Switches not able to ping each other n same VLAN over L2 circuit

[Glenn R]

Hi,

I have a strange issue where I am hoping the community can comment and help me.

What I have is 4 devices split across two sites over a L2 circuit and I am having issues pinging end to end. To explain more the topology is as follows:

 4500-X VSS (eth1/1) <-> (gi 1/0/1) 3850-A (go 1/0/48) --- Layer 2 Circuit --- (gi 1/0/48) 3850-B (ten 1/1/3)  <--> (ten 5/7) 6807 VSS

All the switches are all configured with VLAN 759 and this vlan is allowed in all trunk interfaces. All the interfaces above are mode trunk between the switches. Switch 4500-X, 3850-A and 6807 have SVIs with IP addresses for vlan 597.

I am able to ping from 4500-X to 3850-A but not to the 6807. Then from 3850-A I can ping to 4500-X and the 6806-A. Going from the 6807 again I can ping 3850-A but not the 4500-x switch.

Any suggestions ? 

[Reza Sharifi]

Hi,

Are all the devices in the same subnet?

Is there any default route or default-gateway configured on the 3850-A?

Can you post config (show run) from the 3850-A?

HTH

[Glenn R]

Hi,

Yes the devices except 3850-B have SVIs with IP addressing in the same subnet

6807 - 192.168.241.19/28

4500-X - 192.168.241.18/28

3850-A - 192.168.241.20/28

3850-B - No IP address

As I mentioned all devices have VLAN 759 for L2 and then the above for L3 which is in the 192.168.241.16/28 subnet.

Connectivity between all devices is configured as trunk interfaces and the VLAN 759 is allowed over all connections.

Tech support from the ISP will not help as the ping from switch 3850-A to the 6807 CORE on the remote side proves that the VLAN is been sent over the L2 circuit.  

[Glenn R]

Also since these devices are all on the same VLAN I would expect not to have to use a default router or default gateway if I am pinging with a source interface of the SVI 759.

[Sigurbjartur Helgason]

Hi Glenn,

I've had a similar problem with a circuit like that when the carrier had placed a limit on the number of MAC addresses they would accept/learn from us. It occurs to me that they might only be accepting a single MAC address from you.

Sigurbjartur

[Palani Mohan]

Glenn

The response you got from your ISP is typical of Tier-1 tech support. You may want to tell them you would like the problem to be escalated to Tier-2 because you approached the vendor(Cisco) and that they claim that all is well with the equipment config.

I hate to be the customer who is caught between the provider and the vendor, but then it is not anything new.

Going by what you described, for a "Layer-2 network" with trunk configured correct allowing vlan 759, another approach to take with the provider is to ask them to share the show mac-address-table (or its equivalent output) as seen at their end.  Usually, this level of interaction would lead to tier-2 getting engaged.

I wish you the best .... Palani

[Palani Mohan]

Hi Glenn

Assuming the config is ok at your end, I suggest that you involve the Tier-3 Tech Support from the provider. If they all is well at their end, call Cisco/TAC and get a 3-way conversation going.

Hope this helps ... Palani