Jumbo Frames on Nexus 93180YC-EX, 5672UP, and perhaps others

Cisco’s documentation implies that to enable jumbo frames on the 5K and 9K line, one must simply set mtu 9216 on the physical and logical L1/L2 interfaces:

Configure and Verify Maximum Transmission Unit on Cisco Nexus Platforms

However, currently working with the 93180YC-EX and previously worked with the 5672UP, I can tell you that both are actually based on the obscure 6K line.

And, per the 5672UP documentation, in order to get jumbo frames, you must do this additional step:

policy-map type network-qos jumbo
  class type network-qos class-default
          mtu 9216
system qos
  service-policy type network-qos jumbo

After applying this, also do a set mtu 9216 on the on the L3 SVIs:

Switch(config)#interface Vlan200
  no shutdown
  mtu 9216


Switch# show interface vl200
Vlan200 is up, line protocol is up, autostate enabled
  Hardware is EtherSVI, address is 70ea.1a44.d0a7
  Internet Address is 192.168.200.1/24
  MTU 9216 bytes, BW 1000000 Kbit, DLY 10 usec,

Switch# show interface et1/17
Ethernet1/17 is up
admin state is up, Dedicated Interface
  Belongs to Po17
  Hardware: 100/1000/10000/25000 Ethernet, address: 70ea.1a44.d0b8 (bia 70ea.1a44.d0b8)
  Description: Storage Filer
  MTU 9216 bytes, BW 10000000 Kbit, DLY 10 usec
  reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, medium is broadcast
  Port mode is trunk
  full-duplex, 10 Gb/s, media type is 10G

 

93180YC – Jumbo Frames