Newsgroups: can.uucp
Path: utzoo!utgpu!jarvis.csri.toronto.edu!neat.ai.toronto.edu!rayan
From: rayan@AI.TORONTO.EDU (Rayan Zachariassen)
Subject: Re: .CA root servers
Message-ID: <89Apr13.220817edt.38140@neat.ai.toronto.edu>
Organization: Department of Computer Science, University of Toronto
Distribution: can
Date: Thu, 13 Apr 89 22:08:07 EDT

In article <520@aurora.AthabascaU.CA> lyndon@aurora.AthabascaU.CA (Lyndon Nerenberg) writes:
# Who (if anyone) is acting as the root server for .CA ?

relay.ubc.ca is the primary,
clouso.crim.ca, nnsc.nsf.net, and bay.csri.utoronto.ca are presently
the secondary authoritative servers.

# It appears that noone advertises an MX for .CA; I thought that all top
# level domains connected to the Internet required this.

Right.  Nope.  See below.

# I was also a bit surprised to discover there is no "meta gateway" for
# .CA listed in the maps. These do exist for .edu, .com, etc., why not
# one for .CA ?

Actually, there were a few listed, namely the U.S. UUCP->Internet gateways.
I (re-)discovered this a few days ago and asked for them to be removed.
They serve no purpose because *all* .CA domains are listed with explicit
routes in the pathalias data, so if it isn't in the map it doesn't exist.
Hence there is no point sending it to a gateway like (e.g.) uunet, because
they won't know any better than you do.

What you are expecting is commonly called "topological routing".  You
have to remember that the namespace is completely orthogonal to the
routing problem; think of domain names as uucp node names and you will
have a good idea of how names relate to routing (they don't).  Usually
topological routing is used at the point where the namespace hierarchy
closely resembles/overlaps the network topology, e.g. at organizational
gateways.  If one did this at the country level without a corresponding
network topology, you would put unwarranted strain on one or a few gateways
instead of distributing the traffic.  Ideally there should be NO change
in traffic pattern just because a site converts to using domain names.

# (I ask this because domains were supposed to solve a lot of problems
#  w.r.t mail routing. After convincing a number of local users to use
#  domain addresses they are beginning to think the whole concept quite
#  rude when domain addr's return "no such host" but old fashioned bang
#  paths still work.)

I can't think of any reason for it to not work unless if the subdomain in
question doesn't properly support their own name.  If there is a problem
with the maps or the forwarding mechanisms on the various nets, let me
know the details and we can investigate.

The reason that domains were supposed to solve a lot of problems were
primarily:

- they specify absolute addresses, no more source routes or bang paths
  unless you or your mailer have good reason.
- the organization-internal routing can be hidden from the outside world,
  which means one only needs routing information for the *sub*domain as
  a whole (in terms of its gateways) rather than all internal hosts.

Wildcard routes to .CA are indeed used to reach NetNorth and CDNnet's gateways
to the outside world, but that is because they both operate a single gateway
to the world so all traffic has to go through it anyway.  The Canadian
UUCP network probably has 20 links to the U.S., so topological routing
is not reasonable, nor is it necessary since any gateways would have no
better routing knowledge than any other site using the UUCP maps.

rayan