odd routings


Charles Hedrick (hedrick@topaz.rutgers.edu)
Sun, 28 Sep 86 04:48:39 edt


I have been looking at our EGP routings. I checked a few sites that I
know we talk to a lot. Our current EGP peers are yale-gw and
css-ring-gw. (We keep a list of possible peers, and the gateway picks
2. It will change if one of them becomes inaccessible. This particular
pair seems to be fairly stable.) Here I what I found:
  CMU: As far as I can see, the only way into CMU is cmu-gateway,
        10.2.0.14. The EGP table showed 10.3.0.27, which is
        gateway.isi.edu. We will hope that ISI would be smart enough
        to give us a redirect if we actually used this route, but
        it seems odd none the less. We tried to establish a direct
        EGP connection with cmu-gateway, but we were unable to
        acquire them. (In addition to the list of potential peers,
        our gateway also has a list of secondary gateways, all of
        which it will acquire. The intent is that these are gateways
        that are so important to us that we don't want to depend upon
        the core for information about them.) We have ended up
        adding a static routing to them.
  MIT: They seem to have 4 different networks. The ones with direct
        Arpanet gateways are 18 (using 10.0.0.77) and 128.52 (using
        10.3.0.6). EGP was telling us to use 10.3.0.27 (isi) and
        10.2.0.37 (purdue) respectively. Fortunately, we were able
        to acquire both of MIT's gateways, so I am simply going to
        list them as secondary gateways.
  Stanford: It appears that the only reasonable route to network 18
        is stanford-gateway, 10.1.0.11. Our EGP table was telling
        us to use 10.2.0.37 (purdue-cs-gateway). We were able to
        acquire the stanford gateway, and have also added them to
        our list of secondary gateways.
Am I doing something wrong? Here is the relevant portion of our
current configuration file. I confess that I do not know where the
list of primary neighbors came from. It seems to have been developed
by one of our systems staff after numerous dealings with the Network
Operations Center trying to diagnose problems. Note that the gateway
itself is Cisco Systems' commerical version of the Stanford Arpanet
gateway. It is based on a 68000, with an ACC 1822 card. This code
has probably not been used many places outside of Stanford, so it is
certainly possible that there are problems left with it. But it gives
every appearance of doing the right thing.

primary-neighbors 2
egp-neighbor 10.7.0.63 46 primary ! bbn-net2-gateway
egp-neighbor 10.2.0.37 46 primary ! purdue-cs-gw
egp-neighbor 10.0.0.94 46 primary ! wisc-gateway
egp-neighbor 10.3.0.27 46 primary ! isi-gateway
egp-neighbor 10.0.0.25 46 primary ! css-ring-gw (seismo)
egp-neighbor 10.0.0.9 46 primary ! harvard-gw
egp-neighbor 10.1.0.51 46 primary ! sri-prm-gw
egp-neighbor 10.1.0.54 46 primary ! cit-cs-gw
egp-neighbor 10.2.0.9 46 primary ! yale-gw
# talk directly to our friends, since these tend to have bogus routes
egp-neighbor 10.0.0.77 46 ! mit-gw, for net 18
egp-neighbor 10.3.0.6 46 ! mit-ai-gw, for net 128.52
egp-neighbor 10.1.0.11 46 ! stanford-gw, for net 36
# I can't get cmu-gateway to respond to EGP, so do it statically
route 128.2.254.36 10.2.0.14 ! cmu-gateway, for net 128.2



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