L2 Etherchannel issue between Nexus 5K Dual-Connected and Cisco 6500 VSS

[pramudiathegreat]

Hi Vpc & Vss experts, I've been fighting with Etherchannel issue between Nexus 5K dual-connected and 6500 VSS. I'm new in Nexus environment so I need your advises on this. The diagram & configs are as the attachment. I have to use GLC-SX-MMD set with 1Gb speed at Nexus port since my 6500 10G module (WS-X6716-10G-3C) has not came yet. The issue is, I cannot ping either from Nexus to 6500 or the other way around, I'm not sure why though the Portchannel status at both sides are up. However if I ping the Vlan 716 in 6500 from Nexus, it always fail. Nexus-5K-1# ping 172.27.16.1 vrf management PING 172.27.16.1 (172.27.16.1): 56 data bytes ping: sendto 172.27.16.1 64 chars, No route to host Request 0 timed out ping: sendto 172.27.16.1 64 chars, No route to host Request 1 timed out ping: sendto 172.27.16.1 64 chars, No route to host Request 2 timed out ping: sendto 172.27.16.1 64 chars, No route to host Request 3 timed out ping: sendto 172.27.16.1 64 chars, No route to host Request 4 timed out --- 172.27.16.1 ping statistics --- 5 packets transmitted, 0 packets received, 100.00% packet loss I'm looking forward for your advises on this. Thank you, Pram

[Peter Paluch]

Pram,

I haven't worked with Nexus switches yet so I may be wrong easily. However, after going over your configuration, the interface Vlan716 on your Nexus appears to exist in the global routing table, not in the "management" VRF. I do not see any other interface in the Nexus configuration that would be assigned to the "management" VRF. That would explain why your attempts to ping 172.27.16.1 from VRF "management" fail - because in that VRF, the Nexus has no IP interfaces.

You probably have to decide very cautiously if you want your interface Vlan716 to be in VRF "management", or if it should stay in the global routing table. I do not recommend moving the interface to a VRF before making sure that it will not cause any further connectivity issues.

Best regards,
Peter

[pramudiathegreat]

Hi Peter,

Thank for your prompt advise. Appreciate.

I'm also new in Nexus environment, so I am still doing trial & error.

You said my ping fails because of the VLAN 716 was not in the vrf management. Is the VLAN config should be like this ?:

interface Vlan716
  vrf member management
  ip address 172.27.16.2/24
  no shutdown

Best regards,

Pram

[Peter Paluch]

Hi Pram,

Yes, that is correct - the interface Vlan716 should be put into VRF management if you want to have IP connectivity in that VRF. Be cautioned, however, that once you move that interface into VRF management, it will no longer be reachable from any other VRF or from the routing table. This is the connectivity issue I have been talking about earlier. It depends on your network design if this behavior is desirable.

Best regards,
Peter