I would much rather go in the other direction: to stop peering with the T1 backbone and to rely on the crossover for all T1 only traffic. This has several advantages: - The next transition (disconnecting the T1) is a NOOP as far as most sites are concerned. - Conversly there will be a flag day when the T1 is turned off - can you prove in advance that there will be no side effects? - We (the mid-levels) can move on to simpler routing configurations now - Merit can start to dismantle the fringes of the T1 backbone - Simpler diagnosis, because fall back to the T1 will not confuse pingers - Only a small subset of the T1 continues to be production critical to anyone. - With your plan, other possible changes become more difficult becuase sites can not stop peering w/ the T1. - It motivates all people who MUST have the T1 to move on. The NSF is spending a lot of money on T1 lines and electricity for NSSs which could be better spent elsewhere: I bet just a few months of bills will pay for the migration. Disadvantages: - It should wait until the all T1 safety tails are installed in the T3 backbone Ours is scheduled for later this week. - Lower performance to the remaing T1 only sites. - Sites using clnp..... Perhaps the decision can be made on a per site basis? How about just asking all regionals to drop their T1 announcements from 3 or 4 AS's to 1 or 2? Their choice... --MM--