Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!gatech!purdue!decwrl!ucbvax!hogg.cc.uoregon.EDU!jqj From: jqj@hogg.cc.uoregon.EDU Newsgroups: comp.protocols.tcp-ip Subject: Re: Dumb vs. smart host routing Message-ID: <8805121656.AA28839@hogg.cc.uoregon.edu> Date: 12 May 88 16:56:52 GMT Sender: daemon@ucbvax.BERKELEY.EDU Organization: The Internet Lines: 30 John, I sympathize, and agree that yours is a defendable position. One problem with it is that it doesn't work if the local network is extremely dynamic, with lots of routers coming and going. An "ad absurdum" extension to your argument is that a host shouldn't have to have ARP; it should be able to make do with some static tables -- of course, that would be ridiculous since the list of hosts on the local network is much too dynamic to make such a table reasonable (though note that some implementations, e.g. SunOS 3.x diskless bootstrap, required just such a table). Similarly, I claim that we will need some sort of discovery mechanism if the list of gateways on a local network is expected to be large and dynamic. We have such a discovery mechanism in place today; passive RIP. I'm not recommending that we improve it, or that hosts use it for anything except finding the first gateway. Note that if in fact most host implementations already supported a list of default gateways then I'd be willing to live with that as an alternative. Unfortunately, they don't; most implementations give you exactly ONE default, which is not enough when that gateway crashes and stops sending ICMP redirects. >fixing this will be a bad enough problem without having to change all >the host software in the world I believe that a gateway can be taught to send out RIP packets saying "I'm a default router" without sending out any other data. If so, this would provide my desired discovery mechanism with no changes to a common flavor of host software (i.e. BSD derivatives).