BFD Support on IP Unnumbered Interfaces? - ASR 9000

[MaxPeddy70543]

I wanted to make a post to inquire about support for BFD using IP Unnumbered interfaces on the ASR 9000 platform. 

I was conducting some tests in my lab using BFD with IP Unnumbered between an ASR 920 and an ASR 9010 router with OSPF as my IGP. When using IP Unnumbered between the two routers, the BFD session would flap. When using IP addresses instead of IP Unnumbered, BFD is stable. I found that BFD using IP Unnumbered interfaces appears to work fine when testing from ASR920 to ASR920.

In short, does the ASR 9000 platform support BFD using IP Unnumbered interfaces?

[Ramblin Tech]

Is the unnumbered address on the 9K in the same subnet as the address on the 920? If not, I believe you may be in a BFD Multihop use-case. IIRC, 9K only supports iBGP and eBGP clients with BFD-MH, and then only in async mode.

[MaxPeddy70543]

Thanks for responding.

The unnumbered address on the 9K is not in the same subnet as the 920. In this case, I am using /32 loopback interfaces.