said by rchandra:
Oh sure. There's almost always going to be some downtime. But hopefully it can be measured in seconds or minutes as compared to days or weeks for something like a (utility) power outage. It all depends on the engineering chosen.
BTW, thanks for that. I knew of the technology (BGP), but I have no practical experience in having to reroute traffic.
No problem. For BGP failover it depends on the peers (have to match timing) and varies depending on provider. BGP still fails-over in a matter of minutes though for the most part (Cisco's default timer is 3 minutes I believe), but is still slower than say EIGRP or OSPF which is almost instantaneous. A lot of organizations also run BGP internally if they have a large enough network.