From: "Milo S. Medin" (NASA ARC NSI Office) <medin@nsipo.nasa.gov> To: mak@merit.edu CC: bjp@sura.net, regional-techs@merit.edu
Mark, the main problem for us is if you don't filter out the 97 some odd nets out of the AS 1957 routes you send us. If you are willing to do that, then we still don't have any new administrative load, and from NSI's point of view, we're happy. Did I read your statement right? If so, we'd definitely like to take you up on this offer!
See Steve Widmayer's message about the above.
You say: "For regionals using default, it isn't possible to prevent traffic from being sent from the regional to the CIX." This is true, given a certain set of assumptions, such as that the ENSS and CNSS's having the same set of routes. If the ENSS did not install the 97 nets etc, in it's routing table, then since it didn't have default, it would generate net unreachable messages and the traffic wouldn't flow. Given that I thought this kind of thing was possible given your implementation and use of IBGP and such, then this shouldn't be that hard. Again, please correct me if I'm offbase here.
While this might be possible this scheme would cause some administrative problems. Currently the backbone ENSS's and CNSS's carry full external routes in their tables, with each ENSS having an IBGP session with all other nodes. I think a better long term solution would be to try to move away from using default and on to full routing information exchange at AS borders (using aggregation of course). An example of the kind of problem we would run into using the ENSS-filtering approach is that all peers of that ENSS would have to use the same policy.
You certainly could argue that this sort of thing is necessary for ANS to serve it's member network's needs for CO+RE service. The real question is whether or not it is possible to do this and not increase the administrati
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load of non-participating regionals under your NSFNET agreement. The key to resolving the latter question is how much flexibility you guys have with the import and export of routing information into the routing tables of the ENSS's, and to be honest, I have only peripheral knowledge of the current way routes are sent around inside the T3 system (not because you guys are being secretive, just that I haven't been following this very closely due to work load problems).
Thanks, Milo
Still wearing my asbestos boxers (just in case), Mark