L2vpn not carrying both customer mgt and tagged

[dgawaya1]

Dear experts, 
I have an issue on my l2vpn PEs. Everything works well and I can ping either side of the PEs when I have "enc dot1q vlantag" configured on the sub interface connecting to the CEs. 

...........................configs..................................

interface GigabitEthernet0/0/0/17.3520 l2transport
encapsulation dot1q 3520
...............................................................................

I have another requirement to configure customer management traffic as well (lldp, cdp...etc). I got a breakthru with this when I configured "enc untagged" and  either CEs had lldp visibility to each other. The problem is that this broke the CEs connectivity. 
At the moment it looks like I can only have one of the other and not both! 
My PEs are NCS540s running XR 


..............my configs ...................
interface GigabitEthernet0/0/0/17.3520 l2transport
encapsulation dot1q untagged
l2protocol cpsv tunnel

.........................

[MHM Cisco World]

Sorry you want to use tag or untag ?

And both side use same (tag or untag)?

MHM

[dgawaya1]

I want be able to ping between CEs as well as be able to carry lldp. At the moment it looks like I can only have one but not both. Hope I make sense.

[MHM Cisco World]

Sorry my point is why you change from tag to untag ?

MHM

[dgawaya1]

That’s the only way to make lldp between CEs work. Now I’m looking for a configuration that does both

[MHM Cisco World]

Try below

-Use tag

- Use lldp tlv port-id 

- Use native keyword in CE subinterface both site

Use above and check

MHM

[dgawaya1]

I configured the native vlan to be tagged on the CE 
....
7150-1#sh run int eth51
interface Ethernet51
switchport trunk native vlan tag
switchport trunk allowed vlan 3520
switchport mode trunk
.......................
I tried different lldp options on the PE interface that connects to the CE but did not achieve what I'm looking for 
...............

RP/0/RP0/CPU0:GH1EVCP12A_Test(config-subif)#lldp ?
destination Configure LLDP Destination MAC on the interface
enable Enable LLDP TX and RX on an interface
receive Disable LLDP RX on an interface
tagged Enable VLAN tagging on LLDP PDU on this interface
transmit Disable LLDP TX on an interface
.......................

[Ramblin Tech · Accepted solution]

Is your l2vpn offering a port-based or vlan-based service? If vlan-based, then it should not transport untagged l2 control protocols like lldp between CEs since, by definition, the service only carries vlan-tagged frames. With vlan-based services, multiple PWs can be muxed on the same attachment circuit using the vlan IDs as a discriminator. If this is a port-based service then all traffic, tagged and untagged, on the AC should be transported over the same PW, including l2cp (with proper l2 tunneling protocol config in place). 

IIRC, a port-based service (aka, vpws) is configured on the main interface with “encap default” and no vlan subinterfaces. The “default” keyword would match all frames, tagged and untagged. 

[dgawaya1]

Thanks @Ramblin Tech  enc default worked well. Here is my final config 
.......config .......................
interface GigabitEthernet0/0/0/17.3520 l2transport
encapsulation default
l2protocol cpsv tunnel
!
RESULTS: The 7150 (CE) Can have lldp neighborship as required on Eth51........

7150-1#show lldp neighbors
Last table change time : 0:00:24 ago
Number of table inserts : 13
Number of table deletes : 7
Number of table drops : 0
Number of table age-outs : 2

Port Neighbor Device ID Neighbor Port ID TTL
Et2 SYD1QAXER001.asx.com.au Gi1/0/2 120
Et2 SYD1QAXER001.asx.com.au Gi1/0/2.82 120
Et25 CMEEVCS1_Test GigabitEthernet0/0/0/0 120
Et51 CMEEVCS1_Test GigabitEthernet0/0/0/17 120
Et51 7150-2 Ethernet51 120
7150-1#