> Bugs can be present at other places than an ASBR. Imagine the following very > ordinary network: > > AS100 --- [ ASBR2 --- AR3 --- ASBR4 --- ] AS500 > > ASBR2 will have iBGP routing exchange with ASBR4 by some means. This may be > an ordinary iBGP session, via a route-reflector, or whatever. > If AR3 is buggy but it is in the forwarding path between ASBR2 and ASBR4, > then ASBR4 potentially will send packets to AR3, yet AR3 has > treat-as-withdraw a route. ASBR4 is not subject to the bug, receives and > installs the iBGP-learnt route from ASBR2, and happily announces it to AS500. > > [SR] Ok. This however does not happen in bgp-free core (ASBR2 will tunnel > the packet to ASBR4 even if AR3 is in the forwarding path).
And we should also note that this can happen with ANY error recovery mechanism. Anytime AR3 and ASBR4 receive different information or process it differently, you'll have a problem. Also true with simple session reset: if AR3 detects an error and shuts down its iBGP connection, then ASBR4 won't know it and you've got a blackhole. Bottom line: this situation already occurs with session reset, will occur with treat-as-withdraw, and will occur with ignore-bad-messages. So, what was the point of this argument again? Tony _______________________________________________ GROW mailing list [email protected] https://www.ietf.org/mailman/listinfo/grow
