The T1 Backbone will be shut down on Wednesday, December 2. Following is a list of events and changes that are taking place this week. Please let us know as soon as possible if you see problems with this plan or notice problems with backbone routing or reliability. 1) Most regionals/midlevel peers are already peering with both T1 and T3 backbones. Those using default routing are pointing default at T3. 2) ANS has installed backup T1 circuits to nearly all of the T3 ENSS nodes on the backbone. These are homed to a different POP than the T3 circuit, and as much physical diversity as was available was used to install the backup circuits. The T1 circuits will be used in the event of a DS3 circuit or CNSS failure, and these circuits are configured with a higher metric than the T3 circuit. 3) OSI CLNP encapsulation using the EON software in the T1 backbone RT nodes is currently partially enabled. That is, encapsulation is taking place for many sites in one direction but not the other. This configuration will be completed by Tuesday morning, December 1. At that point, encapsulated CLNP packets will be carried over the T1 backbone (ie. encap/decap at entry and exit PSPs). 4) On Wednesday morning the ethernet-PSPs at each NSS will be reconfigured to stop running psp_routed, start running gated, and default routes or IP destinations. That is, this PSP will be an OSI encapsulator only, with default IP routing pointing to the ENSS. If backup IP paths are available, it should be possible to configure the RT to have multiple default routes. 5) EASInet is currently linked to NSS-10 at Ithaca. The T1 circuit is being rerouted to the ANS New York POP to allow an RS/6000 ENSS to be used, but it is not certain that this circuit will be up by Wednesday morning. If not, NSS-10 will still be partially enabled to allow it to act as a router between EASInet and the T3 ANS Backbone. 6) CA*Net is currently linked to the NSS's at Seattle, Princeton and Ithaca. Merit and CA*Net are working on reconfiguring the RT nodes at the US ends to run the CA*Net software and run as part of the CA*net routing domain. However, since this is not ready yet, the three NSS's will be used as a router between CA*Net and the T3 ANS backbone with a minimum of hardware and software changes. This will take place on Wednesday morning. 7) In advance of Wednesday there will be a special configuration run for the T3 backbone to allow the final configuration of all backup AS paths for all networks to be installed. Some of the backup AS paths were not added during cutovers of traffic since at the time the backup AS's had not been cut over. This will be covered in a separate announcement sent to the nwg@merit.edu list. 8) AS 68, Los Alamos National Laboratory networks have been cut over to the T3 Backbone. AS 22, operated by Milnet at San Diego Supercomputer Center, will be cut over on Tuesday morning. These are the final holdouts on the T1 backbone, except for CA*Net and EASInet. 9) Please do not stop your peering sessions with the T1 backbone in advance of the December 2 shutoff date. There may be problems with CA*Net and EASInet routing if this is done without coordination. More details about exact times for these activities will be sent in additional messages. Please feel free to contact me if there are problems with this plan, or mail ie@merit.edu. --Mark Knopper Merit/NSFNET Internet Engineering