MTU size 9216-9216 bytes

[vwolgel12]

Have 3-port etherchannel on gig interfaces between 2 6500 routes. These two 6500s uplink to 7206 running MPLS over Ethernet.

"mpls mtu 1530" is configured on 7206 interfaces connected to 6500s. Now I want to configure plain-vanilla "mtu size 1530" on

the (3) 6500 gig interfaces in the etherchannel. But when I type "mtu 1530" in config-if the router says invalid input, when i do

"mtu ?" it says <9216-9216> MTU size in bytes. (see attached) But,  If i do a "show int" on this interface, the MTU is 1500.  If I try the same

"mtu 1530" on another gig port on the same board that is not in use, the command is accepted. Why does the gig port in the

etherchannel not accept the "mtu 1530" command and another gig port on the same board does?

Gig card is: WX-X6748-GE-TX..

[Reza Sharifi]

Do you have the same issue with all physical links in that EtherChaneel?

All physical links in an EtherChannel must have the same MTU size.

[vwolgel12]

Yes, same issue on all 3 gig ports in etherchannel. The etherchannel has been in production for quite some time and there are no problems and yes all physical links in the etherchannel have the same MTU size which is 1500 bytes verified when I do a "show int" for all the ports. We want to run MPLS traffic over this etherchannel and wanted to increase the mtu size to 1530 to accomodate the MPLS labels so I just ran in to this mtu size issue. Here are my questions:

if the MTU size under "show int" says 1500 bytes, why do I get the message "MTU size 9216-9216 bytes" when I try to change the MTU size. I would expect the MTU size under "show int" to say 9216 bytes?