Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

MPLS ping/traceroute between Nexus and 6500


We currently have a pair of Nexus 7K connected to a VSS pair of 6509 switches via a metro ethernet service. The Nexus is partitioned into two VDCs, one for the core layer and the other for distribution (the third is default with no user data). The distribution runs VPC for access aggregation and the core VDC is layer 3 only. The VSS pair of switches is a collapsed core. There are two metro ethernet circuits that we have configured as layer 3 ports (no VPC!) and we are running MPLS/VPN over these metro circuits with OSPF as the IGP. The distribution VDC and the VSS pair are PE routers with the core VDC acting as a P router.

The issue is reachability between the core VDC and the VSS pair. I cannot successfully MPLS ping/traceroute between loopback interfaces unless I force-explicit-null. I can however, MPLS ping/traceroute from the distribution VDC and the VSS pair without having to force-explicit-null. I checked several times and all my interfaces are labeled. I am thinking this is a PHP issue, but I can't confirm/deny that. Production traffic is working just fine through the core VDC except for this MPLS ping/traceroute problem. I'm afraid that this will make troubleshooting more difficult for people other than myself, so I am asking for advice on how to potentially resolve this.

Attached is a simple visio showing the connectivity overview.

Any help on this matter is greatly appreciated.

Thank you,

AJ Schroeder