Re: GS+Appletalk Phase 2

[mday@apple.com (Mark Day)]

In article <C12Kpz.4oK@utstat.toronto.edu>, philip@utstat.toronto.edu
(Philip McDunnough) wrote:
> 
> In article <m0nDuc5-0000xRC@crash.cts.com> kimba@gnh-cathouse.cts.com (Kim Brennan) writes:
> 
> [ ]
> >
> >That's a good question. I've another...what's Appletalk phase 2?
> 
> There's Phase 1 and Phase 2.0 , which is newer. These are versions of
> Appletalk (not the wiring!). As far as I can tell, Phase 2 allows more
> nodes in a network (Phase one had a 254 node limit). This primarily 
> affects Ethertalk (Appletalk running over Localtalk wiring). It's not
> supposed to affect Localtalk nodes, but I'm not sure about that (even though
> the manual claims that it doesn't).
>  
> Philip McDunnough
> philip@utstat.toronto.edu

AppleTalk Phase 2 is primarily intended for links that physically allow
more than 254 nodes per network (i.e., per cable).

AppleTalk addresses are comprised of a 16-bit network number and 8-bit node
number.  Node numbers of 0 and 255 are reserved, leaving only 254 node
numbers per network number.  With phase 1, you were restricted to a single
network number on any given network (i.e. cable).  Phase 2 removes that
restriction, allowing multiple network numbers on a single network, which
allows more than 254 nodes per network, and also more than one zone name
per network.  So, with phase 2, you could set up a network with several
hundred nodes, without needing a router.

Most of the changes for phase 2 only effect routers.  For non-router nodes,
there are a few changes to their startup process, in how they determine
their
address, zone name, and the address of a router.

None of the above changes effect LocalTalk nodes since LocalTalk is not an
extended network.

There were a few other changes introduced at the same time as phase 2,
notably
a way to select the timeout for ATP XO transactions (which was previously
hard-coded), and a new wildcard feature in NBP lookups.  These changes are
optional but encouraged for LocalTalk products; they have already been
incorporated into System 6 and will be in the Apple II Ethernet Card.

---
Mark Day, Apple Computer, Inc.
mday@apple.com