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Re: Community NO-EXPORT
No, BGP synchronization does indeed refer to the requirement that the destination network be available via the IGP. If it were just the BGP NEXT_HOP value it wouldn't be of much use, as intermediate nodes perform forwarding based on the DA in the packet and [if not synchronized] won't find a match. As a result, the packet will be discarded. Of course, most folks simply have full mesh IBGP (perhaps via RR or confeds) and so there's no reason too enable [or not disable] BGP synchronization. -danny > Color me confused, but isn't the synchronization waiting on the > NEXT_HOPs showing up in your IGP, not the actual BGP route? > > After all, the issue is this: > > BR-A - (your internal network) - BR-B > > A route shows up at BR-A with a nexthop of some interface on BR-A > (or the loopback interface of BR-A). It is then propogated via > iBGP to BR-B. > > It is only unsafe to install said route and propogate it BR-B's peers > if the route's nexthop is not reachable by BR-B. > > This is a far cry from having to inject your BGP into your IGP. > > I will note that this isn't how Cisco has it documented, and I don't know > how they actually treat the sync issue. The documentation actually > says it does wait for the route to show up in the IGP.