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.
The description of RFC4271 for "resolvable", I am confused whether it
includes only route reachable, not includes host address reachable, does anyone
clearly understand it?
My test case:
BGP4----------------------------------------------------------BGP4 peer
set next hop:1560::28
BGP4 peer route table :
1560::/64 unicast [direct2 09:03:52.007] * (250)
dev A6IF1 --------------------------------------------------------the
address of interface is 1560::15/64 ,generate direct route
unicast [bgp4 09:24:36.872 from 1560::26] (200) [?]
via 1560::28 on A6IF1
-------------------------------------------------------the route is resolved in
BGP4 peer based in brid, but the address the interface of BGP4 peer is
1560::15, not 1560::28, NDP is not successful.
Thanks
Arvin
