CDP native VLAN mismatch

[Tomas]

Hello, I am having trouble with native VLAN mismatch between two Cisco switches. I am confused why other manufacture switches works, but Cisco don't. Can I blame CDP here and I hope there is a solution for this? Thank you very much! Tomas

[Reza Sharifi · Accepted solution]

Hi,

The Native vlan needs to be the same for both switches. On the 3750 the native vlan is 35 and on the 2960 the native vlan is 1. Try changing 1 to 35 on the 2960 and test again.

HTH

[Tomas]

But in this case, in a middle of two Cisco switches we have "magically" transferred from native VLAN 35 to untagged VLAN 1 on D-Link switch. Is that correct to configure native VLAN 35 on the end of 2950?

Maybe I am misunderstood the conception of native vlan and D-Link untagged VLAN.

[Reza Sharifi · Accepted solution]

I am not familiar with D-Link switches, but on Cisco switches the native vlan must mach between devices. Try changing the 2960 side and test.

[Tomas]

Problem was solved then native VLAN 35 was configed on C2950. Plus, all other ports configured to access vlan 35. By the way, CDP was disabled on both sides. Because C3750 screams with STP.
Really mysterious configuration here. Best practice is to use one brand switches.. 

[Joseph W. Doherty]

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Posting

Yes, you can most likely "blame" CDP.

Although you can intentionally use different native VLANs on a trunk (just as you can use different access port VLANs), it would usually be due to an misconfigured set up.  This is why CDP flags it.

If the mismatch is intended, either you live with the reoccurring CDP messages, or you disable CDP on one of the two ports.