ethernet interface perversity


I am only an egg. (JOHNSON%nuhub.acs.northeastern.edu@RELAY.CS.NET)
Tue, 4 Aug 87 17:03 EDT


     Hold it a minute. I have received many responses from my query
about network numbers on an ethernet. Thank you for all the positive
help for those who gave it but . . .

     I NEVER intended to complain or panic about IP. I was in search of
verification of something and perhaps I phrased it poorly. And yes I
know that one ethernet wire can have large numbers of internet addresses
floating around on it.

     We did some experimentation with our various ethernet interfaces
and discovered that something which was hinted at in many of the
responses seems to be true. The ethernet interfaces we have will each
respond to only one internet number at a time. I talked to Micom for
example and they even said as much for their np100 board.

*FLAME ON*

     It seems very dumb that I need at least one gateway node on one
ethernet wire so that nodes on that wire can all talk to each other when
some of the nodes run with different internet numbers.

     Although my problem is really an administrative one (I don't run
the whole network here, I just get dumped on when it doesn't work), I
don't see why I should be having a problem at all. I read ARP, rfc 826,
and it talks about an address translation table. Note the use of the
word TABLE. In this age of micro-processors it seems more than feasible to
put some real table driven ARP intelligence out there so that interface
boards can RESPOND TO MORE THAN ONE BLOODY ADDRESS.

     I suppose someone is going to ask how big the table should be. I
don't know. Memory is cheap. It could easily be big enough to handle
16 or 32 network numbers. It could even be content addressable and thus
FAST. Allowing for 16 or 32 network numbers (or more) should reduce the
frequency of ether_type$ADDRESS_RESOLUTION packets to small for most
cases.

*FLAME OFF*

     I'm just upset with the vendors for giving me ulcers again. So
what else is new :-(.

USnail:
          Chris Johnson
          Academic Computer Services
          Northeastern University 39RI
          360 Huntington Ave.
          Boston, MA. U.S.A. 02115
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CSNET: johnson@nuhub.acs.northeastern.edu
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(Always vote. There may not be anything you want to vote for, but
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