We are looking to introduce some static routing to address OSPF instability issues ( long story about multicast traffic over AT&T Switched Ethernet service ).
Basically, I want a static route from a hub router out to a spoke router but I want the route to be withdrawn if the hub loses connectivity to the spoke router because there is an alternative path.
So on the hub router I have:
enable iproute bfd 10.254.101.2 vr VR-Default
configure iproute add 10.1.0.0 255.255.0.0 10.254.101.2 bfd
on the spoke router I just enable the BFD client:
enable iproute bfd 10.254.101.1 vr VR-Default
With this done I can see the route as follows:
Ori Destination Gateway Mtr Flags VLAN Duration
#s 10.1.0.0/16 10.254.101.2 1 UG---Spum--f- MetroA 0d:20h:50m:38s
Flags: (b) BFD protection requested, (B) BlackHole, (c) Compressed, (D) Dynamic, (f) Provided to FIB, (G) Gateway, (H) Host Route, (l) Calculated LDP LSP,
(L) Matching LDP LSP, (m) Multicast, (p) BFD protection active, (P) LPM-routing,
(R) Modified, (s) Static LSP, (S) Static, (t) Calculated RSVP-TE LSP,
(T) Matching RSVP-TE LSP, (u) Unicast, (U) Up, (3) L3VPN Route.
The "p" flag indicate that BDF protection is active and the "f" that the route is in the FIB.
If I actually pull the cable out between the devices:
Ori Destination Gateway Mtr Flags VLAN Duration
s 10.1.0.0/16 10.254.101.2 1 -G---Spum---- MetroA 0d:20h:54m:19s
The route is Down and not in the forwarding database. If I disable the BFD client on the spoke router so as to bring down the BFD session, I get the following on the spoke router:
#s 10.1.0.0/16 10.254.101.2 1 UG---Sbum--f- MetroA 0d:20h:58m:51s
The "b" flag indicates that BFD protection is requested ( but not active ). The "f" flag is set so the route is still in the FIB.
This seems to be wrong. BFD is working in terms of detecting a loss of connectivity to the remote client:
show bfd session
Neighbor Interface Clients Detection Status VR
=====================================================================
10.254.101.2 MetroA ----s 3000 Down VR-Default
=====================================================================
Clients Flag: m - MPLS, o - OSPF, s - Static
but the expected route withdrawal does not occur.
