Conditions
MLDP used as core tree protocol + MPLS TE as transport
Further Problem Description
I'm observing MPLS TTL behavior changes starting from IOS XE 16.7.1 and later (same setup working as expected up to 16.6.3).
My setup is mVPN - Profile 13 (MLDP core tree protocol).
CE1 — PE1 — P — PE2 — CE2
CE1 is RP and BSR.
The issue:
MPLS TE does not inherit TTL from inner label (which is MLDP-derived) and sending TTL as 1, it is causing traffic to be dropped on next hop and BSR messages not reaching remote PE which is one hope away - so multicast not working in this case.
Issue found during lab tasks, so no customer issues known so far. I see same issue on IOL and CSR1000v.
Attached capture between PE1 and P - mldp with mpls te.pcapng
- you can see first two packets with TE tunnel disabled (in this case only ?LDP? TTL).
- last two packets with TE tunnel enabled and TTL is 1 in outer label which is RSPV derived.
Also MLDP and TE statuses - mldp with mpls te.txt
PE1 config (PE2 configured identically) - PE1_config.txt
Is that buggy behavior or some extra config required (starting from 16.7.1) to inherit TTL from MLDP-derived label (as unicast works fine and TTL inherit properly in same setup with TE tunnel enabled)?
