Nexus Jumbo Frames

[Adnan Khan]

Is Nexus 3K jumbo Frame required a switch reload? Default MTU is 1500 bytes.

policy-map type network-qos jumbo

class type network-qos class-default

mtu 9216

system qos

service-policy type network-qos jumbo

[Sergiu.Daniluk]

No, reload is not required.

[Adnan Khan]

Great one more question. The above configuration will enable to support jumbo frame by all layer 2 ports and also supports 1500 MTU and in layer 3 ports and SVI we need to manually specify jumbo MTU. Can you refer to any document that states no reload is required?

[Sergiu.Daniluk]

"The above configuration will enable to support jumbo frame by all layer 2 ports and also supports 1500 MTU and in layer 3 ports and SVI we need to manually specify jumbo MTU"

S.D.: That is correct, for Nexus 3048, the L2 MTU is set using the network-qos policy, while the L3 MTU is set manually on the SVI or L3 port.

"Can you refer to any document that states no reload is required?"

S.D. If reload is required for a specific command, usually a message is displayed after the command is applied. Which is not the case for qos commands.

Cheers,

Sergiu

[Adnan Khan]

If we have HW MTU:1500 will it support modifying 9216 bytes MTU?

PID: N3K-C3048TP-1GE

show queuing interface Eth1/33
Ethernet1/33 queuing information:
qos-group sched-type oper-bandwidth
0 WRR 100
qos-group 0
HW MTU: 1500 (1500 configured)

[Sergiu.Daniluk]

Eth1/33 is a Layer 2 or Layer 3 interface?

Cheers,

Sergiu

[Adnan Khan]

Layer 2 and I saw some 3k models also support per port MTU but this model I went into interface config and below but mtu was unrecognized

(config-if)mtu   (it was not configurable like that)

HW MTU: 1500 (1500 configured) what does that mean? HW does not support 9216 or not configured only

[Sergiu.Daniluk]

The N3K model you have only supports L2 MTU configuration using network-qos.

You can find more details about what models supports what here: https://www.cisco.com/c/en/us/support/docs/switches/nexus-9000-series-switches/118994-config-nexus-00.html

HW MTU - should be the currently configured MTU for that specific interface.

Stay safe.

Sergiu