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 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



Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s