Posted on October 26, 2021 12:50 pm
 |  Asked by Duc Le
 |  68 views
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Hi,
I have a lab running vEOS 4.27.0F. I am trying to configure VPWS with port-based service. If I understand correctly, all traffic would be sending through the PW. But it seems that the 2 CE cannot join the same spanning -tree domain. I would expect that 1 CE is the root of the spanning-tree. Pings between CE works without any issues.
I wonder in VPWS port-mode, does BPDU also sent out of the pseudowire? And if spanning-tree works across the VPWS?
I suspect it might have to do with the lab environment. So just want to confirm.
My lab is very simple as well. Just running MPLS LDP.

Thanks.

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Posted by Aniket Bhowmick
Answered on October 27, 2021 11:36 am

Hi Duc

Thank you for reaching out on EOS forums.

We do forward BPDUs in port-mode VPWS, see the below image from the TOI- https://eos.arista.com/eos-4-26-0f/evpn-mpls-virtual-private-wire-service-vpws/

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You can see in above image that in Port Mode, STP packets are forwarded.

Have you tried taking a packet capture on the CE (which should receive BPDU from STP root CE) ? If not, can you try taking a capture and see if the CE is receiving BPDU packets from the other CE?

Also can you share the output of "show patch panel <patch-panel-name> detail" from both PE device?

Regards

Aniket

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Posted by Duc Le
Answered on October 28, 2021 9:42 am

Hi Aniket,

I have tried to do packet capture on several devices and it seems that the PE did receive the BDPU with the MPLS label but then it not forward it to the CE. So to your question, the CE did not receive the BPDU.

PE1#show patch panel PATCH1 detail

PW Fault Legend:
ET-IN - Ethernet receive fault
ET-OUT - Ethernet transmit fault
TUN-IN - Tunnel receive fault
TUN-OUT - Tunnel transmit fault
NF - Pseudowire not forwarding (other reason)

Patch: PATCH1, Status: Up
Connector 1: Port-Channel1
Status: Up
Connector 2: BGP VPWS VPWS-1 Pseudowire PW1
Status: Up
Local MPLS label: 132768
MTU: 0, Control word: Y
Neighbor 5.5.5.5, MPLS label: 132768
Tunnel type: LDP, Tunnel index: 1
MTU: 0, Control word: Y
Neighbor 6.6.6.6, MPLS label: 132771
Tunnel type: LDP, Tunnel index: 4
MTU: 0, Control word: Y
EVPN VPWS type: port-based
Flow label used: transmitted and received

PE3#show patch panel PATCH1 detail

PW Fault Legend:
ET-IN - Ethernet receive fault
ET-OUT - Ethernet transmit fault
TUN-IN - Tunnel receive fault
TUN-OUT - Tunnel transmit fault
NF - Pseudowire not forwarding (other reason)

Patch: PATCH1, Status: Up
Connector 1: Port-Channel1
Status: Up
Connector 2: BGP VPWS VPWS-1 Pseudowire PW1
Status: Up
Local MPLS label: 132768
MTU: 0, Control word: Y
Neighbor 1.1.1.1, MPLS label: 132768
Tunnel type: LDP, Tunnel index: 4
MTU: 0, Control word: Y
Neighbor 2.2.2.2, MPLS label: 132768
Tunnel type: LDP, Tunnel index: 5
MTU: 0, Control word: Y
EVPN VPWS type: port-based
Flow label used: transmitted and received

I attached the picture of the packet capture that shows the MPLS label as well as the show mpls lfib route command
I have a feeling that it might be because of the lab environment that I use(EVE-NG) so just want to cofirm the behaviour.
Br,
Duc Le

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Posted by Aniket Bhowmick
Answered on November 9, 2021 4:05 am

Hi Duc

We may need to do some deeper analysis of this as we do support VPWS in vEOS and we expect it to work.

Can you send out an email to support@arista.com to open a case and we can take further look into it.

Regards,

Aniket

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