Proposed change at the Interconnect
skw
skw
Tue Nov 10 09:16:37 UTC 1992
All,
This change will take place with today's update.
--Steve Widmayer
Merit/NSFNET
***********************************************************************
>Date: Mon, 2 Nov 92 17:26:04 EST
>From: epg at merit.edu
>To: regional-techs at merit.edu
>Subject: Proposed change at the Interconnect
>Cc: epg at merit.edu
>
>The T1 backbone and the T3 backbone have provided a backup path to
>mid-level networks which peered with both backbones.
>
> x
> / \
> / \
> +------+ +------+
> | | | |
> | T1 |------| T3 |
> | | | |
> +------+ +------+
> / \ / \
> / \ / \
> a \ / \
> \ y / b
>
>This was done by announcing all known networks from one backbone
>to the other via the interconnection between the two. One of the
>benefits of doing this was that it provided a transition from the
>T1 backbone to the deployment of the T3 backbone.
>
>Now that almost all of the peers that were known to the T1 are
>also known directly to the T3 and the T3 has implemented
>backup plans in addition to the T1 backbone, we would like to
>stop announcing the networks associated with dual homed peers
>from the T3 to the T1. This means that T1 only networks will
>no longer have a backup path through the T3 if a dual homed site
>loses its connectivity to the T1 backbone.
>
>In this proposed configuration, at the interconnection, the
>T1 will announce networks a, x and y to the T3. At the interconnection,
>the T3 will announce network b to the T1. This plan will have the
>following affect:
>
>1) if the connection between x and the T1 breaks,
>
>b will reach x via the T3
>y will reach x via the T3
>a will find x unreachable
>
>or
>
>2) if the connection between x and the T3 breaks,
>
>b will reach x via the interconnect to the T1
>y will reach x via the interconnect with the return path via the T1
>a will reach x via the T1
>
>CA*net and EASInet are the only peers which remain T1 only. We have
>contacted them previously concerning this proposal and they are
>aware of the proposed change. We are also in the process of working with
>those two organizations to convert them to the T3 backbone.
>
>We would like to make this configuration change by the end of this
>week, November 6, 1992. This step will help to maintain the T1
>backbone until the remaining peers have transitioned to the T3
>by reducing the amount of routing information that the RTs need
>to assimilate. It is also another step in preparation to
>the eventual dismantlement of the T1 backbone.
>
>If you have any questions concerning this proposal
>please notify us as soon as possible.
>
>Thank you.
> --Elise
>
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