WAN ass01 by huangyuarong

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                                     Introduction




       T-carrier system was the first successful system which supported digitized voice and

data transmission. Originally transmission rate of 1.544Mbps in T1 line, which is commonly

use today by Internet Service Provider (ISP) to connect to the Internet. There is another level,

which is T3 line that could provide 44.736 Mbps. Both are most popular T-carriers.


       T1 also spell T-1, stands for Trunk Level 1, which is a digital transmission link that

provide always-on broadband connections, give us ability to consistently communicate and

exchange data. It is a standard for digital transmission in North America-the United States

and Canada while in Europe is E1 and E3. Besides, it does much faster than standard dial-up

and guaranteed 99.99% uptime with increased security. T1 is symmetrical connection, which

means both downloads and uploads speeds are the same, could be up to 1.5Mbps. Due to the

dedicated links of T1, user can have access to the full amount of bandwidth. However, actual

performance is depending on the numbers of users online at the time. A single T1 connection

supports dozens to hundred of users and fast enough for 24 simultaneous users.


       T1 line can carry 24 digitized voice channels, and being used for telephone

conversations. It is provisioned with service level agreement (SLA) which guarantees the

reliability of the Internet Service, which protect business by making access providers to pay

penalties to customer in case if the downtime exceeds a specific total. This is the standard for

quality high-speed Internet access. On the other hand, we are hard to get an SLA on DSL

access because the sensitivity to distance from company to ISP’s central office, which often

coupled with low quality wiring, make it hard to maintain the guaranteed uptime.



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       T1 line is obviously more expensive than DSL. In fact, both actual connection speeds

are very similar. However, T1 could provide more reliable connection and users are paying

for the guaranteed uptime. DSL and T1 are intended for different applications but both are

digital services. DSL is dividing into symmetrical and asymmetrical. Asymmetrical Digital

Subscriber Line (ADSL) is suggested residential use, which it’s uploads and downloads

speeds are different. Download speed tends to be faster than upload. DSL is using Discrete

Multitone Modulation (DMT) technology that adapts itself to the condition of the telephone

line it shares. The speed you get depends on how far away you are from the equipment

providing the DSL service, and the amount of noise and interference on the line. T1 is a

synchronous time division multiplexed system, which it’s not only on all the time, but

sending something all the time an expecting to received something all the time. It use framing

bits to keep both ends connections synchronized to define the time slots. This allows T1 lines

to carry standard switched telephone calls as well as VoIP phone. T1 can carry 24 telephone

lines to support a business PBX system. Each phone call occupies a well defined time slot in

the T1 transmission.


       While T3 line is at the equivalent speed of 28 T1 lines, a dedicated T3 point-to-point

connection is frequently used by larger businesses for transmission of very large files, use

high-quality video conferencing, or query the contents of large databases. T3 lines are also

used by many ISPs and businesses as the backbone for large networks. They may be the

artery through which a large organizations' data flows.




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     The implementation of T1&T3 technology seleted is
                                    optimux 45 L



                   What is optimux 45L? Who is optimux 45L?

     Optimux 45L is one kinds of technology device which can use to reduce our monthly

leased line expenses, it is choosing because it contains the technology of T1&T3. Feature-

packed products at reasonable prices provide a quick return on investment. Optimux-45L

provides a simple, flexible and cost-effective solution for transporting multiple T1 and E1

signals at distances of up to 110 km (68 miles). Besides that, it integrates up to 28T1, 21 E1,

or any combination of T1 and E1 channels, over a single 45 Mbps data link. This provides an

easily configurable solution, flexible enough to meet the specific requirements of a broad

range of an application. Two Optimux-45L units can be connected over a single fiber link,

using either WDM (Wavelength Division Multiplexing) or another bidirectional technology,

thus saving on fiber usage.


    Optimux-45L is provided with two 64-pin Telco connectors for balanced or unbalanced

tributary ports. Optimux-45L transmits the clock of each of the E1/T1 channels

independently. The setup, control and diagnostics can be performed using an ASCII terminal

connected via the DB-9 control port. Alternatively, these functions can be performed using a

Telnet or a RAD view application, connected to the dedicated Ethernet management port.

Besides that, it is interoperable with RAD’s Optimux-45, FOM-T3 and FOMi-T3 devices.

RAD view, RAD’s SNMP management application software provides a user-friendly GUI for

Optimux-45L configuration, monitoring and management. RAD view applications are

available for either Windows or UNIX-based HP Open View environments. To facilitate

system diagnostics, Optimux-45L features LED status indicators, AIS alarm generation and

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recognition, dry contact closure upon link failure and diagnostic loopbacks on the E1/T1 and

T3 links. Optimux-45L is available as a compact 1U high unit that can be mounted in a 19-

inch (ANSI) or ETSI rack.


         Optimux 45L is common use by some business company to help them in their

telecommunication activities and transferring process like transfer file and email. Besides that

the small organization like school also uses it to control the speed of network in their school.


   The features of optimux 45L are as the below:


      Multiplexes up to 28 T1 or 21 E1 channels into a single T3 data link

      Supports a combination of T1 and E1 channels

      Transmission over coax or fiber optic cable

      Supports single mode fiber, multimode fiber and single fiber (WDM)

      Range of up to 110 km(68 miles)

      Conforms to ITU G.703,G.747, G.823, G.824,ANSI T1.107, T1.404,RFC2495,

       RFC2496

      Optional second power

      supply provides redundancy



   The picture of OPTIMUX 45L is:




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                      When, why, and how is it Implemented?


   One example where OPTIMUX 45L is it is already used by some small or large business

company to transfer data. By using optimux 45L, we can direct use the technology of T1 and

T3 which are commonly used by businesses because they offer very fast data transfer rates.

This is appealing to businesses that need to transfer large amounts of data each day.

Additionally, T lines provide very reliable forms of Internet access, with “always on”

capability and very few incidences of lost Internet connections. In terms of speed, T1 lines

operate at 1.5 Mbps, and T3 lines operate at 44.6 Mbps. In other words, T3 lines are about 30

times faster than T1. These high speeds are very useful for heavy Internet traffic situations as

well as for situations in which a network must be accessed by a larger number of users. A T1

line operating at full capacity can accommodate up to 24 users working at 64 Kbps.


       If our businesses are require very fast broadband so the Internet connections will

choose T3 lines as they are among the fastest connections available today. T3 lines offer

enough bandwidth to host multiple high-traffic web sites as well as “always on” access for

organizations, schools and other groups that require hosting for high-volume web sites.T line

broadband Internet connections are very widely used and are available in almost every region.

These broadband Internet connections are currently among the most common way that

companies connect their LAN to the rest of the world. While the majority of everyday

Internet users will not require the benefits that T1 and T3 broadband Internet connections

provide, both of these connections do allow businesses with multiple users to talk on the

phone and use the Internet at the same time using the same phone line. Also, multiple users

can download files at a very fast speed. In addition to very fast Internet access, very high

bandwidth and reliability, T1 and T3 connections also offer increased security.




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        The technology of T1 & T3 also widely use in telecommunication. A T1 line is a

wholesome digital line. Conversations are converted from sound to digital prior to being

transmitted on the T1 line. The T1 line can tackle 24 simultaneous voice calls. 24

simultaneous calls can serve well over 100 employees of an organization depending on their

calling pattern. At times, one of the 24 lines is dedicated to caller ID. This line is generally

connected to a computer which looks up customer records which are routed to the computer

of the person taking the call. A T1 line can handle a high speed internet connection speed of

1.544mbps.



     On the other hand T3 in telecommunication is known as a super high speed connection

which can transmit data at the rate of 45 million bits per second. A T3 line represents a

bandwidth equal to approximately 672 regular voice grade telephone lines. Besides that it is

wide enough to transmit full motion, real time video and a very large database over a hectic

network. In general, a T3 line is installed as a major networking channel for large

corporations and educational institutes with high volume network traffic. Next, T3 line is also

a wholesome digital line. It is alike to 28 T1 lines or 672 POTOS lines. The T3 line can

tackle 672 simultaneous voice calls or can provide a high speed internet connection of

44.736 Mbps as an integrated service it can handle a combination of lesser voice calls

and can provide a high speed internet connection. From here we can conclude that T3

is       generally     used     by    a    high     end     data    and     voice     customer.




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The application of the optimum 45L is as the below diagram:

   a) Point-to-Point Application




   b) Optimux-45L Operating opposite FOM-T3




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The below are some examples of optimux device:




                                       OPTIMUX-155X



Vendor         :   RAD Data Communications


Function       :   Fiber mux extends up to 84xT1s or 3xT3s


Infrastructure:    Fiber, coax, OC-3


Features      :    Redundant uplink and power supply, management




                                        OPTIMUX-45



Vendor         : RAD Data Communications


Function       : M13 multiplexer extends up to 28xT1s or 21 E1s


Infrastructure: Fiber, coax


Features      : Redundant uplink and power supply, management




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                                      OPTIMUX-106



Vendor        : RAD Data Communications


Function      : Fiber multiplexer extends 4 x T1s and Fast Ethernet


Infrastructure: Fiber


Features      : Redundant uplink and power supply, management




The below is some example of connection between optical fiber and optimux


by Using a T1 Multiplexer or T1/T3 Modem:




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                Common WAN Implementation Issues




       T1 lines use standard telephone companies and provisioned over fiber optic cables or

2 pair of ordinary telephone wires.T1 service is often available in rural and urban areas which

are not serviced by DSL or Cable. T1 is divided into Internet Service and Voice Service.


       In Internet Service, T1 has super high-speed Internet Access which can allocate all 24

channels to data, and give a 2-way connection at 1.544Mbps. T1 has been defined as a very

reliable high speed internet connection. Whereas T1 Voice Service with 12-24 phone lines is

normally rely on DS-1 voice service. There is 24 DS-0 circuits on a single T-1 circuit and

these 24 phone lines are then connected to local or long distance carrier at the same time.


       T1 line provides guaranteed bandwidth, since the line is not shared with other users.

The T1/DS1 standard is used in the North American and Japanese marketplaces. A T1, or

DS1 line, is a private dedicated line that goes directly from your office or business to your

Internet Service Provider (ISP), providing transmission at 1.544 Mbps, roughly 60 times more

data than a normal residential modem. It is also extremely reliable, much more reliable than

an analog modem.


       There are plenty types of T1 connections, which includes full T1, T1 Data Service,

Voice T1, Integrated T1 (called Channelized T1), Fractional T1, Point-to-Point T1, Burstable

T1 and Bonded T1. Each of these is selected based on user voice or data needs. Bonded T1

lines will double, triple or quadruple the capability. For an Internet service provider or a

fairly large office, then T3 is more compatible as T3 runs at about 45 Megabits per second or




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the equivalent of 28 T1 lines which means 672 channels. If that's not enough, there are

optical carrier services that can surely satisfy the need for speed.


        However, T1 lines almost consist of common features, which is highly reliable. This

is because it is a dedicated link between companies (LAN) or from company to Internet

Service Provider (ISP),which means it is set up as dedicated point to point connections

between business locations. It is using synchronous time division multiplexed system, which

is always-on by sending and receiving something all the time.


       T1 line multiplexes or aggregates 24 of these DS0 channels into a DS1 with a total

bandwidth of 1.536 Mbps. But a T1 line runs at 1.544 Mbps. The extra 8 Kbps represents the

framing bit that T1 adds to each group of 24 DS0 channels to ensure that the CSU (channel

service unit) at the other end of the line knows where to demultiplex the frame of 24 DS0s.

With synchronous lines like T1, framing bits are needed to keep the sending and receiving

ends tightly synchronized.




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        In more detail, a voice channel was selected to be at 64 Kbps. 24 of these channels is

a composite of 1.536 Mbps, not 1.544 Mbps. After a byte (8 bits) of data is sent from each

channel (24 * 8 = 192 bits) there is an extra bit used for synchronizing, which is Frame bit.

Hence 193 bits are sent and this increase of 1 bit per 192 causes the speed to increase to 1.544

Mbps.


        As a conclusion, we find out that T1 lines are highly reliable connections compared to

others. Although it is eight to ten times more expensive than DSL or cable modem, but due to

its dedicated links with the application of synchronous time division multiplexed system,

which provides its always-on feature that highly increased it’s availability and reliability.




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                                       Conclusion



       As the conclusion, we can summarize the technology of T1& T3 has many advantages.

T1 line provides the equivalent speed of 24 dial-up modem connections, or 12 ISDN

connections. It's intended for small- or medium-sized companies that require a high-speed,

stable connection between their network and the Internet and that frequently transmit or

receive large amounts of data or large data files (such as large graphic or audio files). T1 lines

can also host Voice over IP (VoIP) telecommunications. Besides that we also can dedicate T3

Service where the equivalent speed of 28 T1 lines, a dedicated T3 point-to-point connection

is frequently used by larger businesses to transmit very large files, use high-quality video

conferencing, or query the contents of large databases. T3 lines are also used by many ISPs

and businesses as the backbone for large networks. They may be the artery through which a

large organizations' data flows.


     Although there are many advantages of T1 & T3, but still has some user not used this

technology because nowadays there has many type of technology in the market where these

technologies are most ease to use, cheaper and contain most function than T1& and T3 so the

competition between the technology is difficult for users to choose the suitable technology.

Beside that, we need to waste some money to dedicated T1 & and T3, so this is why it not

suit for some people. Besides that, we also difficult to make a decision whether choose T1 or

T3 in our application.


     Following is the way how to choose either is T1 or T3 in our business. Normally T1

circuit is dedicated and is designed to be used by businesses in order to be able to run not

only the data applications but also the voice applications that are necessary for business. We

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also can conclude that to dedicated T1 is the best choice if compare to T3, if our business

needs reliable, high-speed connectivity, with high capacity and an economical leased line

service because T1 can provides us with up to 1.544 Mbps of bandwidth over a non-shared,

non-fractional and "always on" leased line. It also can help us to transfers mammoth graphics

and data files in just seconds.


    Other than that, by using T1 our businesses can take advantage of the ability to transmit

large files, gain quick access to company data, and faster Web browsing and e-mail

communication with large attachments. Enhance the Connection with add-on integrated

services such as: Video Conferencing, Voice over IP, and the Remote Monitoring System.

Utilizing a dedicated T1 for our network increases productivity and reduces our overall

business efforts and time, while gaining a competitive advantage. For small businesses that

have grown past a DSL connection and for most regular businesses that are not data and

voice service intensive a T1 connection works perfectly. But if the technology is used by the

schools, larger businesses or businesses that deal heavily in voice and data services are

probably going to want to go with a T3 line because of load. It can be used for data or voice

or can even be configured to handle both. In order to determine which the best configuration

is for us consider what our current data and voice usage is and then compare.

     We need to waste some money to dedicated T1 & and T3, so this is why it not suit for

some people. For the future, we can try to create the other new technology or improve the T1

& T3 which can create directly by the users within lower budget. T1&T3 technology are

complexity because it need the help of technical people when face with the problem, it may

let us delay on our application and waste time. Besides that we also we can say that T1&T3

are not alone in the world of technological advancement. Its competitors are numerous and

formidable. However, they have their own advantages and disadvantages. Therefore, the right



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technology must be chosen according to the network usage, application and specified what

the users need for their application and the most importance is the budget of that technology




                                      References



       http://computer.howstuffworks.com/question372.htm

       http://www.webopedia.com/TERM/T/T_3_carrier.html

       http://www.dcbnet.com/notes/9611t1.html

       http://www.nac.net/enterprise/Dedicated.asp?page=t1t3oc3

       http://en.wikipedia.org/wiki/T-carrier

       http://www.yourdictionary.com/hacker/t1-and-t3

       http://www.wisegeek.com/what-is-a-t1-line.htm




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