Home page logo

nanog logo nanog mailing list archives

Re: Which RFC?
From: Susan Roycroft <susanr () cisco com>
Date: Thu, 02 Jan 1997 12:10:36 -0500

also, 1058, rip RFC 'Entities that use RIP are assumed to use the most
specific information available when routing a datagram.'


Bill Woodcock wrote:

        > Anyone know *which* RFC says a packets should be routed using
        > the most specific route in a routing table, not (for instance)
        > the first route in the table that matches, or, for instance,
        > using a less specific route that has a better metric?

    It might be worth your while to look through the sections of RFC 791
    and subsequent revisions which define the second byte of the IP
    header, which sets the delivery-priority and the class-of-service for
    the packet.  The class-of-service (type-of-service?) field lets you
    specify whether you want the shortest, largest, cheapest, or most
    reliable route, those being mutually exclusive.  In my experience,
    both fields are set to 0 on just about all packets, which doesn't
    specify any requested class-of-service.  That presumably leaves the
    router free to choose any route it likes, at its discretion.

        > This is so basic I hardly know where to find it

    If the router, in its discretion, chooses to route the packet in the
    wrong direction, that should be easily demonstrated and reasonably
    incontrovertable, no? What's your vendor's argument in favor of
    shipping the packet to a nearby site which isn't associated with your
    destination?  I'm kind of curious to hear it...

    Who's the vendor?  Please humiliate them publicly.  :-)


bill woodcock woody () zocalo net woody () nowhere loopback edu user () host domain com

Susan Roycroft (formerly Susan Holdridge)
cisco Systems, Inc.
Customer Engineering
ccie# 2322
- - - - - - - - - - - - - - - - -

  By Date           By Thread  

Current thread:
[ Nmap | Sec Tools | Mailing Lists | Site News | About/Contact | Advertising | Privacy ]