Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!nrl-cmf!ames!pasteur!ucbvax!HOGG.CC.UOREGON.EDU!jqj From: jqj@HOGG.CC.UOREGON.EDU Newsgroups: comp.protocols.tcp-ip Subject: Re: Subnetting Message-ID: <8805102321.AA26819@hogg.cc.uoregon.edu> Date: 10 May 88 23:21:11 GMT Sender: daemon@ucbvax.BERKELEY.EDU Organization: The Internet Lines: 26 > The Internet standard approach for a host: pick any >gateway and let it redirect you... is simple and effective. .... but works abysmally given the typical host software that allows you either to (1) set a static default route to the world, or (2) run passive RIP or something like it. If I choose option 1 and the default gateway crashes, it won't be around to send ICMP redirects telling me to use the backup gateway. Phrased differently, the "Internet standard" does not adequately address the issue of how a host should pick the first gateway to try. >You REALLY DON'T want hosts to know about routing. At issue here is a critical point: how smart is it desirable for hosts to be? Braden argues that they should be very dumb. I would argue that they can be dumb if they don't really need connectivity off their network, but should be a little bit smarter if possible. If you concede that, then the next step is to decide whether it is better for a host to have: (1) a static list (n>1) of gateways to try; (2) some as yet undefined dynamic discovery mechanism for a host on a network to find the list of gateways without getting routing data; (3) hosts that listen to routing traffic and hence could potentially use the data to avoid that first bad choice of a gateway. My personal bias: Passive RIP works just fine in the XNS world as a HOST protocol as well as as a gateway protocol. It works adequately in the IP world for typical CANs and moderately complex LANs. I see no real alternative available at present.