On 10/06/2011 11:37, Iljitsch van Beijnum wrote:
So it depends a little, but I still don't see any implementation leeway in RFC 2545:
On all competently constructed interior networks, ibgp will use loopbacks as the session endpoints. This means that the loopback address will be carried as the next-hop in the UPDATE messages rather than the link local address. Ok, you can do physical interface to physical interface on ibgp if you want, and if you do, good luck with that idea. For those bgp sessions which use directly connected subnets (e.g. most ebgp and badly configured interior networks), this is implementation dependent. Some stacks by default provide both the link-local and the global address; others provide just the global address; others still will provide link-local depending on interface configuration (e.g. the per-interface "ipv6 enable" command on IOS). Once the router has learned the next-hop, it may or may not choose to display it differently when you're displaying ipv6 forwarding information. Some router stacks implement implicit next-hop resolution for their own RIB to forwarding table; others don't. Some will display this information and others don't. So really, it depends. Nick