If anyone is wondering: Heck with these labs teaching things like routing and BGP by just plugging routers together. I'm probably going to end up building a scale internet model (if I can) with all the layers and working parts and O̶̩̐̊h̴͉́̉ ̶͍͔͙͛́̓g̴͓͕̟̍o̸̩͆̌ͅd̶̡͇̰̍̃͌ ̶̳̈́̐͑h̵̨̯̃̑e̷̢͙̳̓̃̕l̴̨̳̃̓͂p̸͚̼̍̍ ̵̘͉̇̇m̴͙̟͙̽̓e̶͈͇̋́ ̵̢͔̏̌̀p̴̺̗̗̌ļ̶͍̿ĕ̵̪ȧ̴̡̯͍s̴̲̞̎e̵͕̦̽.
Excuse me while I brainstorm out loud.
The nice thing about this is that, in theory, not every PE router needs a copy of the global routing table, only the backbone routers and ASBRs do. Of course, that means having multiple areas.
In the real world this is a stubby area, or basically a dead-end in the topology. The ABR for the stubby area will re-write the LSAs it gets so that everything in the area uses them as the default route.
Problem, the PE is still technically an ASBR.
Solution: NSSA. a Not-So-Stubby Area seems to be the combination I'm looking for. ASBRs are still, well, accepted, and can send their routes to the ABR, and the ABR acts as a gateway for the entire area. Ergo, the PE router itself (ASBR) doesn't need an entire copy of the routing table, it just sends anything from the CE to the ABR, and that can figure out the correct path across the backbone to the other ASBR with a connection to the destination AS.
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