mangler@cit-vax.UUCP (01/19/87)
Our Sun 2/170 fileserver has a Sun Ethernet board (Intel chip)
which receives efficiently, but has high software overhead on
transmitting. We also have some 3com Multibus Ethernet boards
lying about, which have much lower transmit overhead, but not
enough receive buffering. I'd like to pair up the two boards,
with the Sun board doing all the receiving and the 3com doing
all the transmitting, to get the best of both.
Arranging to have the 3com board do all the transmitting is
easy - I can do that with routing table entries. But Sun Unix
assigns the same Ethernet address to both boards, so unless
I suppress reception, all packets will be received by both
boards. How does one go about suppressing reception on the
3com board? I assume I can't just disconnect the receive
wire pair, because the transmitter needs to know when another
carrier is already present, right? Perhaps there's some other
way to disable receiving, or at least the receive interrupt?
No, of course I don't have driver source, and my prospects for
getting it any time this decade look slim. A hardware solution
would be preferable anyway (hardware patches don't have to be
reapplied on every release). A jumper to remove? A trace to cut?
Is this an even vaguely reasonable thing to be trying? Too bad
Sun didn't make their fancy board efficient at transmitting...
Don Speck speck@vlsi.caltech.edu {seismo,rutgers,ames}!cit-vax!speck