jumbo frames on 3750s & nexus 7K

[gavin han]

Hi, I'm new to jumbo frames. I've to enable it on 3750 and nexus 7K switches. what are the steps involved? can we enable jumbo frame per port instead of enabling globally? i.e. we will only have few ports that will be using jumbo frames, rest of the ports will be using default 1500 MTU size.

[Reza Sharifi]

On 3750 series switches, jumbo frame can only be enabled globally and not per port.

here is the command:

Switch(config)#system mtu jumbo ?

  <1500-9198>  Jumbo MTU size in bytes

On the 7K series, it can be enabled per port. You would need to use a policy:

here the config guide with example:

http://www.cisco.com/en/US/products/ps9670/products_configuration_example09186a0080b44116.shtml

HTH

[gavin han]

Thank u so much. How about 6500 switch. Can we enable jumbo frames per port on 6500 switch?

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[mahmoodmkl]

Hi

AFAIK its the same u  need to enable it on system rather then on per port.

Thanks

[Reza Sharifi]

For 6500, you can enable it per port.

HTH

[gavin han]

Thanks again. This 3750 has one uplink where we need jumbo frames. It is connected to other switches as well which don't have jumbo frames enabled. So traffic from this 3750 to other switch be sent out as jumbo frames or would it be fragmented to 1500 bytes mtu by those switches?

To get jumbo frame functionality, do we have to enable it in our complete environment?

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[Reza Sharifi]

If one link from the 3750 is connected to another switch that is not jumbo frame enabled, at the minimum, you need to configure jumbo frame on the link on the other switch.

To get jumbo frame functionality, do we have to enable it in our complete environment?

correct.  If you need the functionality, then you can enable in all your devices.

HTH