[31619] in North American Network Operators' Group
Re: Statistical Games Providers Play (RE: availability and
daemon@ATHENA.MIT.EDU (Vijay Gill)
Sun Oct 1 00:54:25 2000
Date: Sun, 1 Oct 2000 00:52:38 -0400
From: Vijay Gill <vijay@umbc.edu>
To: Sean Donelan <sean@donelan.com>
Cc: nanog@merit.edu
In-Reply-To: <20001001042059.19747.cpmta@c004.sfo.cp.net>
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On 30 Sep 2000, Sean Donelan wrote:
> If you look at network backbones, almost everyone uses the same
> vendors, supplying essentially the same equipment, and nearly the same
> network design. So why would different providers have different
> availability numbers? Is it just an accident of the statistical
> series, some providers had their failures earlier but everyone will
> end up the same in Year Infinity? Or are there real differences,
> besides price, between providers?
There appear to be two major and some minor variants in backbone
engineering and architecture. The major ones being the UUNET design and
the Sprint/Qwest design for circuit layout and aggregation/hierarchy.
There are a lot more variants regarding the routing architecture (IGP
setup, bgp setup, et al), and depending on various failure modes, some are
better than others for a subset of failures and vice versa.
The hierarchical UUNET design for example, is fairly dense in terms of
volume, with a small time diameter per region for a network of that size,
which allows for some local optimizations. And if you get two circuits
into two regions, some failures in one region can be isolated and
compartmentalized, without a major spillover into the neighboring regions,
which would not be the case in a large flat network.
As always, with good engineering, comparable reliability can be
established, given appropriate amounts of money being thrown at the
problem.
/vijay
