[1812] in Commercialization & Privatization of the Internet
Fair Competition
daemon@ATHENA.MIT.EDU (Jordan Becker)
Tue Dec 31 16:40:02 1991
Date: Tue, 31 Dec 91 16:35:56 EST
From: Jordan Becker <becker@ans.net>
To: com-priv@psi.com
>
> <<MESSAGE from>> Gordon Cook 28-DEC-91 21:57
> cook@tmn
> One thing i note about the T-3 core node backbone is that each node has
> but two paths. And I believe that each end node has but one path into and
> out of the MCI national backbone. Now I am new to networking so there may
> be something that I am missing here, but as I remember every node except
> one on the old t-1 backbone had THREE paths to the rest of the network,
> the one that did not had two paths (the midnet node I believe).
The current T3 topology map may be anonymously FTD'd from ftp.ans.net. There
are currently 6 out of 12 core backbone nodes that maintain 3 redundant T3
links to other core nodes. The other 6 core nodes maintain 2 redundant T3
paths to other core nodes. This does not include the T1 safety net links
which provide added redundancy in the event that all T3 links from a core node
become unreachable. There are 3 points of interconnection between the T1 and
T3 networks including Ann Arbor, San Diego, and Houston, although right now
only one interconnect is active at a time.
> Would it be correct to conclude that such a network topology is MUCH more
> failure prone than the T-1 net that is about to be turned off.
No this would be an incorrect general conclusion. The T3 network has actually
been quite reliable since early November, and there are no immediate plans to
turn the T1 network off. We will be working to cutover additional traffic
from T1 to T3 during the coming weeks to offload some of the congestion on T1.
Jordan
