Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!pasteur!ucbvax!MITVMA.MIT.EDU!KASTEN
From: KASTEN@MITVMA.MIT.EDU (Frank Kastenholz)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Dumb vs. smart host routing
Message-ID: <8805192145.AA23123@ucbvax.Berkeley.EDU>
Date: 17 May 88 13:39:39 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 32

>From: Mike Brescia <brescia@PARK-STREET.BBN.COM>
>
>    <from kasten@mitvma.mit.edu>
>     a certain well known computer company has made a network package for PC's
>     and PS/2's that does not understand ICMP redirect.
>
>This is an interesting turn.  What if they try to send to a gateway that does
>not forward packets which needed redirect.
> a. host sends to gw A
> b. gw A redirects host to gw B
> c. gw A now has no more buffers, drops pkt
> d. host ignores redirect
> e. go to a

>The IP spec does imply some effort be made to forward a redirected packet, but
>I interpret the priority to be higher to get the redirect to the host, and
>only secondary that the packet be forwarded.

If this occurs then I imagine that the host will remain mute for all
eternity. I was not able to try anything like this though - we are
just going to tell our customers that "Here is a failure mode that we
(ATEX) can not fix - so if it occurs, ......."

We have aother PC based (using the P.D. MIT PC/IP code) product that
will have "multiple default" gateways, as was discussed on the list
earlier. The transport/application layer will ask IP to try another route
in the event of excessive transmission errors (i.e. no receipt of an ACK)

Cheers
Frank Kastenholz
Atex/EPPS - a Kodak Company
All opinions are mine and in no way belong to Atex/EPPS/Kodak (in fact
they don't even know that I am saying this)