Poor X-core performance


Ron Natalie (ron@BRL.ARPA)
Thu, 20 Mar 86 2:24:42 EST


I was doing some tests regarding the execrable (what a word!) cross-core
performance and have made the following observations:

        1. Going between two MILNET hosts or between two ARPANET
                hosts seems fairly quick.
        2. Pinging the gateways seems to be fairly quick.
        3. Going from a net gatewayed to MILNET to the ARPANET side
                is slow.
        4. Going from a host on the MILNET to the ARPANET side is slow,
                but a little faster than 3.

Now, I know a limitation of GGP forces packets from my host to go:

    BRL-HOST -> BRL-GATEWAY -> MILNET-GW -> ARPA-EGP-SPEAKER ->
         ARPA-USER-GW -> ARPA-USER -> MILNET-GW -> MILNET-EGP-SPEAKER ->
                BRL-GATEWAY -> BRL-HOST

Now the IMPs control traffic between host pairs by the RFNM/blocking
procedure. The BRL-GATEWAY->MILNET-GW doesn't seem to be much of a bottle
neck (though BRL-GATEWAY did seem to rank 11th in MILNET host packet counts).
However, it seems that a lot of net traffic in addition to BRLs gets piled
into the MILNET-GW -> ARPA-EGP-SPEAKER and MILNET-GW -> MILNET-EGP-SPEAKER
paths which probably is presenting the bottleneck. I'll be able to test
this further later this week when I fix our system to allow me to set up
arbitrary IP options (anyone want to set up an ECHO host on the ARPANET?
ISI-ECHO doesn't, IPTO-ECHO seems to be there though).

-Ron



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