A switch recieves data in it's port buffer at 100 mbps, as the frame travels
the switches backplane it is copied to all ports, when it arrives at an ASIC
chip (I forget if it's the Earl or what)in the SUP module, the module looks
in it's table and decides what port it should go out of and tells all other
ports but that one to flush their buffers and the forwarding port to
forward. So you see the frame arrives at the port at 100, but travels the
backplane at a constant speed as it is traveling the backplane it is copied
to the 10 meg port (all ports actually), after the asic decides who flushes
and who forwards, the forwarding port tells the 10 meg port to forward.
This is my understanding of what happens. Corrections and additions
welcome!!
-----Original Message-----
From: Rick Holden [mailto:[EMAIL PROTECTED]]
Sent: Thursday, January 11, 2001 8:34 PM
To: [EMAIL PROTECTED]
Subject: switch flow control
There is one thing that confuses me about switches. If you have a switch
with a 100Mb port and 10Mb port and the 100 starts sending data to the 10
how does the sending station keep from overflowing the buffer on the switch
since there in now flow control at layer 2?
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