• United States

Token ring and Ethernet differences

Jan 27, 20032 mins

Nutter explains the differences between token ring and Ethernet networks

We are planning to install a new network for boiler automation. There are two way the vendor has told us we can do go, to use Ethernet (100M bit/sec) or token (10M bit/sec). Could you explain about these networks and your recommendation?

– Via the Internet

I think your vendor probably meant 16M bit/sec token ring. Token ring was primarily used in networks where there was a high level of traffic anticipated on the network. The downside to token ring was that it was typically more expensive to install. Not so much in terms of the wiring but the hubs, or MAUs, as they are called. Early implementations used the IBM Type 1 cabling system, which used a large square connector at the end of the cable.  Later iterations were able to go with the RJ-45 connector also used for Ethernet.

100M bit/sec Ethernet will be several times faster than the 16M bit/sec token ring as a general rule. The cost of Ethernet hardware is far cheaper than token ring ever was with $15 network cards and $40 hubs. Depending on what wiring already exists in your facility, you may be able to use something you already have or add additional workstations to network for minimal cost when your needs grow.

An important distinction between the two topologies is that token ring is a token-passing system in which only one workstation can talk at a time. It has to be in posession of the token in the packet; no one else is supposed to be able to talk until their turn comes.  Ethernet is a Collission Sense Multiple Access/Collission Detection (CSMA/CD) topology.  This means that if multiple workstations start talking at the same time, they will all shut down, wait a randomized period of time and then start up.  What is theoretically supposed to happen is that one workstation will start talking before the others do, and the remaining worsktations will see that someone is talking and remain silent until the current talking workstation has finished. If the vendor of the system you are looking at supports full-duplex Ethernet, you can be looking at a theoretical speed of 200M bit/sec.