Modul Pelatihan CCNA 9

Document Sample
Modul Pelatihan CCNA 9 Powered By Docstoc
					TCP/IP Protocol Suite and IP Addressing
Semester 1 – Module 9
Module Objectives:         List and describe the functions of each layer of the TCP/IP model Compare the OSI model and the TCP/IP model Describe the function and structure of IP addresses Understand why subnetting is necessary Explain the difference between public and private addressing Understand the function of reserved IP addresses Explain the use of static and dynamic addressing for a device Understand how dynamic addresses can be assigned with RARP, BootP, and DHCP  Use ARP to obtain the MAC address to send a packet to another device  Understand the issues related to addressing between networks

About TCP/IP
• Created by DoD • Standard on which the Internet is based

Application Layer
• Handles high-level protocols, representation, encoding, and dialog control • Common Protocols:
– File Transfer Protocol (FTP) –reliable, connection-oriented service that uses TCP – Trivial File Transfer Protocol (TFTP) – connectionless service that uses the User Datagram Protocol (UDP). – Network File System (NFS) – a distributed file system protocol suite developed by Sun Microsystems that allows file access to a remote storage device such as a hard disk across a network. – Simple Mail Transfer Protocol (SMTP) – administers the transmission of e-mail – Telnet – Telnet provides the capability to remotely access another computer. – Simple Network Management Protocol (SNMP) –provides a way to monitor and control network devices. SNMP is also used to manage configurations, statistics, performance, and security. – Domain Name System (DNS) – translates domain names and publicly advertised network nodes into IP addresses.

Transport Layer
• Provides a logical connection between a source host and a destination host • Provides end-to-end control and reliability as data • Segment and reassemble data sent by upper-layer applications into the same data stream, or logical connection, between end points • The functions of TCP and UDP are as follows:
– Segment upper-layer application data – Send segments from one end device to another

• The functions of TCP are as follows:
– Establish end-to-end operations – Provide flow control through the use of sliding windows – Ensure reliability through the use of sequence numbers and acknowledgments

Internet Layer
• Selects the best path through the network for packets to travel • The following protocols operate at the TCP/IP Internet layer:
– IP provides connectionless, best-effort delivery routing of packets. – Internet Control Message Protocol (ICMP) provides control and messaging capabilities. – Address Resolution Protocol (ARP) determines the data link layer address, or MAC address, for known IP addresses. – Reverse Address Resolution Protocol (RARP) determines the IP address for a known MAC address.

• IP performs the following operations:
– Defines a packet and an addressing scheme – Transfers data between the Internet layer and network access layer – Routes packets to remote hosts

Network Access Layer
• Allows an IP packet to make a physical link to the network media • Drivers for software applications, modem cards, and other devices operate at the network access layer • Map IP addresses to physical hardware addresses and encapsulate IP packets into frames

• The OSI and TCP/IP models have many similarities:
– Both have layers. – Both have application layers, though they include different services. – Both have comparable transport and network layers. – Both use packet-switched instead of circuit-switched technology. – Networking professionals need to know both models.

• Here are some differences of the OSI and TCP/IP models:
– TCP/IP combines the OSI application, presentation, and session layers into its application layer. – TCP/IP combines the OSI data link and physical layers into its network access layer. – When the TCP/IP transport layer uses UDP it does not provide reliable delivery of packets. The transport layer in the OSI model always does.

IP Addressing
• 32-bit sequence of ones and zeros • written as four decimal numbers separated by periods • 11000000.10101000.00000001.00001000 • 11000000.10101000.00000001.00001001

Binary Conversions
• 1 and 0 • 256 possible numbers, with 255 being the highest • 128+64+32+16+8+4+2+1 = 255 • Convert 193 to binary…

• Broken into two parts
– Network and Host

• hierarchical address - contains different levels • divided into classes
– A - 0 - 127, 127 is reserved…for what? (0) – B - 128 – 191 (10) – C - 192 – 223 (110) – D - 224 – 239, used for multicast (1110)

Reserved IP Addresses
• Network Address
– All 0’s in host portion
• • •

• Broadcast Address
– All 1’s in host portion
• • •

Public & Private Addresses
• Public
– Unique – Public IP addresses must be obtained from an Internet service provider (ISP) or a registry at some expense

• Private
– private networks that are not connected to the Internet may use any host addresses, as long as each host within the private network is unique

• method of managing IP addresses • to use the subnet mask to divide the network and break a large network up into smaller, more efficient and manageable segments, or subnets • borrows bits from the host field and designates them as the subnet field • maximum number of bits that can be borrowed can be any number that leaves at least two bits remaining, for the host number

• uses 128 bits rather than the 32 bits currently used in IPv4 • uses hexadecimal numbers to represent the 128 bits • provides 640 sextrillion addresses • assigned to interfaces, not nodes • written in hexadecimal, and separated by colons

Obtaining an IP Address
• IP addresses are the most commonly used addresses for Internet communications • Static
– small, infrequently changing networks – computer, printer, or server on the intranet

• Dynamic • No two interfaces can have the same IP address

Reverse Address Resolution Protocol (RARP) • associates a known MAC addresses with an IP addresses • allows devices to make a request to learn its IP address • devices using RARP require that a RARP server be present on the network to answer RARP requests

• bootstrap protocol • operates in a client-server environment • only requires a single packet exchange to obtain IP information • packets can include the IP address, as well as the address of a router, the address of a server, and vendor-specific information • not designed to provide dynamic address assignment • Static database

• Dynamic host configuration protocol • allows a host to obtain an IP address dynamically • entire network configuration of a computer can be obtained in one message • Adds mobility

Address Resolution Problems
• communications within a LAN segment require two addresses • needs to be a way to automatically map IP to MAC addresses • too time consuming for the user to create the maps manually • the IP and MAC addresses are needed for both the destination host and the intermediate routing device

• stored in RAM memory • each device on a network maintains its own ARP table • Table built two ways:
– Learning from Source Addresses – ARP Requets

9.2.7 Lab Exercise: IP Addressing Basics 9.3.5 Lab Exercise: DHCP Client Setup 9.3.7 Lab Exercise: Workstation ARP

Shared By: