L2 Link configuration

[engineer_msu]

Dear Friends,

We have taken a Layer-2 Point to Point Link from Service Provider.

Service Provider has provided the link and tested by connecting Laptop Both Sides.

Site-A: 192.168.254.101/30

Site-B 192.168.254.102/30

We are able to ping the Laptops.

But when I connect the Links on Cisco Switch, we received 802.1Q BPDU and Provider requested us to make the configuration as Trunk. Attached is the configuration.

We are not able to reach Site-A to Site-B IP. Service Provider is saying there is no issue from their side, I dont find any issue at my configuration side.

Please help to understand, where exactly is the issue.

Please note that L2 VLANs are created at both core switches

[Richard Burts]

You have configured different VLANs on each end. If this is a point to point layer 2 connection then the VLAN on each end should be the same VLAN. Either put both into 330 or into 332 (or both into what the provider told you about VLAN ID).

HTH

Rick

[engineer_msu]

Dear Richard,

These two different VLANs are provided by Service Provider.

Service Provider is saying that as we are able to ping end to end with laptops at both end, there is no issue with reach-ability.

I am confused as we are able to ping the remote site when we connect laptop, but not working when connected to switches.

[Richard Burts · Accepted solution]

In most implementations where you are configuring switch ports and trunks, having different vlans configured on each end of the connection would cause problems. But if you are sure that the service provider said to make it different on each end then we will assume that this is the way that it is intended to be.

I have been thinking about the fact that it works when you connect laptops and you were able to ping. Many laptops do not process vlan tagged frames. So I am wondering if the frames processed by the laptops were un-tagged. If the vlan you are processing in each trunk were the native vlan then that would allow the connection to be tagged but the frames processed by the laptop would be un-tagged. Perhaps you can change the switch configurations making vlan 330 and 332 the native vlans in their trunks?

HTH

Rick 

[engineer_msu]

Dear Sir, I have checked the debug output and found that both sides have same VLAN 330. It was wrong communication from service provider.

I changed the VLANs and made the VLAN as native VLAN for the trunk ports which were connecting the links.

The Link is working now.

Thanks for your expert help to resolve this issue.

[Richard Burts]

I am glad to know that you have resolved the problem and that my advice was helpful. It makes much more sense to me that the vlan should be the same on both ends and it is strange that the provider would have communicated that incorrectly. Thank you for using the rating system to mark this question as answered. This will help other readers in the forum to identify threads with helpful information.

HTH

Rick