How Does a Token Ring Work

By: Roberto Bell

Token Ring is a type of a local area network (LAN) technology first thought out by an IBM developer, Olof Söderblom, in the 1960s. Its US patents were first credited in 1981 and was later promoted by IBM throughout the early 1980s. Then, it was popularized by IBM when its Token Ring architecture was founded on active multi-station access units (MSAUs or MAUs) and the IBM Structured Cabling System. The Institute of Electrical and Electronics Engineers also standardized the Token Ring as IEEE 802.5. Although very successful in its early days, with the introduction of 10-BASE-T (Ethernet) and the EIA/TIA 5638 cabling standard, its popularity and name fell by the early 1990s. IBM tried to revive it through an intense marketing campaign as it tried to outdo Ethernet in terms of performance and reliability, but was unable to match its adequately priced competition. Today, IBM no longer supports, promotes, or uses the Token Ring.

Brief History
When it was tested in 1985 by IBM, the Token Ring transmitted data at 4 Mbit/s and eventually reached the 16 Mbit/s benchmark in 1989 with the 802.5 standard being extended to support it. Apollo Computer outdid IBM in 1981 when they introduced their Apollo Token Ring (ATR), by transmitting at a 12 Mbit/s speed and along with Proteon who introduced their ProNet-10 Token Ring in 1984 which reached 10 Mbit/s. Ironically though, IBM's was not compatible with neither of the two's Token Rings.

Inside the Technology
As anyone might be able to guess, as the name suggest, the Token Ring LAN is when stations are ordered in a ring topology. In this ring, stations will transmit data from one ring station to another with a control token in the middle circulating. To pictorially put, a Token Ring network is like a star, with loops going in and out from the middle of the station to the hubs at the outside. It is cabled with the IBM "Type-1" shielded twisted pair. However, these hermaphroditic connectors were not the most ideal cables, as they were quite huge, requiring a 3 x 3 cm space, and made up of complex and fragile plastic pieces.

A Token Ring is basically a local area network protocol within the data link layer (DLL) of the OSI model. As its name suggests, it uses what is called a token, a three-byte frame, which revolves around a ring in a loop. Since each station repeats this procedure of using the token and the ring, and to its downstream neighbor, this is how access is established among the stations. A station would acquire the necessary token and then transmit it.

Later, 4 Mbit/s and 16 Mbit/s speeds were standardized by the IEEE 802.5 working group. As technology developed, 100 Mbit/s was standardized and eventually, 1000 Mbit/s speed too in 2001, although none were bought in the market.

Although the Token Ring LAN was deemed superior to the Ethernet at the beginning, tests showed otherwise. With the introduction of switched and faster versions of the Ethernet, the Token Ring began to show lags and eventually fell behind in performance and reliability too.

Inserting the Token Ring
There is a five phrase ring insertion process before a station can be a part of the ring network. If one of the steps are not done properly, there could be an error.
 Lobe Check (Phrase 0): The station that is to be placed in the network will first perform a lobe media check. It is wrapped at the MSAU and then send and receive 2000 test frames to see that there is no error during these transmissions.
 Physical Insertion (Phrase 1): A 5 volt signal will be sent by the station to the MSAU. This opens up the relay.
 Address Verification (Phrase 2): Then, the station will transmit MAC frames to the destination address field of the Token Ring frame using its own MAC address. If everything is normal (frame is returned with the address is copied), the station is to participate every seven seconds in a ring poll process. This process is the time when the station fully identifies itself as a portion of the MAC management functions.
 Participating in ring poll (Phase 3): Now, the station will learn its Nearest Active Upstream Neighbor (NAUN). Then, its other downstream neighbors will know of its address, which also completes the creation of a new ring map.
 Requesting Initialization (Phrase 4): Last but not least, the station will send out a request to the parameter server to be correctly configured for the ring. This is done through a special address known as the Token Ring bridge.

Article Source: http://www.articlesnatch.com

About the Author:
James Smith writes on topics such as Token Ring , Asynchronous Transfer Mode and Lan Switches for The Tech FAQ.

Tags: communications, network, nodes

Print |

Ezine Ready |

Please Rate this Article

Recent Communications Articles

How Seperation Can Save a Marriage By: philo - Sometimes, married life may become extremely stressful and the couple may find it miserable to live together. When this happens, some couples wish to have a trial separation which may help to work through the difference between both the partners. In some cases, separation is prohibited by cultural or religious rules and they prefer to live apart though legally remaining married. The question is that can separation save a marriage and does it really work? There two ways of marriage separation, either informal separation or legal separation.
Tags: communications, marriage problems, marriage 101discount home gym, home gym informationmarriage counselingbest gas mileage cars
Free Internet Calls: A Thought Discussed on a Phone For Free By: Nisha Garg - The Red Indians sent smoke signals to communicate among themselves and the soldiers used Morse code during the WWI. However, the golden day when a wonderful person and a marvellous inventor called Alexander Graham Bell invented the telephone, bought with it not only a sunny morning but a new way to communicate. Since then telephone lines have been an integral part of the human life and has created an identity of its own.
Tags: communications, free internet calls, internet calls, make free internet calls
Why Buy A Wireless Bluetooth Headset By: Lee MacRae - Bluetooth devices are becoming more and more popular around the world with millions of people buying them every year. One of the most popular is the bluetooth wireless headsett. For those not acquainted with this Bluetooth device, follow along as this article will discuss what a Bluetooth headset is and why so many are snapping them up around the world.
Tags: communications, bluetooth headset, bluetooth headsets, wireless bluetooth headset, wireless bluetooth headsets
Reverse Cellular Phone Directories - Know Your Caller By: Davion W - Reverse cellular phone directories have been gaining a lot of popularity, for the reason that reverse cellular phone directories make it possible something that has been deemed impossible before --- that is, to trace the owners of cell phone numbers. Using this truly advanced method, you can immediately spot who your detractor is, and perhaps, initiate some steps in order to stop him from disturbing you.
Tags: communications, reverse cellular phone directories, phone number, address, background search
Telecoms in Pakistan By: Caroline Telford - One of the best ways to measure the growth of a particular country is by the sophistication of the facilities offered by the major telecoms. In an ever-changing industry in terms of technology, it is a must to keep up with the latest that technology has to offer - and this is best done with the help of telecoms. Telecommunications: A Definition & Its Numerous Advantages It is quite difficult to imagine a world without the telecommunications medium that we are using today.
Tags: communications, pakistan, telecoms, cheap calls, international calls
Telecoms in the USA By: Caroline Telford - If you live in a country which has the strongest economy in the world, you would naturally expect it to come with benefits. Probably one of the perks that Americans enjoy is the fact that when it comes to the telecommunications facilities available in the USA - almost all of the major telecoms have state-of-the-art facilities. This means that sending e-mail messages, making cheap calls, international calls, sending fax messages - almost any form of modern communication is possible.
Tags: communications, usa, america, telecoms, cheap calls
Telecoms in Brazil By: Caroline Telford - Wireless, landline, mobile, cable, satellite, Internet and Voice Over Internet Protocol or VoIP. These are just some of the types of services offered by telecom providers. No matter which part of the world it is that you are in, the modernity of the telecommunication facilities offered by the major telecom providers in your area will have an impact with the way that you communicate with the rest of the world.
Tags: communications, brazil, telecoms, cheap calls, international calls
Telecoms in Spain By: Caroline Telford - The impact of not having the means to use modern telecommunication facilities can be illustrated in a few examples. First, if a business owner has two stores which are in separate locations. Without a means for instant communication - the business owner would need to travel from one store to another in order to coordinate the daily aspects of running a business. Not only will this consume a lot of time, but it is also not cost-effective.
Tags: communications, spain, telecoms, cheap calls, international calls
Telecoms in China By: Caroline Telford - China is not just the world's most populous country, it is also the third largest country by area. With over a billion people residing in the China, how do you think the country will fare economically and socially if it does not have modern telecommunications facilities? Telecom: The Basics Before delving deeper into the details of China's telecom industry, let us first take a look at some of the industry basics.
Tags: communications, china, telecoms, cheap calls, international calls
Telecoms in Germany By: Caroline Telford - For today's younger generation, it is quite difficult to imagine a world without e-mail messages, fax, mobile phone calls, text messaging and even video calling. As technology becomes more and more advanced, the means of communication that we are using make it possible for us to send instantaneous messages back and forth. The Role and Importance of Telecom Providers in Society Before revealing the importance of telecom providers in society, here is a brief definition of the term.
Tags: communications, germany, telecoms, cheap calls, international calls

Comments

Search Ebay

Still can't find what you are looking for? Search for it!

ArticleSnatch Authors:

Member Login Sign Up Submit Articles FAQ Submission Guidelines Top Authors

For Publishers:

For Everyone:

Blog About Us Link to Us Contact Us New Stuff Link Directory Privacy Policy Sitemap Resources

Our Sites:

Free Magazines Book Your Hotel Stay Free MySpace Tools Massive Video Collection

Stay and Watch a Video:

Click here to submit your free, permanent ads to TheFreeAdForum.com!

Submit Your link to the Open Link Directory Project

Copyright 2005-2008 MJE Sales, LLC. All Rights Reserved.
Proud member of the ArticleCkr Search Network Search Network!
ArticleSnatch.com is free for both publishers and authors to use and is supported entirely from advertising revenue.
Use of our service is protected by our Privacy Policy and Terms of Service.