BGP log message issue when using MPSLoDMVPN and IOC XE 17.9.5a

[iamtonythompson]

So I get this BGP log message ie: (%BGP-4-vpnv4NH_IF:next-hop x.x.x.x may not be reachable from neighbor x.x.x.x - not a loopback.) on XE 17.9.5a, (the rest of network is 17.9.4a)

Its MPLSoDMVPN, and all the iBGP peers on this DMVPN are the interface tunnel IPAs.

I'm not aware of any connectivity problems at all, just curious about the message, previous explanation by Harold Ritter makes sense to me, as the iBGP peers from hub to spoke are on the same L3 subnet.

Just want to head off a problem is all... if it is a problem ie: should my iBGP peers be a loopback instead?

Thx, Tony

[balaji.bandi]

the rest of network is 17.9.4a  - you mean on this code that works ?

or only device have 17.9.5a and rest al 17.9.4a not work ?

how is your topology and  configuration looks like ?

[iamtonythompson]

Everything works, to the best of my knowledge, it's just that I receive this log message on the one device running 17.9.5a code, the other devices do not get this log message, and they are running 17.9.4a. 

The topology is DMVPN with DUAL Hubs and Spokes, or "DUAL HUB - Single Cloud". All Spokes and the 2 hub DMVPN tunnel are on the same L3 /26 subnet.

[MHM Cisco World]

Hi Tony

Thansk for add new post.

Now log message there is no issue about traffic are you sure about that?

If you do traceroute from lan in spoke to lan in other spoke are traffic always pass through hub or not?

What dmvpn phase you use ?

Can I see config of hub bgp RR ?

Thanks again 

MHM

[iamtonythompson]

MHM,

Thanks, yes it appears all traffic flows well, it's a production network for 10s of thousands of users, and I'm not aware of any problems. Traffic must traverse Hubs, as it is Phase 1 I guess, each spoke has only two DMVPN connections, ie: one to each of the 2 hubs. Unfortunately, I can't show/share the configuration. Basically, I only want to ensure my XE code 17.9.5a is good to push to the entire network, and that there are know issues because this is about 32 nodes to upgrade.

[Harold Ritter · Accepted solution]

Hi @iamtonythompson ,

This message should not be a problem is the 2 PEs are directly connected. The issue I explained before was for a topology where there is at least one device between the two PEs.

The following document still recommends using the loopback interface to establish the BGP session advertising the VPNv4 prefixes.

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/sec_conn_dmvpn/configuration/xe-16-10/sec-conn-dmvpn-xe-16-10-book/sec-conn-dmvpn-xe-16-10-book_chapter_010000.html

Regards,

[MHM Cisco World]

He dont use vpnv4 over mpls core 

He use mplsOdmvpn with ibgp

I think he need in RR next-hop-self all

But let wait his reply 

MHM

[iamtonythompson]

MHM,

This is true, ie: not using mpls core. Also, RR and next-hop-self are both employed. Network has been operational several months with now real big issues or problems, just the message, and I'll look to use Loopbacks per your recommendation. Thanks, Again.

[iamtonythompson]

Thanks very much, there is actually an L3 encryptor pair in the middle of the Hub and Spoke. Thanks for the recommendation, I think all is good, I'll look to using Loopbacks and get rid of the message. Thanks, Again