EVC's between 2 ASR1002's

[tsheltonuk]

Hi Guys

I'm having a bit of trouble with L2 over MPLS via an EVC, one end connecting to a L2 WAN circuit over to a customer through a carrier, and therefore has an S-TAG (2096). Connected to our other PE is a circuit directly connected from out ASR to a customer's switch stack. 

Please could someone assist in reviewing the attached visio diagram and explaining how this can be configured correctly!

Many thanks!

Tom

[Francesco Molino]

Hi
can you plz share the config on R1 and R2?

[tsheltonuk]

Hi

R1:

int gi1 

 service instance 7000 ethernet

 encapsulation dot1q 2096 second-dot1q 120

 rewrite ingress tag pop 1 symmetric

 xconnect 192.168.212.3 7000 encapsulation mpls

R2:

int gi1

 service instance 7000 ethernet

 encapsulation dot1q 120

 xconnect 192.168.212.3 7000 encapsulation mpls

my thinking was just to pop the carrier tag off as it enters the network and add it back on symmetrically when it leaves, but to no avail...

Any help is appreciated.

Thanks

[tsheltonuk]

***CORRECTION***

R2:

service instance 7000 ethernet

 encapsulation dot1q 120

 rewrite ingress tag pop 1 symmetric

 xconnect 192.168.212.2 7000 encapsulation mpls

[Francesco Molino]

Hi,

Explain please why you're using vlan 2096 ? You want to do xconnect between 2 ASRs and 1 site is trunked with vlan 120 and the other untagged right ?

[tsheltonuk]

Hi 

VLAN 2096 is the tag imposed by the carrier, so we have no choice in that. Lots of circuits terminate on this interface with VLANs.

Thanks

Tom

[Francesco Molino]

Sorry the question wasn't what this vlan is for. You said that it was s-tag vlan. Mt question is more why are you using it on your service instance config.

You're doing a xconnect, that means encapsulating layer 2 over layer3. At least i can understand that you will use bridge-domain 2096 but no need to rewrite the vlan id.

Then on site A, the switch is in trunk and sure B in access right?

What is the status of your xconnect, what are the interface status of switches facing R1 and R2?

[tsheltonuk]

Hi 

We have to use it as that is the VLAN that our carrier uses to terminate the service. The carrier allows for secondary VLANs to be piped through. 

As a bit of back ground, both sides will be trunk ports, we are wanting to run several VLANs across our MPLS cloud. Xconnect's are up:

service instance 7000 ethernet
encapsulation dot1q 2096 second-dot1q 120
rewrite ingress tag pop 1 symmetric
l2protocol forward stp lldp
xconnect 192.168.212.2 7000 encapsulation mpls

TE-CR-1#sh mpls l2transport vc

Local intf Local circuit Dest address VC ID Status
------------- -------------------------- --------------- ---------- ----------
Gi0/1/3 Eth VLAN 2096/120 192.168.212.2 7000 UP

!

!

!

service instance 7000 ethernet
encapsulation dot1q 120
l2protocol forward stp lldp
xconnect 192.168.212.3 7000 encapsulation mpls

TN-CR-1#sh mpls l2transport vc

Local intf Local circuit Dest address VC ID Status
------------- -------------------------- --------------- ---------- ----------
Gi0/1/0 Eth VLAN 120 192.168.212.3 7000 UP

Regards

Tom

[Francesco Molino]

Ok usually, using the bridge-domain and creating the bvi will be enough.

Anyway your xconnect is UP. What is you problem?
Did you do a wireshark to see if traffic is passing through this xconnect?

[tsheltonuk]

You can't use a BDI and xconnect though?



There is no layer 2 connectivity.. Is my config correct for my desired solutuion?

[Francesco Molino]

Hi

I wrote maybe quickly but what I was saying is under your service-instance, you configure your bridge-domain and this bridge-domain will an interface vlan on which a xconnect can be build up.

Your xconnect is connect but no Layer 2 connectivity:
- Have you ran wireshark capture to see if packets are exchanged when initiating a communication?
- What are the interface status on both switches side? and what about spanning-tree?

In terms of configuration, the service instance seems to be ok but what are other configuration on the same interface?
It should look like something like that:
interface GigabitEthernet0/1
switchport trunk allowed vlan none
switchport mode trunk
service instance 7000 ethernet
encapsulation dot1q 2096 second-dot1q 120
rewrite ingress tag pop 1 symmetric