Subject: RE: Appletalk routing.... please help!!!

From: [email-masked]
Date: Tue, 9 May 2000 09:52:57 +0100

No if you have any redundant links that are routing AppleTalk this causes
problems. Had this problem with our WAN.  One solution would be to only use
AppleTalkIP or if either the Macintosh or Server you are using dosn't
support this Tunnel AppleTalk inside IP.

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From: "Tom Watson" <[email-masked]>
Date: Wed, 10 May 2000 00:28:20 -0800

On Tue, 9 May 2000 11:54:23 -0400 (EDT), [email-masked] wrote:
> At 23:21 Uhr -0400 08.05.2000, Konstantin Reznitsky wrote:
> 
> >Can appletalk handle multiple routes, what sometimes is called multipath?
> >Is there such a thing in the appletalk world? From what I know about
> >RTMP - it is RIP based, so here might be a problem.
> 
> From what I *think* (this means I'm not certain) Apple tried to make
> AppleTalk as foolproof as possible. So I think it can handle multipathing.
> 

When I did some testing of AppleTalk for A/UX (about 10 years ago), we
had a setup in a lab with a bunch of MacII's as routers.  Some of them
had multiple routes from one side of the rack to the other.  If I
remember correctly (I have no notes at hand), the route taken varied
from time to time.  In particular, the routing did NOT take into
consideration the speed of the link.  Some of the "dual" links had
both EtherTalk and LocalTalk wires from machine to machine.  The router
didn't care which one it took.  Everything worked as advertised, and
the packets made it form the source to destination.  I do not recall
if the route alternated, but I vaguely remember that it might have done
that.  It definitely was NOT an "Open Shortest Path First (OSPF)" net.

I do know that if a link went down, it took a while to get the packet
across the net.  The bad link needed to be killed, and if the router
before knows about it, it will broadcast back.

Most AppleTalk routers are built/designed by non-Apple third parties,
and might have "modified" routing methods.  For the most part they
follow the descriptions given in _Inside AppleTalk_ (the second
edition better describes routing for Phase 2 AppleTalk networks.

Phase 2 of AppleTalk was needed because on large networks (like the
one Apple has) the routine tables were being exchanged at the rate
of about 100/minute (per second??) on an IDLE network (like 2 AM).

The general configuration of an AppleTalk network is VERY VERY robust.
If you plug it together, it will most likely work.  The simplest being
an ImageWriter cable.  It works like a 10Base-T crossover cable.

Hope this information is of use.
-- 
Tom Watson         Generic short signature
[email-masked]     (I'm at home now)

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From: [email-masked]
Date: Wed, 10 May 2000 14:08:14 +0100

I have experienced problems with WAN/LAN's with AppleTalk DDP loops in them.
Maybe the following URL will explain the why if you are using Spanning Tree

http://til.info.apple.com/techinfo.nsf/artnum/n30922