On Tue, Aug 21, 2018 at 01:43:58AM +0000, Arvin Gan wrote:
Ping, anyone known it ?:)
Thanks Arvin
From: Arvin Gan Sent: Monday, August 13, 2018 5:42 PM To: bird-users@network.cz Subject: BGP resolvable issue
Hi all,
In RFC4271, If the NEXT_HOP attribute of a BGP route depicts an address that is not resolvable, or if it would become unresolvable if the route was installed in the routing table, the BGP route MUST be excluded from the Phase 2 decision function. Actually, BGP protocol is implemented this option. I notice that resolvable is checked with "rt->attrs->dest == RTD_UNICAST" , that mean the check is depend on the reachability of route for NEXT_HOP. However, NEXT_HOP is a host address, not a subnet address, the resolvable checking in VRF is depending on ARP/NDP result for NEXT_HOP, if NEXT_HOP cannot be resolved for MAC, it should be unresolved.
Hi IMHO resolvability condition is completely unrelated to ARP/NDP. See RFC 4271 9.1.2.2, host route is resolved in the same way as regular route. NEXT_HOP is one IP address, but resolvability check does longest-matching prefix match to find matching prefix. -- Elen sila lumenn' omentielvo Ondrej 'Santiago' Zajicek (email: santiago@crfreenet.org) OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net) "To err is human -- to blame it on a computer is even more so."