N5k Jumbo frames just on few ports

[andre.ortega]

Hello there,

How could I enable jumbo frames on Nexus5k just on few ports?

[Amit Singh]

Cisco Nexus devices support different MTUs per QoS group and we cannot represent the MTU
as an interface value.

You have to do it for the whole system.

switch(config)#policy-map type network-qos jumbo
switch(config-pmap-nq)#class type network-qos class-default
switch(config-pmap-c-nq)#mtu 9216
switch(config-pmap-c-nq)#exit
switch(config-pmap-nq)#exit
switch(config)#system qos
switch(config-sys-qos)#service-policy type network-qos jumbo

In order to check the MTU for an interface and a particular queue, you should use the
following command:

switch# show queuing interface ethernetX/Y

[andre.ortega]

Hello Amit, thanks for your help, but I´d like to configure just 4 interfaces to allow jumbo frames. Is it possible?

I can´t enable jumbo on my whole system...

Could I create a QoS group and associate it just to these ports?

[Amit Singh · Accepted solution]

Yes, you can apply it to just one or group-of interface for Layer3 , instead of the "system qos" interface just use "interface ethx/y".

For L2, you cannot set the MTU per interface but only system wide. The mtu is set under network-qos which can only be attached to system qos.

Hope this helps.

-amit singh

[andre.ortega]

Thank you so much Amit.

It totally answers my question.

[Amit Singh]

No problem Andre. Glad I was of help. Appreciate your rating.

Please continue to use the Cisco support forums for support.

Cheers,

-amit singh