From: trier@odin.ins.cwru.edu (Stephen C. Trier)
Newsgroups: comp.protocols.appletalk
Subject: Re: multiple phase2 zones on a network
Date: 7 Nov 1992 05:59:44 GMT
Organization: Case Western Reserve University, Cleveland, OH (USA)
Distribution: world
NNTP-Posting-Host: odin.ins.cwru.edu

In article <tdboyce-061192104131@lloyd-at1.caltech.edu> tdboyce@cco.caltech.edu (Tom Boyce) writes:
>Assume that all net devices agree on a range of 50 zone numers, say 1-50.
>Do all 50 zones have to be named at the time the net is configured?

Under phase 2, there is no relationship between zones and network numbers.
You can assign as many zones as you like to a phase 2 extended network
(one with a range of net numbers), and you can assign as many numbers as
you like.

The idea of the network number is for the computer's convenience -- it
has to know how to get packets from here to there.  The zones are strictly
for human convenience, to help humans name things and then find those
things when they need them again.

Here is how to figure out your configuration:  (When I say Ethernet below,
I really mean "Phase 2 Extended network".  When I say LocalTalk, I really
man "Phase 2 non-extended network".  I'm just being lazy...  ;-)

Network numbers

1. Figure out how big your Ethernet network number range(s) should be.
   To work this out, assume that each number in the range gives you
   up to 253 Macintoshes.  Make the range at least twice the number
   of Macs you plan to plug in, because they need room to pick their
   numbers, but don't go overboard, since wide ranges do reduce the
   efficiency of your AppleTalk routers.

2. Pick one network number for each LocalTalk cable.  LocalTalk cables
   cannot have a range of network numbers.

3. Make sure none of your network number ranges overlap and all of your
   LocalTalk network numbers are unique and do not lie within the network
   number ranges.

Zones

1. Divide your planned network into what are sometimes nicknamed "cables" --
   sections divided by routers.  Figure out what departments are on each
   cable.  (Note that, at least in our environment, a department may very
   well be on more than one.  That's OK.)

2. Make up a zone name for each department.

3. Pick one or more zone names for each Ethernet cable, including the zones
   for all departments on that cable.  Zone names can be used more than once,
   so pick where they go by where the people go.

4. Pick exactly one zone name for each LocalTalk cable.  These zone names do
   not have to be unique.  They can even be the same as zones appearing else-
   where on the Ethernets.

The final step is to tell the routers about the network numbers and zones
on the cables plugged into each of their interfaces.

Then all you have to do is to sit back and wait.  The exact assignment of
network addresses to computers is taken care of by the computers, with
some help from the routers.

The assignment of computers and printers to zones is taken care of by the
humans when they name the computers and printers.

As you can see, there's really no relationship between zones and network
numbers, so there's no need to assign them together.  The one is for routing,
and the other is for naming.  That's all there is to it.

Oh, one other note -- no matter what zones you put on the Ethernets, changing
them is a pain, and someone will inevitably want them changed.  :-)  I deal
with it by doing changes only once every three months, so I can at least batch
them up and add several zones at once.  (Changing the zone list around here
is a three-hour production, regardless of the number of zones added.)

-- 
Stephen Trier                                     
Network Services Engineering, IRIS/INS/Telecom    "Dessine-moi un mutton"
Case Western Reserve University                        - Le Prince
trier@ins.cwru.edu