Cisco IOS: How to view MAC addresses on an Ethernet pseudowire

Question

With two Cisco ME3600 (or similar MPLS & VPLS capable devices) running recent code [15.3(3)S], is it possible to show the MAC addresses passing over a standard MPLS encapsulated xconnect?

In the lab as an example I have configured an xconnect from an EVC on Switch1 to an SVI on Switch2 with Switch2 having an access port in the same VLAN (VLAN 1);

Switch1:
interface gi0/18
 switchport trunk allowed vlan none
 switchport mode trunk
 service instance 1 ethernet
  encapsulation untagged
  xconnect 1.0.0.2 123456 encapsulation mpls

Switch2:
int gi0/18
switchport
switchport access vlan 1

int vlan 1
xconnect 1.0.0.1 123456 encapsulation mpls

Everything works fine. I have a test PC connected to each end of the pseudowire which can ping each other and the IP assigned to the SVI for VLAN 1 on Switch2.

Is it possible to see their MAC addresses on the switches so I can see what MACs are being carried over this pseudowire?

To the best of my knowledge this is only achievable when using VFIs on IOS-XR (haven't tested VFI on IOS), is that correct?

Answer 1

This is correct: the pseudowire switching path does NOT do mac learning, so there's no way to populate that information. One possible workaround is to build a VFI that only has two ports. You will effectively end up with the same behavior (frames will just get bridged from one side to the other) but since you've now enabled the mac learning part, the system will store the MAC addresses learned from each side. One word of caution here: make sure you have enough resources on the system to learn all the MAC addresses. Most pseudowires don't actually have all that many MAC addresses, but some can/do.

Answer 2

It turns out this can't be done simply because pseudowire data plane traffic doesn't interact with any control plane logic in that MACs for example, aren't learnt. Although I knew this, as pseudowires are a point-to-point L2 bridge essentially I was hoping there may be a way to see something, anything!

Without the use of an VFI MACs aren't learnt. Sadly though I have no official Cisco documentation to back this up, I've just been told this by friends and collleagues who's technical knowledge I highly value.