26 Jun
1996
26 Jun
'96
10:49 a.m.
Other ISPs who happen to be in position to control physical routing of circuits use IP-level rerouting to attack the problem.
The IGP rerouting with modern link-state IGPs is sub-second so the redundancy of interior paths is easy to achieve (perticularly if you use tricks like BGP confederations which eliminate need to recompute iBGP routing in case of IGP changes).
Vadim, Can you be more specific about this? How do you avoid the recompute and also avoid persistent routing loops after a topology change?
The hard part is exterior routing where topology changes require massive crunching of BGP tables. Multiplying paths actually makes the problem worse.
You bet! Erik