BFD on PPP Multilink

[rrfield]

Hi, 

I have configured BFD between two routers connected with a PPP Multilink bundle of T1's.  The routers (one ASR 1001-X, one ISR 4331) both take the commands, but the BFD session does not come up.  Both routers are running IOS-XE 3.16.00.  Here's the config and the show bfd neighbors command...

ASR-1001-X#sh bfd nei  

IPv4 Sessions

NeighAddr                              LD/RD         RH/RS     State     Int

Good DS3 Neighbor 1                    12/1          Up        Up        Se0/1/0

Good DS3 Neighbor 2                     2/1          Up        Up        Se0/1/1

Bad PPP Multilink Neighbor           4098/0          Down      Down      Mu1

ASR-1001-X#sh run int multilink 1

Building configuration...

Current configuration : 250 bytes

!

interface Multilink1

 dampening 10

 ip address omitted

 ip ospf bfd

 mpls ip

 ppp multilink

 ppp multilink group 1

 bfd interval 50 min_rx 50 multiplier 3

 service-policy output WAN-OUT

end

Any assistance is appreciated.  Also, I tried configuring BFD on the individual T1 ports, but that didn't really do anything, doesn't even show up in the sh bfd neighbor output.

Thanks!

[Mark Malone]

Hi is your license advanced ip or advanced enterprise only works on those 2 with ASR routers?

[rrfield]

Yes, and BFD is working on other interfaces, this problem is specific to the MLPPP interface.

[rrfield]

Talked to TAC, BFD isn't supported on MLPPP.  Interestingly, I did set up a GRE tunnel over the MLPPP interface, and BFD does work on it.  So a tunnel over a LAG, only kinda convoluted :)

If anyone from Cisco reads this, maybe don't let the user configure BFD on the multilink interface if it's not supported.  just a suggestion!

[Mark Malone]

Thanks for updating good to know i couldn't find anything on whether it was or was not supported for mlppp its not in any documentation i checked for BFD or MLPPP standards