QinQ on 2970 how?

Question

Computer networks

Good afternoon!
Is it necessary to increase the MTU by 2970 for QinQ to work correctly? Or are there any workarounds.

Answer 1

First - QinQ is not supported on 2970. Feature Navigator to help you - tools.cisco.com/ITDIT/CFN/jsp/SearchBySoftware.jsp
Second - if you need to drive QinQ VLAN transit through 2970, then yes, be sure to raise the MTU by 4 bytes ( in the standard version 2 vlan tag - inner and outer tag).
;-)

Answer 2

Good afternoon! You can simply reduce the MTU size on the physical interfaces.

Answer 3

QinQ adds 4 bytes.
On L2, the concept of "fragmentation" does not exist.
How do you envision workarounds other than a general reduction in the size of package contents?

Answer 4

If nothing has changed and the switch considers the MTU without L2 headers, then the standard 1500 should be enough.