting. Command is Router#config ter Router(config)#ip subnet-zero

Router(config)#exit Example: - Check whether an address is valid IP, N/w address or Broadcast address. If IP is valid then calculate its N/w & Broadcast address. 200.100.100.197 255.255.255.240 28 200.100.100.197 200.100.100.1100 200.100.100.192 200.100.100.1100 200.100.100.207 200.100.100.1100

4 0101 0000 1111 Valid IP Network address Broadcast address

Example: Class= B No. of subnet= 64 26= 64 11111111.11111111.11111111.11000000 255. 255. 255. 192 No. of Pc/Sub= 65536/64= 1024 150.20.0.0 – 150.20.3.255 150.20.4.0 – 150.20.7.255 150.20.8.0 – 150.20.11.255

Prefix Notation of representing IP Address
200.100.100.18 255.255.255.248 200.100.100.18/29 170.20.6.6 255.255.255.224.0 170.20.6.6/19

IP address can be written as IP & Mask as well as IP/Prefix.

This method is representing IP address also called CIDR (Classless Inter Domain Routing) notation.

No Subneting
200.100.1.X 200.100.8.X 200.100.7.X 200.100.4.X 200.100.5.X 200.100.2.X 200.100.6.X 200.100.3.X 200.100.9.X

FLSM
200.100.1.112-127/28 200.100.1.128-143/28 200.100.1.95-111/28 200.100.1.48-63/28 200.100.1.80-95/28 200.100.1.64-79/28 200.100.0-15/28 200.100.1.16-31/28 200.100.1.32-47/28

Remaining Subnet 144 – 159 160 – 175 176 – 191 192 – 207 208 – 223 224 – 239 240 – 255 Problem with FLSM In FLSM, we have to create subnet of equal size. All N/w will be allotted constant size subnet instead of their IP addresses requirement. Due to this a N/w may be allotted more than required IP address and less than required IP addresses.

VLSM
/25 /26 255.255.255.128 255.255.255.248 Sub 4 Pc/Sub 64 /27 /28 /29 255.255.255.192 255.255.255.224 255.255.255.240 Sub 8 Pc/Sub Sub 32 16 Pc/Sub Sub Pc/Sub 16 32 8 0–7 8 – 15 16 – 23 24 - 31

Sub 2

Pc/Sub 128

0 – 127 128 – 255

0 – 63 64 – 127 128 – 191 192 – 255

0 – 31 32 – 63 64 – 95 96 – 127

0 – 15 16 – 31 32 – 47 48 – 63 64 –79 80 – 95 96 – 111

/30 255.255.255.252 Sub 64 Pc/Sub 4

0–3 4–7 8 – 11 12 – 15

20 32-63/30

64 64-95/27

2 4-7/30 2 8-11/30

2 IP 0-3/30 2 12-15/30

5 16-23/29 10 96-111/28 50 128-191/26

Remaining 24 – 31 112 – 127 If we are using VLSM and Dynamic Routing then routing be compatible to VLSM. This will happen only if Subnet masks are also sends in the routing updates.

Super Netting

Combining small N/w to create a large size N/w is called Super Network. Super netting is mostly used to define route summarizations in routing tables. It is not used for the implementation of large network. 170.10.0.0 170.11.0.0 170.00001010.00000000.00000000

170.00001011.00000000.00000000

IP Routing
When we want to connect two or more networks using different n/w addresses then we have to use IP Routing technique. The router will be used to perform routing between the networks. A router will perform following functions for routing. (1) Path determination (2) Packet forwarding (1) Path determination The process of obtaining path in routing table is called path determination. There are three different methods to which router can learn path. i) Automatic detection of directly connected n/w. ii) Static & Default routing iii) Dynamic routing (2) Packet forwarding It is a process that is by default enable in router. The router will perform packet forwarding only if route is available in the routing table.

Routing Process

(i) The pc has a packet in which destination address is not same as the local n/w address. (ii) The pc will send an ARP request for default gateway. The router will reply to the ARP address and inform its Mac address to pc. (iii) The pc will encapsulate data, in which source IP is pc itself, destination IP is server, source Mac is pc‟s LAN interface and destination Mac is router‟s LAN interface. R1 10.0.0.1

PC1 10.0.0.6 S. MAC PC1 D. IP 172.16.0.5 S. IP 10.0.0.6 D. MAC R1

172.16.0.5

The router will receive the frame, store it into the buffer. When obtain packet from the frame then forward data according to the destination IP of packet. The router will obtain a route from routing table according to which next hop IP and interface is selected (iv) According to the next hop, the packet will encapsulated with new frame and data is send to the output queue of the interface.

Static Routing

In this routing, we have to use IP route commands through which we can specify routes for different networks. The administrator will analyze whole internetwork topology and then specify the route for each n/w that is not directly connected to the router.

Steps to perform static routing (1) Create a list of all n/w present in internetwork. (2) Remove the n/w address from list, which is directly connected to n/w. (3) Specify each route for each routing n/w by using IP route command. Router(config)#ip route <destination n/w> <mask> <next hop ip> Next hop IP it is the IP address of neighbor router that is directly connected our router. Static Routing Example: Router#conf ter Router(config)#ip route 10.0.0.0 255.0.0.0 192.168.10.2

Advantages of static routing
(1) Fast and efficient. (2) More control over selected path. (3) Less overhead for router. (4) Bandwidth of interfaces is not consumed in routing updates.

Disadvantages of static routing
(1) More overheads on administrator. (2) Load balancing is not easily possible. (3) In case of topology change routing table has to be change manually.

Alternate command to specify static route
Static route can also specify in following syntax: Old Router(config)#ip route 172.16.0.0 255.255.0.0 172.25.0.2 Or Router(config)#ip route 172.16.0.0 255.255.0.0 serial 0

Backup route or loading static route
If more than one path are available from our router to destination then we can specify one route as primary and other route as backup route. Administrator Distance is used to specify one route as primary and other route as backup. Router will select lower AD route to forward the traffic. By default static route has AD value of 1. With backup path, we will specify higher AD so that this route will be used if primary route is unavailable. Protocols Directly Connected Static BGP EIGRP IGRP OSPF RIP AD 0 1 20 90 100 110 120

Syntax: - To set backup path Router(config)#ip route <dest. n/w> <mask> <next hop> <AD> Or <exit interface>

Example: Router#conf ter Router(config)#ip route 150.10.0.0 255.255.0.0 150.20.0.5 Router(config)#ip route 150.10.0.0 25.255.0.0 160.20.1.1 8 (below 20) Router(config)#exit

Default Routing

Default routing means a route for any n/w. these routes are specify with the help of following syntax: Router(config)#ip route 0.0.0.0 0.0.0.0 <next hop> Or <exit interface> This type of routing is used in following scenario. Scenario 1: Stub network A n/w which has only one exit interface is called stub network.

R

If there is one next hop then we can use default routing. Scenario 2 Internet connectivity On Internet, million of n/ws are present. So we have to specify default routing on our router. Default route is also called gateway of last resort. This route will be used when no other routing protocol is available. 200.100.100.11 ISP

172.16.0.5 R1 R2 10.0.0.0

Router(config)#ip route 10.0.0.0 255.0.0.0 172.16.0.5 Router(config)#ip route 0.0.0.0 0.0.0.0 200.100.100.11 To display routing table Router#sh ip route To display static routes only Router#sh ip route static To display connected n/ws only Router#sh ip route connected S 192.168.10.0/28 [1/0] via 172.16.0.5 To check all the interface of a router Router#sh interface brief

Dynamic Routing

In dynamic routing, we will enable a routing protocol on router. This protocol will send its routing information to the neighbor router. This protocol will send its routing information to the neighbor router. The neighbors will analyze the information and write new routes to the routing table. The routers will pass routing information receive from one router to other router also. If there are more than one path available then routes are compared and best path is selected. Some examples of dynamic protocol are: RIP, IGRP, EIGRP, OSPF

Types of Dynamic Routing Protocols
According to the working there are two types of Dynamic Routing Protocols. (1) Distance Vector (2) Link State According to the type of area in which protocol is used there are again two types of protocol: (1) Interior Routing Protocol (2) Exterior Routing Protocol

Autonomous system
Autonomous system is the group of contiguous routers and n/w, which will share their routing information directly with each other. If all routers are in single domain and they share their information directly with each other then the size of routing updates will depend on the no. of n/w present in the Internetwork. Update for each n/w may take 150 – 200 bytes information. For example: - if there are 1000 n/ws then size of update will be 200*1000 = 200000 bytes The routing information is send periodically so it may consume a large amount of bandwidth in our n/w. Border Routing Exterior Routing

Interior Routing AS 200 Domain AS 400 AS 500

Protocols
Interior Routing RIP IGRP EIGRP OSPF Exterior Routing BGP EXEIGRP

Distance Vector Routing
The Routing, which is based on two parameters, that is distance and direction is called Distance Vector Routing. The example of Distance Vector Routing is RIP & IGRP. Operation: (1) Each Router will send its directly connected information to the neighbor router. This information is send periodically to the neighbors. (2) The neighbor will receive routing updates and process the route according to following conditions: (i) If update of a new n/w is received then this information is stored in routing table. (ii) If update of a route is received which is already present in routing table then route will be refresh that is route times is reset to zero. (iii) If update is received for a route with lower metric then the route, which is already present in our routing table. The router will discard old route and write the new route in the routing table. (iv) If update is received with higher metric then the route that is already present in routing table, in this case the new update will be discard. (3) A timer is associated with each route. The router will forward routing information on all interfaces and entire routing table is send to the neighbor. There are three types of timers associated with a route. (i) Route update timer It is the time after which the router will send periodic update to the neighbor. (ii) Route invalid timer It is the time after which the route is declared invalid, if there are no updates for the route. Invalid route are not forwarded to neighbor routers but it is still used to forward the traffic. (iii) Route flush timer It is the time after which route is removed from the routing table, if there are no updates about the router.

Metric of Dynamic Routing
Metric are the measuring unit to calculate the distance of destination n/w. A protocol may use a one or more than one at a time to calculate the distance. Different types of metric are: (1) Hop Count (2) Band Width (3) Load (4) Reliability (5) Delay (6) MTU Hop Count:It is the no. of Hops (Routers) a packet has to travel for a destination n/w. Bandwidth : Bandwidth is the speed of link & path with higher bandwidth is preferred to send data. Load : Load is the amount of traffic present in the interface. Paths with lower load and high throughput is used to send data. Reliability : Reliability is up time of interface over a period of time. Delay : Delay is the time period b/w a packet is sent and received by the destination. MTU : Maximum Transmission Unit It is the maximum size of packet that can be sent in a frame mostly MTU is set to 1500.

Problems of Distance Vector

There are two main problems of distance vector routing (1) Bandwidth Consumption (2) Routing Loops Bandwidth Consumption The problem of accessive bandwidth consumption is solved out with the help of autonomous system. It exchanges b/w different routers. We can also perform route summarization to reduce the traffic.

Routing Loops It may occur between adjacent routers due to wrong routing information. Distance Vector routing is also called routing by Rumor. Due to this the packet may enter in the loop condition until their TTL is expired.

Method to solve routing loops
There are five different methods to solve or reduce the problem of routing loop. (1) Maximum Hop Count (2) Flash Updates/Triggered Updates (3) Split Horizon (4) Poison Reverse (5) Hold Down Maximum Hop Count This method limits the maximum no. of hops a packet can travel. This method does not solve loop problem. But it reduce the loop size in the n/w. Due to this method the end to end size of a n/w is also limited. Flash Updates/Triggered Updates In this method a partial update is send to the all neighbors as soon as there is topology change. The router, which receives flash updates, will also send the flash updates to the neighbor routers. Split Horizon Split Horizon states a route that update receive from an interface can not be send back to same interface. Poison Reverse This method is the combination of split Horizon and Flash updates. It implements the rule that information received from the interface can not be sent back to the interface and in case of topology change flash updates will be send to the neighbor. Hold Down If a route changes frequently then the route is declared in Hold Down state and no updates are received until the Hold Down timer expires.

Routing Information Protocol
Features of RIP:  Distance Vector  Open standard  Broadcast Updates (255.255.255.255)  Metric Hop Count Timers Update 30 sec Invalid 180 sec Hold 180 sec Flush 240 sec * Loop Control Split Horizon Triggered Updates Maximum Hop Count Hold Down * Maximum Hop Count 15 * Administrative Distance 120 * Equal Path Cost Load Balancing * Maximum Load path 6

Default 4 * Does not support VLSM * Does not support Autonomous system

Configuring RIP Router#conf ter Router(config)#router rip Router(config-router)#network <own net address> Router(config-router)#network <own net address> --------------------------Router(config-router)#exit 172.16.0.6 10.0.0.1 R1 200.100.100.12 172.16.0.5 175.2.1.1

Router(config-router)#network 10.0.0.0 Router(config-router)#network 172.16.0.0 Router(config-router)#network 200.100.100.0 175.2.0.0 via 172.16.0.6 Display RIP Routers Router#sh ip route rip R 192.168.75.0/24 [120/5] via 172.30.0.2 00:00:25 serial 1/0 RIP Dest. n/w mask AD Metric Next Hop Timer own Interface RIP advanced configuration Passive Interfaces An interface, which is not able to send routing updates but able to receive routing update only is called Passive Interface. We can declare an interface as passive with following commands: Router#conf ter Router(config)#router rip Router(config-router)#Passive-interface <type> <no> Router(config-router)#exit

Neighbor RIP In RIP, by default routing updates are send to the address 255.255.255.255. In some scenarios, it may be required to send routing updates as a unicast from router to another. In this case, we have to configure neighbor RIP. For example: - in a Frame Relay n/w the broadcast update is discarded by the switches, so if we want to send RIP updates across the switches then we have to unicast updates using Neighbor RIP. Unicast 10.0.0.2 255.255.255.255 10.0.0.1 R1 10.0.0.2 R2 Frame Relay Cloud

R1 Router(config)#router rip Router(config-router)#neighbor 10.0.0.2

R2 Router(config)#router rip Router(config-router)#neighbor 10.0.0.1

Configuring Timers Router(config)#router rip Router(config-router)#timers basic <update> <invalid> <hold down> <flush> Router(config-router)#exit Example: Router(conf)#timer basic 50 200 210 300 Update 50 sec Invalid 200 sec Hold 210 sec Flush 300 sec To change Administrative Distance Router(config)#router rip Router(config-router)#distance <value> Router(config-router)#exit 95 or 100 To configure Load Balance RIP is able to perform equal path cost Load Balancing. If multiple paths are available with equal Hop Count for the destination then RIP will balance load equally on all paths. Load Balancing is enabled by default 4 paths. We can change the no. of paths. It can use simultaneously by following command: Router(config)#router rip Router(config-router)#maximum-path <1-6> To display RIP parameters Router#sh ip protocol Or Router#sh ip protocol RIP This command display following parameters: (i) RIP Timers (ii) RIP Version

(iii) Route filtering (iv) Route redistribution (v) Interfaces on which update send (vi) And receive (vii) Advertise n/w (viii) Passive interface (ix) Neighbor RIP (x) Routing information sources (xi) Administrative Distance

RIP version 2

RIP version 2 supports following new features: (1) Support VLSM (send mask in updates) (2) Multicast updates using address 224.0.0.9 (3) Support authentication Commands to enable RIP version 2 We have to change RIP version 1 to RIP version 2. Rest all communication will remain same in RIP version 2. Router(config)#Router RIP Router(config-router)#version 2 Router(config-router)#exit To debug RIP routing Router#debug ip rip To disable debug routing Router#no debug ip rip Or Router#no debug all Or Router#undebug all

Interior Gateway Routing Protocol

Features: * Cisco proprietary * Distance vector * Timers Update 90 sec Invalid 270 sec Hold time 280 sec Flush 630 sec * Loop control All methods * Max hop count 100 upto 255 * Metric (24 bit composite) Bandwidth (default) Delay (default) Load Reliability MTU * Broadcast updates to address 255.255.255.255 * Unequal path cost load balancing * Automatic route summarization

* Support AS * Does not support VLSM

Configuring IGRP
Router(config)#router igrp <as no>(1 – 65535) Router(config-router)#network <net address> Router(config-router)#network <net address> Router(config-router)#exit Configuring Bandwidth on Interface for IGRP By default the router will detect maximum speed of interface and use this value as the bandwidth metric for IGRP. But it may be possible that the interfaces and working at its maximum speed then we have to configure bandwidth on interface, so that IGRP is able to calculate correct method. Router(config)#interface <type> <no> Router(config-if)#bandwidth <value in kbps> Router(config-if)#exit Router(config)#interface serial 0 Router(config-if)#bandwidth 256 Router(config-if)#exit Serial E1 modem Serial E1

2048 k 256 k sync

2048 k

Configuring Unequal path cost load balancing To configure load balancing, we have to set two parameters (1) Maximum path (by default 4) (2) Variance (default 1) Maximum Path: - it is maximum no. of paths that can be used for load balancing simultaneously. Variance: - it is the multiplier value to the least metric for a destination n/w up to which the load can be balanced. Router(config)#Router igrp <as no> Router(config-router)#variance <value> Router(config-router)#exit Configuring following options in IGRP as same as in case of RIP: (1) Neighbor (2) Passive interface (3) Timer (4) Distance (AD) (5) Maximum path

Neighbor Topology 11.0.0.1 R1 11.0.0.0 dc 13.0.0.2 12.0.0.0 dc 13.0.0.0 dc R2 11.0.0.0 10.0.0.0 R3 13.0.0.0 14.0.0.0 15.0.0.0 16.0.0.0 R4 16.0.0.0 17.0.0.0 R5 18.0.0.0 19.0.0.0 20.0.0.0 14.0.0.0 R6 20.0.0.0 21.0.0.0

Routing

19.0.0.0 18.0.0.0 14.0.0.0

R6 21.0.0.0

20.0.0.0

R5

15.0.0.0 16.0.0.0 17.0.0.0

R3 13.0.0.0

R1

11.0.0.0

R2

10.0.0.0

12.0.0.0

R4

Link State Routing

This type of routing is based on link state. Its working is explain as under (1) Each router will send Hello packets to all neighbors using all interfaces. (2) The router from which Hello reply receive are stored in the neighborship table. Hello packets are send periodically to maintain the neighbor table. (3) The router will send link state information to the all neighbors. Link state information from one neighbor is also forwarded to other neighbor. (4) Each router will maintain its link state database created from link state advertisement received from different routers. (5) The router will use best path algorithm to store the path in routing table. Problems of Link State Routing The main problems of link state routing are: (1) High bandwidth consumption. (2) More hardware resources required that is processor and memory (RAM) The routing protocols, which use link state routing are: (1) OSPF (2) EIGRP

Enhanced Interior Gateway Routing Protocol
Features: * Cisco proprietary * Hybrid protocol Link State Distance Vector * Multicast Updates using Address 224.0.0.10 * Support AS * Support VLSM * Automatic Route Summarization * Unequal path cost load balancing * Metric (32 bit composite) Bandwidth Delay Load Reliability MTU * Neighbor Recovery * Partial updates * Triggered updates * Backup Route * Multi Protocol Routing

EIGRP Protocols & Modules (1) Protocol depended module This module is used to perform multi protocol routing that is the router will maintain 3 routing table for TCP/IP, IPX/SPX and Appletalk. It will analyze the update packet and send to the corresponding routing table. Reliable Transport Protocol RTP is used to exchange routing updates with neighbor routers. It will also maintain neighbor relationship with the help of Hello packet. RTP has following features: (1) Multicast updates (224.0.0.10) (2) Neighbor recovery: If neighbor stops responding to the Hello packets then RTP will send 16 unicast Hello packet for that neighbor. (3) Partial updates (4) No updates are send if there is no topology change. Due to this feature it is also called quiet protocol. Diffusing Update Algorithm (DUAL) DUAL is responsible for calculating best path from the topology table. Dual has following features: * Backup Path * VLSM * Route queries to neighbor for unknown n/w.

Configuring EIGRP Router(config)#router eigrp <as no> Router(config-router)#network <net addr.> Router(config-router)#network <net addr.> Router(config-router)#exit Advanced Configuration EIGRP Configuring following options are same as configuring IGRP (1) Bandwidth on Interfaces (2) Neighbor (3) Load balancing Max path Variance Display Commands Router#clear ip route * Flush routing table. Router#sh ip eigrp topology It shows topology database. P-> passive-> stable A->active->under updation Router#sh ip eigrp neighbor It shows neighbor table Debug IGRP Router#debug ip igrp events Its display info. On special event Router#debug ip igrp transactions It shows every update Debug EIGRP Router#debug ip eigrp Router#debug ip eigrp summary

Open Shortest Path First
Features: * Link State * Open standard * Multicast updates 224.0.0.5 224.0.0.6 * Support VLSM * Support Area similar to AS * Manual Route Summarization * Hierarchical model * Metric Bandwidth * Equal path cost load balancing * Support authentication * Unlimited hop count

OSPF Terminology Already known topics in this: (1) Hello packets (2) LSA (Link State Advertisement) (3) Neighbor (4) Neighbor table (5) Topology table (LSA database) Router ID Router ID is the highest IP address of router interfaces. This id is used as the identity of the router. It maintaining stale databases. The first preference for selecting router ID is given to the Logical interfaces. If logical interface is not present then highest IP of physical interface is selected as router id.

Area Area is the group of routers & n/ws, which can share their routing information directly with each other. Adjacency A router is called adjacency when neighbor relationship is established. We can also say adjacency relationship is formed between the routers.

OSPF Hierarchical Model

Area 0

br

br

br

abr

abr

abr

ar

ar

ar

ar

ar

ar

ar

Area 20

Area 70

Area 90

Area Router A router, which has all interfaces member of single area, is called area router. Backbone Area Area 0 is called backbone area. All other areas must connect to the backbone area for communication. Backbone Router A router, which has all interfaces members of area 0, is called backbone router. Area Border Router A router, which connects an area with area 0, is called area border router.

LSA Flooding in OSPF
If there are multiple OSPF routers on multi access n/w then there will be excessive no. of LSA generated by the router and they can choke bandwidth of the network. Designated Router A router with highest RID (router id) will be designated router for a particular interface. This router is responsible for receiving LSA from non-DR router and forward LSA to the all DR router. Backup Designated Router This router will work as backup for the designated router. In BDR mode, it will receive all information but do not forward this information to other non-DR router.

L

K

M

N

A

B

C

D

Switch A B C D L B A C D K C A B D M D A B C N

Neighbor

This problem is solved with the help of electing a router as designated router and backup designated router.

Commands to configure OSPF Router#conf ter Router(config)#router ospf <process no> Router(config-router)#network <net address> <wild mask> area <area id> Router(config-router)#network <net address> <wild mask> area <area id> Router(config-router)#exit Wild Mask – Complement of subnet mask Example 255.255.0.0 255.255.255.255 - Subnet mask Wild mask 0.0.255.255 255.255.255.255 - 0.255.255.192 0 . 0 . 0 . 63

Configuring bandwidth on interface If the actual bandwidth of interface is not equal to the maximum speed of interface then we have to use bandwidth command to specify the actual bandwidth. Router(config)#interface <type> <no> Router(config-if)#bandwidth <speed> Configuring logical interface for OSPF By default the highest IP address of interface will be elected as Router id. If there is a change in status of interface then router will reelect some IP as Router id. So if we create logical interface, it will never go down and first preference give to the logical interface for RID. Command: Router(config)#interface loopback <no> Router(config-if)#ip address 200.100.100.1 255.255.255.255 Router(config-if)#no sh Router(config-if)#exit The subnet mask 255.255.255.255 is called host mask. It is recommended to use this mask due to which minimum IP address will be wasted. Command to display OSPF parameter Router#show ip protocol Router#show ip ospf Display Neighbor Table Router#show ip ospf neighbor Display Database Router#show ip ospf database To display DR/BDR Elections Router#show ip ospf interfaces

Area 20 200.100.100.2/24

215.1.13/24

Router(config)#router ospf 32 Router(config-router)#network 200.100.100.0 0.0.0.255 area 20 Router(config-router)#network 215.1.1.0 0.0.0.255 area 20 Router(config-router)#exit

Area 0 R1 200.100.100.33/30 200.100.100.34/30

R2

200.100.100.66/27

200.100.100.160/26

R1 Router(config)#router ospf 33 Router(config-router)#network 200.100.100.32 0.0.0.3 area 0 Router(config-router)#network 200.100.100.64 0.0.0.31 area 0 Router(config-router)#exit R2 Router(config)#router ospf 2 Router(config-router)#network 200.100.100.32 0.0.0.3 area 0 Router(config-router)#network 200.100.100.128 0.0.0.63 area 0 Router(config-router)#exit 200.100.100.5/30 R1 200.100.100.6/30 R2 200.100.100.18/30 200.100.100.230/27 200.100.100.38/28 200.100.100.161/28 200.100.100.17/30 R3

R1 Router(config-router)#network 200.100.100.4 0.0.0.3 Router(config-router)#network 200.100.100.32 0.0.0.15 R2 Router(config-router)#network 200.100.100.4 0.0.0.3 Router(config-router)#network 200.100.100.160 0.0.0.15 Router(config-router)#network 200.100.100.16 0.0.0.3 R3 Router(config-router)#network 200.100.100.16 0.0.0.3 Router(config-router)#network 200.100.100.224 0.0.0.31

LAN Switching Ethernet switches are used in LAN to create Ethernet networks. Switches forward the traffic on the basis of MAC address. Switches maintain a switching table in which MAC addresses and Port No are used to perform switching decision. Working of bridge and switch is similar to each other.

Classification of switches
Switches are classified according to the following criteria: Types of switches based on working (1) Store & Forward This switch receives entire frame then perform error checking and start forwarding data to the destination. (2) Cut through This switch starts forwarding frame as soon as first six bytes of the frame are received. (3) Fragment-free This switch receives 64 bytes of the frame, perform error checking and then start forwarding data. (4) Adaptive cut-through It changes its mode according the condition. If there are errors in frames then it changes its mode to Store & Forward. Types of switches based on management (1) Manageable switches (2) Non-Manageable switches (3) Semi-Manageable switches Types of switches based on command mode (only in Cisco) (1) IOS based (2) CLI based Features of switch - No. of ports - Type of media Types of switches based on OSI layer (1) Layer 2 switches (only switching) (2) Layer 3 switches (switching & routing)

Switches based on hierarchical model (1) Core layer switches (2) Distribution layer switches (3) Access layer switches

- Speed of ports - Switching or Wire speed or Throughput

Basic Switch Administration
IOS based switches are similar to the routers. We can perform following function on switches in a similar manner as performed on router. Access switch using console Commands to enter & exit from different mode Commands to configure passwords Manage configuration Backup IOS and configuration Configuring and resolving hostnames Managing telnet Configuring CDP Configuring time clock Configuring Banners Command line shortcuts and editing shortcuts Managing history Configure logging Boot system commands

Following function and options are not similar in router and switch. Default hostname is „Switch‟ Auxiliary port is not present VTY ports are mostly 0 to 15 By default interfaces are enabled IP address cannot be assign to interfaces Routing configuration mode is not present Interface no. starts from 1 Web access is by default enabled Configuration register is not same Flash memory may contain multiple files Startup-configuration is also saved in flash

Configuring IP and Gateway on switch
We can configure IP address on switch for web access or telnet IP address is required for the administration of the switch. If we have to access switch from remote n/w then we will configure default gateway in addition to IP address. Assigning IP to logical interface:Switch(config)#interface vlan 1 Switch(config)#IP address <ip> <mask> Switch(config)#no sh Switch(config)#exit Configuring Gateway Switch(config)#ip default-gateway <ip> Switch(config)#exit

Breaking Switch Password (1) Power off switch press mode button present in front of switch then power on the switch. (2) Keep mode button press until „Switch:‟ prompt appears on console. (3) In switch monitor mode, type following commands: flash_init load_helper rename flash:config.text flash:<anyname> dir flash: boot (4) After booting switch will prompt to enter in initial configuration dialog. Enter „no‟ here and type. Switch>enable Rename flash:<anyname> Flash:config.text Configure memory Change password and save config. Then copy run strat_config.

Cisco Hierarchal Model
When we want to create a large sized LAN network then we may face following problems if we are going design the network in flat model.  High latency  Conjunction between switches between switches  Large broadcast domain Cisco hierarchal model recommends three layer design of the network o Core layer o Distribution layer o Access layer On each layer there are some rules which we have to follow  Highest performance devices are connected on Core layer.  Resources should be placed on Core layer.  Polices should not be applied on core layer.

  

On distribution layer, we can implement policies. Distribution and Core devices should be connected with high-speed links. Access layer devices are basic devices and may be non manageable.

Hierarchal model

After using hierarchal model the most of LAN problem will be solved but one problem still remain same that is all pc s will be in single broadcast domain. We have to implement following solution for this problem. (1) Physical Segmentation (2) Logical Segmentation Logical Segmentation of Network To perform logical segmentation, we have to create VLAN in the network. With the help of VLAN, we can logically divide the broadcast domain of the network.

VLAN (Virtual LAN)
VLAN provides Virtual Segmentation of Broadcast Domain in the network. The devices, which are member of same Vlan, are able to communicate with each other. The devices of different Vlan may communicate with each other with routing. So that different Vlan devices will use different n/w addresses. Vlan provides following advantages: (1) Logical Segmentation of network (2) Enhance network security

Creating port based Vlan In port based Vlan, first we have to create a VLAN on switch then we have to add ports to the Vlan. Commands to create Vlan Switch#config ter Switch(config)#vlan <no> Switch(config)#name <word> Switch(config)#exit Commands to configure ports for a Vlan Switch#conf ter Switch(config)#interface <type> <no> Switch(config-if)#switchport access vlan <no> Switch(config-if)#exit

By default, all ports are member of single vlan that is Vlan1. we can change vlan membership according to our requirement. Commands to configure multiple ports in a vlan Switch#conf ter Switch(config)#interface range <type> <slot/port no (space)–(space) port no> Switch(config-if)#switchport access vlan <no> Switch(config-if)#exit Example: - Suppose we want to add interface fast Ethernet 0/10 to 0/18 in vlan5 Switch#config ter Switch(config)#interface range fastethernet 0/10 – 18 Switch(config-if)#switchport access vlan 5 Switchconfig-if#exit

To display mac address table
Switch#sh mac-address-table

To Display Vlan and port membership Switch#sh vlan

Trunking
When there are multiple switches then we have to use trunk links to connect one switch with other. If we are not using trunk links then we have to connect one cable from each VLAN to the corresponding VLAN of the other switch. Normal: Vlan 1 7 3 1 3 7

In Trunking: 1 7 3

Vlan 1, 3, 7 1 3 7

Trunk Trunk Switches will perform trunking with the help of frame tagging. The trunk port will send data frames by adding a Vlan id information to the frame, at the receiving end vlan id information is removing from the end and according to the tag data is delivered to the corresponding vlan. There are two protocols to perform frame tagging. (1) Inter switch link (cisco propietry) (2) IEEE 802.1 q

Configuring Trunking In cisco switches all switch ports may be configured in three modes (1) Trunk desirable (default) (2) Trunk on (3) Trunk off Switch#conf ter Switch(config)#interface <type> <no> Switch(config-if)#switchport mode <trunk|access|auto> Switch(config-if)#exit on off desirable To configure Vlans allowed on Trunk By default all Vlans are allowed on Trunk port. We can add/remove a partucular Vlan from trunk port with following command Switch#config ter Switch(config)#interface <type> <no> Switch(config-if)#switchport trunk allowed vlan all Remove <vlan> Add <vlan>

Except <vlan> To display trunk interfaces Switch#sh interface trunk Switch#sh interface <type> <no> trunk

Vlan Trunking Protocol (VTP)
With the help of VTP, we can simplify the process of creating Vlan. In multiple switches, we can configure one switch as VTP server and all other switches will be configured as VTP client. We will create Vlans on VTP server switch. The server will send periodic updates to VTP client switches. The clients will create Vlans from the update received from the VTP server. VTP server VTP server is a switch in which we can create, delete or modify Vlans. The server will send periodic updates for VTP clients.

VTP client On VTP client, we are not able to create, modify or delete Vlans. The client will receive and forward vtp updates. The client will create same Vlans as defined in vtp update. VTP Transparent Transparent is a switch, which will receive and forward VTP update. It is able to create, delete and modify Vlans locally. A transparent will not send its own VTP updates and will not learn any information from received vtp update.

VTP Server Vlan 1,3,5,10,20 Client Client

Vlan 1,3,5,10,20 Clinet Vlan 1,3,10,20,40,90

Client

Client

Client

Client

VTP Transparent Commands Switch#conf ter Switch(config)#vtp domain <name> Switch(config)#vtp password <word> Switch(config)#vtp mode <server|client|transparent> Switch(config)#exit By default in cisco switches the VTP mode is set as VTP server with no domain and no password. To display VTP status Switch#sh vtp status

VTP Pruning
Pruning is the VTP feature through which a trunk link can be automatically disable, for a particular Vlan if neighbor switch does not contain ports in that Vlan. Vlan1 is not prun eligible. Command to configure VTP Pruning We have to use only one command on VTP server for VTP Pruning. Switch#conf ter Switch(config)#vtp pruning Switch(config)#exit

Server

Vlan 1,3,5,7

Client Vlan 1 3 5 7

Client 1 3 5 7 1

Client 3 5 7

Inter Vlan Communication
After creating Vlans, each Vlan has own broadcast domain. If we want communication from one Vlan to another Vlan then we need to perform routing. There are three methods for inter vlan communication. (1) Inter Vlan using router on a stick method (2) Inter Vlan using layer 3 switch (1) Inter Vlan using router on a stick method In this method a special router is used for Inter Vlan. In this router, we can create one interface for each Vlan. The physical interface of router will be connected on trunk port switch. This router will route traffic on the same interface by swapping vlan id information with the help of frame tagging protocol.

Router

Fa 0/0.1 – 10.0.0.1 -> Vlan1 Fa 0/0.2 – 11.0.0.1 -> Vlan3 Fa 0/0.3 – 12.0.0.1 -> Vlan5

Fa 0/0

T

Trunk T

Vlan 1, 3, 5 T

T 1 N/w 10.x.x.x Gateway 10.0.0.1 3 5 1

T 3 11.x.x.x 11.0.0.1 5 1

T 3 5 12.x.x.x 12.0.0.1 Router(config)#interface fastethernet 0/0.2 Router(config-if)#encapsulation dot1q 3 Router(config-if)#ip address 11.0.0.1 255.0.0.0 Router(config-if)#no sh Router(config-if)#exit Router(config)#interface fastethernet 0/0.3 Router(config-if)#encapsulation dot1q 5 Router(config-if)#ip address 12.0.0.1 255.0.0.0 Router(config-if)#no sh Router(config-if)#exit

Configuration on Router Router#config ter Router(config)#interface fastethernet 0/0 Router(config-if)#no ip address Router(config-if)#no sh Router(config-if)#exit Router(config)#interface fastethernet 0/0.1 Router(config-if)#encapsulation dot1q 1 Router(config-if)#ip address 10.0.0.1 255.0.0.0 Router(config-if)#no sh Router(config-if)#exit

Configuration on Core switch (1) Configure switch as VTP server (2) Create Vlans (3) Configure interface connected to router as Trunk (4) Configure interfaces connected to other switches as trunk (if required) Configuration on Distribution layer switches (1) Configure switch as VTP client

(2) Configure required interface as Trunk (optional) (3) Add ports to Vlan Configuration on Pc Configure IP and Gateway

Spanning Tree Protocol
When we connect multiple switches with each other and multiple path exist from one switch to another switch then it may lead to the switching loop in the network. Multiple paths are used to create redundancy in the network. STP is only required when multiple path exist then there is possibility of loop in n/w. Packets Switch Switch Switch

Problems the occur with redundancy path (1) Multiple copies of the frame will be received by destination. (2) Frequent changes in the mac address table of switch. (3) A mac address may appear at multiple ports in a switch. (4) Packets may enter in the endless loop. Spanning Tree Protocol will solve this problem by blocking the redundancy interface. So that only one path will remain active in the switches. If the primary path goes down then disabled link will become enable and data will be transferred through that path. Working of STP The STP will create a topology database in which one switch will be elected as root switch. Path cost is calculated on the basis of bandwidth. The lowest path cost link will be enable mode and another path will be disable.

Root Switch 1 Gb Switch 1 Gb Switch

100 Mb Switch 100 Mb Lowest cost (Disable) STP terminology (1) Bridge id

100 Mb Switch

It is the combination of bridge priority and base mac address. In Cisco switches default priority no. is 32768. (2) Root Bridge The Bridge/Switch with lowest Bridge id will become the Root Bridge. The Root Bridge is used as the center point for calculating path cost in topology. (3) BPDU Bridging Protocol Data Units It is the STP information, which is exchange between the switches to create topology and path selection. (4) STP port mode An STP is enabled a port may be in one of the following mode. (i) Listening: - in this mode a port will send/receive BPD. (ii) Learning: - a port will learn mac address table. (iii) Forwarding: - the port will forward data based on mac address table. (iv) Blocking: - the port is block to send/receive data by Spanning Tree Protocol. (v) Disable: - the port is administratively disabled. Path cost calculation The links in switches will be enable or disabled on the basis of path cost. The path cost for each link is calculated according to following table. Speed 10 Mb 100 Mb 1 Gb 10 Gb Old IEEE Cost 100 10 1 1 New IEEE Cost 100 19 4 2

To configure ports for forwarding mode directly Switch#config ter Switch(config)#interface <type> <no> Switch(config-if)#switchport host Configuring port security In manageable switches, we can restrict the no. of mac addresses that a port can learn. Even we can specify the mac address statically with a command. With port security, we can also specify the action to be perform if port security violation is detected. Switch#conf ter Switch(config)#interface <type> <no> Switch(config-if)#switchport port-security Switch(config-if)#switchport port-security maximum <no. of mac> Switch(config-if)#switchport port-security violation <shutdown|restrict|reject> Switch(config-if)#switchport port-security mac-address sticky Switch(config-if)#switchport port-security mac-address sticky <mac address> Switch(config-if)#exit

Access Control List

ACL are the basic security feature that is required in any network to control the flow of traffic. Most of time our network may have servers and clients for which traffic control is required. We can also use ACL to classify the traffic. ACLs are used in features like QOS (Quality of Service), Prioritize traffic and interesting traffic for ISDN. Classification Access Control List: Types of ACL based on Protocol: (1) IP Access Control List (2) IPX Access Control List (3) Appletalk Access Control List Types of ACL based on Feature: (1) Standard ACL (2) Extended ACL Types of ACL based on Access mode: (1) Numbered ACL (2) Named ACL Types of ACL based on Order of rules: (1) Deny, permit (2) Permit, deny Types of ACL based on direction: (1) Inbound ACL (2) Outbound ACL

Flow chart of Inbound ACL

A Packet is received

Is there any Access-list applied on interface in Inbound direction?

No

The packet is passed to Routing Engine

Yes

Is there any macthing rule in ACL from topdown order?

No

The packet is dropped.

Yes

The packet is passed to RE

Yes

Is it permit?

No

The packet is dropped.

IP Standard ACL (Numbered) In Standard ACL, we are only able to specify source address for the filtering of packets. The syntax to create IP standard ACL are: Router#conf ter Router(config)#access-list <no> <permit|deny> <source>

Router(config)#exit <source> Single pc host 192.168.10.5 192.168.10.5 192.168.10.5 0.0.0.0 200.100.100.0 0.0.0.255 200.100.100.32 0.0.0.15 any

N/w Subnet All

Applying ACL on interface Router#conf ter Router(config)#interface <type> <no> Router(config-if)#ip access-group <ACL no.> <in|out> Router(config-if)#exit Rule for applying ACL

Only one ACL can be applied on each interface, in each direction for each protocol.
Example: - Suppose we want to allow Internet only for 192.168.10.32 – 70. Internet Router(config)#access-list 25 permit 192.168.10.32 0.0..31 Router(config)#access-list 25 permit 192.168.10.64 0.0.0.3 Router(config)#access-list 25 permit 192.168.10.68 Router(config)#access-list 25 permit 192.168.10.69 Router(config)#access-list 25 permit 192.168.10.70 Router(config)#interface serial 0 Router(config-if)#ip access-group 25 out

Router

IP Standard ACL (Named) In Numbered ACL editing feature is not available that is we are not able to delete single rule from the ACL. In Named ACL editing feature is available. Router#config ter Router(config)#ip access-list standard <name> Router(config-std-nacl)#<deny|permit> <source> Router(config-std-nacl)#exit Router#conf ter Router(config)#ip access-list standard abc Router(config-std-nacl)#deny 172.16.0.16 Router(config-std-nacl)#deny 172.16.0.17 Router(config-std-nacl)#deny 172.16.0.18 Router(config-std-nacl)#permit any Router(config-std-nacl)#exit To modify the ACL Router#conf ter Router(config)#ip access-list standard abc Router(config-std-nacl)#no deny 172.16.0.17 Router(config-std-nacl)#exit

To control Telnet access using ACL If we want to control telnet with the help of ACL then we can create a standard ACL and apply this ACL on vty port. The ACL that we will create for vty will be permit – deny order. Example: - suppose we want to allow telnet to our router from 192.168.10.5 & 200.100.100.30 pc. Router#conf ter Router(config)#access-list 50 permit 192.168.10.5 Router(config)#access-list 50 permit 192.168.10.30 Router(config)#access-list 50 deny Router(config)#line vty 0 4 Router(config-line)#access-class 50 in Router(config)#exit

IP Extended ACL (Numbered)
Extended ACL are advanced ACL. ACL, which can control traffic flow on the basis of five different parameters that are: (i) Source address (ii) Destination address (iii) Source port (iv) Destination port (v) Protocol (layer 3/layer 4) The syntax to create Extended ACL Router#conf ter Router(config)#access-list <no> <deny|permit> <protocol> <source> [<s.port>] <destination> [<d.port>] router(config)#exit <no> -> 100 to 199 <protocol> -> layer 3 or layer 4 IP TCP UDP ICMP IGRP <Source port> no (1 to 65535) or <Destination port> telnet/www/ftp etc. <Source> <Destination> Example rules of Extended ACL Router(config)#access-list 140 deny ip 192.168.10.3 0.0.0.0 any (All tcp/ip data is denied from source 192.168.10.3 to any destination) Router(config)#access-list 120 permit ip any any (All tcp/ip data permit from any source to any destination) Router(config)#access-list 145 deny tcp any host 200.100.100.5 (All tcp data is denied from any source to host 200.100.100.5) Router(config)#access-list 130 permit tcp any host 200.100.100.10 eq 80 (All tcp based data from any source is allowed to access destination 200.100.100.10 on port no. 80 that is www(http) ) – web access Router(config)#access-list 130 permit udp any host 200.100.100.10 eq 53 (Any pc is able to access our DNS service running on port no. 53) Router(config)#access-list 150 deny tcp any any eq 23 [or telnet] (Telnet traffic is not allowed) Router(config)#access-list 160 deny icmp any any (All icmp data from any source to any destination is denied) To display ACL Router#show access-lists or Router#show access-list <no> To display ACL applied on interface Router#show ip interface

Example: - Extended ACL Suppose we want to control inbound traffic for our network. ACL should be designed according the following policy. (1) Access to web server (200.100.100.3) is allowed from any source. (2) FTP server (200.100.100.4) should be accessible only from branch office n/w (200.100.175.0/24). (3) ICMP & Telnet should be allowed only from remote pc 200.100.175.80 (4) Any pc can access DNS (200.100.100.8) 200.100.175.x Router

Router

200.100.100.x Router(config)#access-list 130 permit tcp any host 200.100.100.3 eq 80 Router(config)#access-list 130 permit tcp 200.100.175.0 0.0.0.255 200.100.100.4 0.0.0.0 Eq 21 Router(config)#access-list 130 permit icmp 200.100.175.80 0.0.0.0 any Router(config)#access-list 130 permit tcp 200.100.175.80 0.0.0.0 any eq 23 Router(config)#access-list 130 permit udp any host 200.100.100.8 eq 53

Switch port ACL
You can only apply port ACLs to layer 2 interfaces on your switches because they are only supported on physical layer 2 interfaces. You can apply them as only inbound lists on your interfaces, and you can use only named lists as well. Extended IP access lists use both source and destination addresses as well as optional protocol information and port number. There are also MAC extended access lists that use source and destination MAC addresses and optional protocol type information. Switches scrutinize all inbound ACLs applied to a certain interface and decide to allow traffic through depending on whether the traffic is a good match to the ACL or not. ACLs can also be used to control traffic on VLANs. You just need to apply a port ACL to a trunk port. Switch#conf ter Switch(config)#mac access-list extended abc Switch(config-ext-mac)#deny any host 000d.29bd.4b85 Switch(config-ext-mac)#permit any any Switch(config-ext-mac)#do show access-list Switch(config-ext-mac)#int f0/6 Switch(config-if)#mac access-group abc

Lock and Key (Dynamic ACLs)
These ACLs depends on either remote or local Telnet authentication in combination with extended ACLs. Before you can configure a dynamic ACL, you need to apply an extended ACL on your router to stop the flow of traffic through it.

Reflexive ACLs
These ACLs filter IP packets depending upon upper-layer session information, and they often permit outbound traffic to pass but place limitations on inbound traffic. You can not define reflexive ACLs with numbered or standard IP ACLs, or any other protocol ACLs. They can be used along with other standard or static extended ACLs, but they are only defined with extended named IP ACLs.

Time-Based ACLs
In this you can specify a certain time of day and week and then identity that particular period by giving it a name referenced by a task. The reference function will fall under whatever time constraints you have dictated. The time period is based upon the router‟s clock, but it is highly recommended that using it in conjunction with Network Time Protocol (NTP) synchronization. Router#conf ter Router(config)#time-range no-http Router(config-time-range)#periodic <Wednesday|weekdays|weekend> 06:00 to 12:00 Router(config-time-range)#exit Router(config)#time-range tcp-yes Router(config-time-range)#periodic weekend 06:00 to 12:00 Router(config-time-range)#exit Router(config)ip access-list extended time Router(config-ext-nacl)#deny tcp any any eq www time-range no-http Router(config-ext-nacl)#permit tcp any any time-range tcp-yes Router(config-ext-nacl)#interface f0/0 Router(config-if)#ip access-group time in Router(config-if)#do show time-range

Remarks
Remarks are the comments or remarks regarding the entries you have made in both your IP Standard and Extended ACLs. Router#conf ter Router(config)#access-list 110 remark <remark words> permit rahul from admin only to sale Router(config)#access-list 110 permit ip host 172.16.10.1 172.16.20.0 0.0.0.255 Router(config)#access-list 110 deny ip 172.16.10.0 0.0.0.255 172.16.20.0 0.0.0.255 Router(config)#ip access-list extended no_telnet Router(config-ext-nacl)#remark deny all of finance from telnetting to sale Router(config-ext-nacl)#deny tcp 172.16.30.0 0.0.0.255 172.16.20.0 0.0.0.255 eq 23 Router(config-ext-nacl)#permit ip any any Router(config-ext-nacl)#do show run

Cisco Discovery Protocol
This protocol is by default enabled in Cisco devices. It will send periodic update after every one minute on all interfaces. The neighbors will receive this information and store in the CDP neighborship table.

CDP is helpful in troubleshooting or to create documentation of CDP. We can obtain following information about neighbor automatically. (1) Hostname (2) Device type (3) Model/Platform (4) IOS version (5) Local connected interface (6) Remote device connected interface (7) Entry IP address etc. Display CDP status Router#sh cdp To display CDP enabled interfaces Router#sh cdp interface To display CDP neighbors Router#sh cdp neighbor Or Router#sh cdp neighbor detail To disable CDP from device Router#conf ter Router(config)#no cdp run To disable CDP on particular interface Router#conf ter Router(config)#int <type> <no.> Router(config-if)#no cdp enable Router(cobfig-if)#exit To change CDP timers Router#conf ter Router(config)#cdp timer <value> (by default 60 sec) Router(config)#cdp holdtime <value> (by default 180 sec) (Value in seconds)

Wide Area Network

The network that is design for long distance communication is called Wide Area Network. A WAN network uses WAN protocols, WAN interface card to communicate with remote network. WAN

Point-to-Point

Circuit Switching

Packet Switching

Cell Switching ATM Maximum

Leased line ISDN Frame Relay MLLN PSTN X.25 Radio Link For 2 locations Unlimited Maximum Factors to be considered while selecting a WAN technology (1) No. of locations (2) Hours of connectivity (3) Speed (4) Cost (Bandwidth + Distance)

(5) Reliability WAN Encapsulation WAN encapsulation is used to convert a packet into frame and transfer data to WAN links, Different type of encapsulation are designed for different WAN technologies. The general format of WAN encapsulation is: Flag Address Control Data FCS Flag

FH Common WAN Encapsulation Point-to-Point Point-to-Point, Circuit Switch Frame Relay Frame Relay X.25 ISDN ATM

Packet

FT

High level data link control Point-to-Point Protocol Frame Relay Cisco Frame Relay IETF Link Access Procedure Based Link Access Procedure Based for D channel ATM Adaptation layer 5

HDLC PPP

LAPB LAPD AAL5

Point-to-Point WAN technologies
These WAN technologies are used to connect two locations with each other. It is the 24-hour high speed and reliable connectivity. We can setup this WAN technology in three steps: Step 1: - Connect the devices according to topology. Step 2: - Configure Modems. Step 3: - Configure Router. Step 1 Point-to-Point WAN Topology (a) Campus n/w or Drop wire n/w V.35 RS 232 EIA/TIA 530 Modem Line Line 2 wire TP Or 4 wire TP DB-60 Smart Serial Serial Router eth RJ-45 * Distance depends on modems & mostly up to 10-15 kms. Router

(b) Leased line via Service Provided G703 G704 Modem Line Local Loop Line Modem V.35 RS 232, EIA/TIA 530 R SS, DB-60 Modem Mux Exchange Mux Modem

Local Loop

R

(c) Managed Leased Line n/w (MLLN) Exchange

MLLN MUX

MLLN MUX

MLLN Modem

MLLN Modem

Router

Router

(d) Radio Link

V.35

Radio Modem

Antenna

Radio Modem

RS 232 EIA 530 DB-60 Smart Serial Router Router

(e) Radio Link using IDU & ODU Radio Modem ODU UTP or Coaxial Router Radio Modem IDU Radio Modem IDU Router ODU – Out Door Unit IDU – In Door Unit Radio Modem ODU

Line 4 Wire 1 ------2 ------- Loop 1 3 4 ------- Loop2 5 ------ 6 7 8 2 Wire 1 2 3 4 ------- Signal 5 ------6 7 8

Step 2 Configurations of Modems We have to configure various parameters in the modem. There are three different methods to configure these parameters according to Modem. Method1) Configuration of modem using Jumper setting/ Dip switches.

2) Configuration of modem using LCD menu. 3) Configuration of Modem using Console/ Terminal. Step 3 Configuration of Router To configure Router for a Leased line scenario or Point-to-Point n/w, we have to set following parameters: 1) IP addresses 2) IP routing 3) WAN encapsulation

172.16.0.1 192.168.5.1

172.16.0.2 10.0.0.1

In Point-to-Point WAN n/w any type of routing be perform on routers.

WAN Encapsulation
Two routers interfaces in Point-to-Point WAN must required to have same WAN encapsulation. Two types of WAN encapsulation are supported in this type of network. (1) HDLC (2) PPP

HDLC PPP Same Manufacturer

PPP Different Manufacturer By default, Cisco routers will use Cisco HDLC encapsulation. We can change encapsulation by following command: Router#conf ter Router(config)#interface <type> <no> Router(config-if)#encapsulation ppp|hdlc

HDLC High Level Data Link Control HDLC is the modified form of SDLC (Synchronous Data Link Control). SDLC was developed by IBM for router to main frame communication. HDLC is modified for router-to-router communication. Most of manufacturer has developed their proprietary HDLC protocol. So HDLC from one manufacturer is not compatible for other. HDLC encapsulation is designed for Point-to-Point router communication. In HDLC no addressing is required, but still all station address is used in encapsulation. HDLC provides only basic features and error checking for the frame. PPP – Point-to-Point Protocol PPP is an open standard WAN protocol that can be used in Point-to-Point and circuit switching networks. PPP provides various advantages as compared to HDLC. PPP has following special features: (1) Authentication (2) Multi Link (3) Compression (4) Call Back PPP at OSI layer A P S T N Lan, Wan Protocols P DL TCP/IP IPX/SPX PPP HDLC LAPB EE 8023 ARPA Network D A NCP T ------------------A LCP L I -------------------N HDLC Physical Three Phases of PPP (1) Link Control Protocol (LCP) This protocol negotiates the basic feature of PPP. It exchanges the parameter and option to be used with link. LCP supported features are: Authentication, Compression, Multi link & Call back (2) Authentication Phase - optional In this phase authentication is performed with peers with the help of one of the following protocol.

PPP

K

(i) Password Authentication Protocol (ii) Challenge Handshake Authentication Protocol (iii) Microsoft CHAP (iv) Shiva PAP (clear text) (3) Network Control Protocol Phase (NCP) In this phase parameters for routed protocol are established. In NCP, there is one module for each router protocol. IPCP for TCP/IP IPXCP for IPX/SPX CDPCP for CDP etc. Configuring Authentication in PPP Example: Router 1 S0

Router 2 S1

Router 1 Router#config ter Router(config)#int serial 0 Router(config-if)# encapsulation ppp Router(config-if)# ppp authentication chap Router(config-if)#ip address 10.0.0.1 255.0.0.0 Router(config-if)#no sh Router(config-if)#exit Router(config)#hostname chd Router(config)#username ldh password net123 Router(config)#exit Router 2 Router#config ter Router(config)#int serial 1 Router(config-if)#encapsulation ppp Router(config-if)#ppp authentication chap Router(config-if)#ip address 10.0.0.2 255.0.0.0 Router(config-if)#no sh Router(config-if)#exit Router(config)#hostname ldh Router(config)#username chd password net123 Router(config)#exit Configuring Compression in PPP In PPP, one of the following three protocols can be used for compression (1) Stac (2) Predictor (3) Microsoft Point-to-Point Compression Router#config ter Router(config)#interface <type> <no> Router(config-if)#encapsulation ppp Router(config-if)#compress <Stac|MPPC|Predictor> Router(config-if)#exit

To display Compression Router#show compress PPP debug commands Router#debug ppp error Router#debug ppp authentication Router#debug ppp negotiation To display PPP status Router#show interface LCP Open LCP Closed LCP Request sent LCP Listen IPCP Open IPCP Closed CDPCP Open CDPCP Closed

Circuit Switching

In Circuit Switching, all users are connected to the Circuit Switching. Exchange cloud depending upon user request. A circuit is established between two locations and then data is transferred. A signaling protocol is used to establish the connectivity then data is transferred with the help of protocol used Point-to-Point WAN. Examples of Circuit Switching are: ISDN (Integrated Services Digital Network) PSTN (Public Switched Telephone Network)

Integrated Services Digital Network
ISDN is the high-end circuit switching technology, which is designed for voice, data and video. ISDN is the time division multiplexing technology, in which multiple channels are used to transfer rate.

ISDN

PRI

BRI 2 B Channels 1 D Channel

E1

T1

30 B Channels 1 D Channel

23 B Channels 1 D Channel

B Channel (Bearer Channel) This channel carries data using data encapsulation.

D Channel (Data Channel) This channel carries signal using signaling protocol. Time Division Multiplexing in ISDN BRI B1 S1 B2 S D Ch S B1 S B2 S --

T B1 B2 D Ch S ------------------------64 kbps 64 kbps 16 kbps 48 kbps

ISDN BRI Topology ISDN Cloud TE 1 S NT 2 S TE 2 NT 1 NT 2 TE 1 TE 2 TA R TA T NT 1 U 2 wire

Network Termination 1 Send/Receive ISDN BRI Signals Network Termination 2 Share ISDN between multiple users Terminal Equipment 1 ISDN compatible device Terminal Equipment 2 Non-ISDN device Terminal Adapter Connects ISDN line with Non-ISDN device

Topology 1: - Voice ISDN Phone 1 ISDN Phone 2 4 NT 1 4 2 wire ISDN Cloud

Topology 2: - Voice

Phone 1 TA NT 1 ISDN Cloud

Phone 1

Topology 3: - Voice + Data

PC

USB Serial

TA

NT 1

ISDN Cloud

Ph 1

Ph 2

Install TA in Pc, similar to External modem installation. Use “Dialup Networking” to connect Remote location. Topology 3: - Data Router ISDN BRI S/T NT 1 ISDN Cloud

Router NT 1

ISDN BRI U

ISDN Cloud

Configuring ISDN BRI We will configure ISDN BRI for following two scenarios: (1) ISDN Branch office to Branch office connectivity. (2) ISDN Branch office to ISP Connectivity.

ISDN Branch office to Branch office

Switch type Basic-net3 306306

ISDN Cloud ISDN Switch ISDN Switch

Switch type Basic-ni 288288

192.168.10.5 R1 Encapsulation - PPP Authentication - CHAP Hostname R1 - Chd Hostname R2 - Del Password – net123 Routing - Static

192.168.10.6 R2

172.16.0.1

172.30.0.1

172.16.X.X Demand Dial Routing Steps: (1) Specify interesting Topic (2) Configure Route (3) Dial to Remote location (4) Negotiate Parameters (5) Transfer Data (6) Monitor interesting traffic (7) Disconnect the call R1 Router#config ter Router(config)#int eth0 Router(config-if)#ip address 172.16.0.1 255.255.0.0 Router(config-if)#no sh Router(config-if)#exit Router(config)#ip route 172.30.0.0 255.255.0.0 192.168.0.6 Router(config)#ip route 192.168.0.6 255.255.255.255 BRI 0 Router(config)#dialer-list 5 protocol ip permit Or Router(config)#access-list 20 deny 172.16.0.32 0.0.0.15 Router(config)#access-list 20 deny 172.16.0.20 Router(config)#access-list 20 permit any Router(config)#dialer-list 8 protocol ip list 20 Router(config)#isdn switch-type basic-net3 Router(config)#hostname Chd

172.30.X.X

Router(config)#username Del password net123 Router(config)#int bri 0 Router(config-if)#encapsulation ppp Router(config-if)#ppp authentication chap Router(config-if)#ip address 192.168.10.5 255.255.255.0 Router(config-if)#dialer map ip 192.168.10.6 name Del 288288 Router(config-if)#dialer hold-queue 10 (no. of packets range 1 – 100) Router(config-if)#dialer-group 8 Router(config-if)#dialer idle-timeout 180 Router(config-if)#no sh (if no response from the dialer connection break) Router(config-if)#exit R2 Router#config ter Router(config)#int eth0 Router(config-if)#ip address 172.30.0.1 255.255.0.0 Router(config-if)#no sh Router(config-if)#exit Router(config)#ip route 172.16.0.0 255.255.0.0 192.168.0.5 Router(config)#ip route 192.168.0.5 255.255.255.255 BRI 0 Router(config)#dialer-list 5 protocol ip permit Or Router(config)#access-list 30 deny 172.30.0.32 0.0.0.15 Router(config)#access-list 30 deny 172.30.0.20 Router(config)#access-list 30 permit any Router(config)#dialer-list 8 protocol ip list 30 Router(config)#isdn switch-type basic-net3 Router(config)#hostname Del Router(config)#username Chd password net123 Router(config)#int bri 0 Router(config-if)#encapsulation ppp Router(config-if)#ppp authentication chap Router(config-if)#ip address 192.168.10.6 255.255.255.0 Router(config-if)#dialer map ip 192.168.10.5 name Chd 306306 Router(config-if)#dialer hold-queue 10 Router(config-if)#dialer-group 8 Router(config-if)#dialer idle-timeout 180 Router(config-if)#no sh Router(config-if)#exit ISDN Branch office to ISP Internet

E1/T1 ISDN Cloud RAS R

Basic-net3

383843

NT1

DNS Router ISP Parameter Ph no. Username Password ISDN Service Provider Switch Type Router#config ter Router(config)#int eth 0 Router(config-if)#ip address 10.0.0.1 255.0.0.0 Router(config-if)#no sh Router(config-if)#exit Router(config)#ip route 0.0.0.0 0.0.0.0 bri 0 Router(config)#dialer-list 7 protocol ip permit Router(config)#isdn switch-type basic-net3 Router(config)#int bri 0 Router(config-if)#ip address negotiated Router(config-if)#encapsulation ppp Router(config-if)#ppp authentication chap pap call in Router(config-if)#ppp pap sent-username <ispuser> password <word> Router(config-if)#ppp chap hostname <ispuser> Router(config-if)#ppp chap password <word> Router(config-if)#dialer string 383843 Router(config-if)#dialer-group 7 Router(config-if)#dialer-idle timeout 180 Router(config-if)#dialer hold-queue 10 Router(config-if)#no sh Router(config-if)#exit NAT for ISDN dialup ISP connectivity Router#conf ter Router(config)#int eth 0 Router(config-if)#ip nat inside Router(config-if)#int bri 0 Router(config-if)#ip nat outside Router(config-if)#exit Router(config)#access-list 50 permit any Router(config)#ip nat inside source list 50 interface bri 0 overload Testing and Troubleshooting of ISDN (i) To display present active call

Authentication Accounting Authorization

Router#sh isdn active (ii) To display history of calls Router#sh isdn history (iii) To display ISDN status Router#sh isdn status Layer1 = Active Layer2 Multiple frame established Layer3 1 Active layer call or 2 Active layer 3 call (iv) To place ISDN test call Router#isdn call interface <type> <no> <phone no> (v) To disconnect a call Router#isdn disconnect interface bri 0 <no> all Debug Commands Interesting traffic or dialer Router#debug dialer events Router#debug dialer packets ISDN problem Router#debug isdn events Router#debug isdn 2921 Router#debug isdn 2931 PPP problem Router#debug ppp negotiation Router#debug ppp authentication Router#debug ppp error Configuring ISDN multi-link An ISDN multiple channels can be combined to dial the same location and transport data for this purpose. We will use PPP multi-link and Cisco bandwidth on demand configuration. Router#conf ter Router(config)#int bri 0 Router(config-if)#ppp multilink Router(config-if)#dialer load-throshold <value> either (inbound or outbound) 1-255 Router(config-if)#exit Error code at cisco.com

Packet Switching

Packet Switching is the wan technology in which all devices are connected to the packet switching exchange. The devices will request packet switching exchange to create a virtual connection then data is transferred over the virtual connection. It is possible to create more than one virtual connection and transfer data over them one by one. Example of Packet Switching Technology are: (1) X.25 (2) Frame Relay Frame Relay Frame Relay is the Packet switching technology in which virtual connections are established. The frame relay supports only permanent virtual connections. Frame used special addresses called DLCI to create common and virtual connections.

Frame Relay Topology

FR SW

4 wire Tp Line

FR Modem Line Local loop

V.35 232 530

FR Modem

V.35, RS232, EIA 530

DB-60, Smart Serial Router Virtual Circuit In packet switching technology there are two types of virtual circuits: (1) Switched Virtual Circuit (SVC) (2) Permanent Virtual Circuit (PVC) Switch Only PVC is supported in Frame Relay technology.

Frame Relay DLCI DLCI stands for Data Link Control Identifier. It is used for addressing purpose. In frame Relay Encapsulation, Virtual Circuits are established and data is transferred on the basis of DLCI. DLCI addresses are different from general addressing scheme. One DLCI address provided for each virtual circuit that we want to create. DLCI range 16 - 1017

Frame Relay Encapsulation
Frame Relay use special type of Encapsulation, Which is specifically designed for this technology. There are two encapsulations are available: (1) Frame Relay Cisco (2) Frame Relay IETF (Internet Engineering Task Force)

R Cisco FR IETF FR Cisco

R

Cisco

R IETF FR Non Cisco

R

any

Frame Relay Local Management Interface LMI are the keepalive signals, which are used to keep the virtual circuit up and running. LMI are exchange between frame relay switch and router. We have to set same LMI on router as specified by the service provider. There are three types of LMI that we can use (1) CISCO (2) Q933a (3) ANSI R1 Router#config ter Router(config)#int eth0 Router(config-if)#ip address 172.16.0.1 255.255.0.0 Router(config-if)#no sh Router(config-if)#exit Router(config)#ip route 172.30.0.0 255.255.0.0 192.168.10.2 Router(config)#int serial 0 Router(config-if)#encapsulation frame-relay Router(config-if)#frame-relay lmi-type cisco Router(config-if)#ip address 192.168.10.1 255.255.255.0 Router(config-if)#frame-relay interface-dlci 300 Router(config-dlci)#exit Router(config-if)#frame-relay map ip 192.168.10.2 300 Router(config-if)#no sh Router(config-if)#exit R2 Router#config ter Router(config)#int eth0 Router(config-if)#ip address 172.30.0.1 255.255.0.0 Router(config-if)#no sh Router(config-if)#exit Router(config)#ip route 172.16.0.0 255.255.0.0 192.168.10.1

Router(config)#int serial 0 Router(config-if)#encapsulation frame-relay Router(config-if)#frame-relay lmi-type cisco Router(config-if)#ip address 192.168.10.2 255.255.255.0 Router(config-if)#frame-relay interface-dlci 400 Router(config-dlci)#exit Router(config-if)#frame-relay map ip 192.168.10.1 400 Router(config-if)#no sh Router(config-if)#exit Configuring Frame Relay Point to Point connectivity

Cisco

FR SW SW

ANSI

M

M

300 for R2 encap: - Cisco FR M

400 for R1

M

192.168.10.1 R1 172.16.0.1

192.168.10.2 R2 172.30.0.1

Network Address Translation
NAT is the feature that can be enable in a Router, Firewall or a Pc. With the help of NAT, we are able to translate network layer addresses that are IP addresses of packets. With Port Address Translation, we are also able to translate port numbers present in transport layer header.

Advantage of NAT
There are two reasons due to which we use NAT: (1) Conserve Live IP address On Internet, there are limited no of IP addresses. If our Clients wants to communicate on Internet then it should have a Live IP address assigned by our ISP. So that IP address request will depend on no. of PCs that we want to connect on Internet. Due to this, there will be a lot of wastage in IP addresses. To reduce wastage, we can share live IP addresses between multiple PCs with the help of NAT. (2) NAT enhances the network security by hiding PC & devices behind NAT.

NAT Terms:
Inside Interface: The interface connected to inside local network Outside Interface: The interface connected to outside internet. Inside Local: IP address assigned to local network by administrator from Private IP range. Inside Global: IP address assigned by ISP for Local LAN from Public IP range.

Working of NAT & PAT

10.0.0.5

Internet 10.0.0.6 Switch 10.0.0.1 NAT 200.100.100.12

10.0.0.7

10.0.0.8 10.0.0.5 200.100.100.12 1080

10.0.0.6 200.100.100.12 1085

10.0.0.7 200.100.100.12 1024

Port Translation 1100

10.0.0.8 200.100.100.12 1024

Types of NAT
Static NAT This NAT is used for servers in which one Live IP is directly mapped to one Local IP. This NAT will forward on the traffic for the Live IP to the Local PC in the n/w. Static NAT 200.1.1.5 = 192.168.10.6 Router Live 200.1.1.5 Internet

Local 192.168.10.6 Port Based Static NAT This NAT is also used for servers. It provides port-based access to the servers with the help of NAT.

200.1.1.5:80 -> 192.168.10.6 200.1.1.5:53 -> 192.168.10.7 Router

Internet

Web 192.168.10.6

DNS 192.168.10.7

Dynamic NAT using Pool Dynamic NAT is used for clients, which want to access Internet. The request from multiple client IPs are translated with the Live IP obtained from the Pool. It is also called Pool Based Dynamic NAT. Pool => 200.1.1.8 – 200.1.1.12/28

Local address => 172.16.X.X Except => 172.16.0.5 172.16.0.6 172.16.0.7 Router

Internet

Web Server 172.16.0.5

DNS Full access 172.16.X.X 172.16.0.6 172.16.0.7

Pool allotted => 200.1.1.0 – 15/28 Server Static => 200.1.1.3 = 172.16.0.7 Port Based Static NAT 200.1.1.4:53 = 172.16.0.6 200.1.1.4:80 = 172.16.0.5 Client Dynamic NAT Pool => 200.1.1.8 – 200.1.1.12/28 Local address => 172.16.0.X Configuring NAT Router#conf ter Router(config)#int serial 0 Router(config-if)#ip nat outside Router(config-if)#int eth 0 Router(config-if)#ip nat inside Router(config-if)#exit Router(config)#ip nat inside source static 172.16.0.7 200.1.1.3 Router(config)#ip nat inside source static tcp 172.16.0.5 80 200.1.1.4 80 Router(config)#ip nat inside source static udp 172.16.0.6 53 200.1.1.4 53 Router(config)#access-list 30 permit any Router(config)#ip nat pool abc 200.1.1.8 200.1.1.12 netmask 255.255.255.240 Router(config)#ip nat inside source list 30 pool abc overload

To display NAT translation Router#sh ip nat translations (after ping any address, it shows ping details) To clear IP NAT Translation Router#clear ip nat Translation *


				
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