Re: Ethernet carrier sense during transmit


John Leong (leong@andrew.cmu.edu)
Thu, 2 Oct 86 18:30:49 edt


Re :

"..... Ethernet assumes a certain maximum transceiver cable length and a
certain minimum signal propagation velocity .... The Codenoll system alters
the parameters which permit the monitoring of carrier. As such, calling it
"Ethernet" or "Ethernet compatible" could be misleading and could cause
network failures which are hard to diagnose such as your case. ...... "

I am curious as to how the Remote LANBridge function in conjunction with the
DEC remote repeater. Does the AMD chip inside the LANbridge, pointing to the
direction of the long fibre link, programmed to carry out the
CarrierSenseTest ?

Furthermore, it is my contention that doing a CarrierSenseTest is probably a
good thing but the timing is questionable bearing in mind that the 50 meter
transciever cable distance is really a function of DC power attenuation
between the controller an the transceiver. If the tranceiver is locally
powered, that distance limitation would not have applied. The only relevant
number will then be the 51.2 microseconds (512 bits) slot time.



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