Support for Jumbo frames on Catalyst 6500

[NAVIN PARWAL]

Folks,

Reading documentation on CCO on how to enable support for jumbo frames on the catalyst 6500. Documentation talks about enabling it on per port basis. Can i enable support globally??? and not worry about enabling in on every port??

Also, would i have to reboot the switch for the change to take effect? 3550 series switch need to be rebooted after the support for jumbo frames is enabled.

Any help would be highly appreciated.

Thanks,

Parwal

[Harold Ritter]

Parwal,

- On the 6500, support for jumbo frames has to be enabled per port.

- You shouldn't need to reload your 3550 for the jumbo frame support to take effect.

Here's a good document discussing the support of jumbo frames on most Cisco switches. It might be the same as the one you are referring to but I'm posting it just in case.

http://www.cisco.com/en/US/products/hw/switches/ps700/products_configuration_example09186a008010edab.shtml

Hope this helps,

[NAVIN PARWAL]

Thanks for the response.

So i do not need to reload any of the switches 3550 or 6500 after enabling support for jumbo frame support??

Why would cisco have a global command to enable all ports on a 3550 and not have a similar command for 6500??

The document i was referrring to clearly says that on a 3550 you need to reload the switch for it to start supporting jumbo frame, is the document outdated?

Thanks

[Harold Ritter]

Parwal,

Given the 6500 is a core switch, I would think that enabling jumbo frames support globally could have far more impact than on the 3550, which is an access switch.

As far as the 3550 is concerned, my mistake. I just looked a bit closer at the URL I directed you to and it litteraly states:

"Changes to the System MTU will not take effect until the next reload is done."

Thanks for pointing that out,

[NAVIN PARWAL]

thanks for your response.

Is there any harm if i enabled support for jumbo frame for all ports on the core switch which is a 6500??

I will it is not break anything?

do you know the pros and cons of enabling and disabling jumbo frames?

[Harold Ritter]

Parwal,

A possible impact would be higher buffer memory allocation once the jumbo frame support is enabled on all ports. It shouldn't break anything if you have enough memory on the box.

On the other hand, jumbo frames support is usually required only on ports used for MPLS support. I therefore wouldn't see a need to enable on all ports by default.

Hope this helps,