Differences between version 7 and predecessor to the previous major change of CSMA/CA.
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| Newer page: | version 7 | Last edited on Tuesday, March 9, 2004 6:09:27 pm | by SamuelFalvo | Revert |
| Older page: | version 6 | Last edited on Wednesday, October 15, 2003 4:40:16 pm | by CraigBox | Revert |
@@ -6,4 +6,10 @@
__NOTE__: Although the above description may be true, the more commonly accepted description of [CSMA/CA] is attached to TokenRing networks. Token ring achieves collision avoidance by only allowing a computer which is currently in possession of the token to transmit. In such a configuration, there is never the possiblity of a collision. This explains why in many cases 16MBit token ring ([CSMA/CA]) can easily outperform 100MBit [Ethernet] ([CSMA/CD]).
Also, contrary to popular misconception, it is possible (and common) to use more than one token on the network. The data traversing the network still avoids collisions by only allowing transfer of data in one direction around the ring. While this may sound inefficient, it is in practice quite an impressive performer.
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+What is your source for the above information? Clearly it depends on network load factor. 100MBps Ethernet can transfer data at a blistering rate compared to 16MBps TokenRing, and with substantially less latency to boot. Coupled with a multi-port ''switch'' (and not a hub), total network aggregate bandwidth can achieve many times this rate, perhaps even going into the gigabits per second, for switches with suitably numerous ports.
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+Also, TokenRing is __not__ CSMA/CA. There is no carrier sensing at all -- if you don't have the token, you have no need to sense a carrier, because you cannot transmit (legally) on the network at all. TokenRing is a variation of DAMA (DemandAssignedMultipleAccess), which can also be applied to bus-topologies as well as star-topologies (e.g., DAMA has proven itself quite well in an amateur packet radio environment, even despite the 1200bps and 9600bps link rates).
