[c-nsp] me3600 : l2protocol forward stp on EVC

[BASSAGET Cédric]

Hello,

I need to interconnect two L2 domains. I was planning to use a me3600 for
this :

interface port-channel 1
...
 service instance 1439 ethernet
  encapsulation dot1q 1439 second-dot1q 1-4094
  rewrite ingress tag pop 1
  bridge-domain 1439
 !
 service instance 1440 ethernet
  encapsulation dot1q 1440 second-dot1q 1-4094
  rewrite ingress tag pop 1
  bridge-domain 1439
 !

Works fine, hosts on same C-VLAN on both sides of bridge-domain can ping.

As I need my interconnection to be STP-transparent, I tried to add
"l2protocol forward stp" on these 2 EVCs.

This resulted in side effects on my backbone, and I saw STP events on the
other side of my port-channel (n3k switch) :
2020 Dec  8 06:32:37 N3K-eqx-pa3-1 %STP-2-BLOCK_PVID_LOCAL: Blocking
port-channel1 on MST0000. Inconsistent local vlan.

Question : why is the port-channel affected by l2protocol forward on an EVC
?

I guess I'll have to remove the "second-dot1q 1-4094" to allow untagged
trafic on EVCs, and make L2CP work correctly.

Is this the right way to do ?
Thanks for your help.
Regards,
Cédric