Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

Configuring jumbo frames.

Hi,

I have configured jumbo frames sized as 9198 in a 4948 switch using interface config mode inc the ether channel configured as trunk port.But after 10 min the switch stopped forwarding the frames.I would like to know is it possible to pass jumbo frames through a trunk or ether channel port between two switches.If so is this te possible wway to do this.One more doubt , what is the diffrence in configuring jumbo frames in global mode (system mtu < size> ) and int config mode (mtu <size>).Please help.

10 REPLIES
Cisco Employee

Re: Configuring jumbo frames.

Hi Anil,

Jumbo frames can be configured on etherchannel which are working in trunking mode. Jumbo frames are supported on nonblocking Gigabit Ethernet ports, and EtherChannels.

If you want to enable jumbo frames globally on all the ports so that you need not configure individually on all ports use "system mtu" command but if you want it for individual interface then configure on per interface basis.

But if you have configured on global mode with system mtu command and also on per interface basis then per-interface mtu command takes precedence over the system mtu command.

Can you specify if you have specified or changed mtu on interface basis or globally.

Also can you paste or attach the sh version from the switch.

HTH

Ankur

Re: Configuring jumbo frames.

Hi Ankur,

Thank you for the reply.I have conbfigured in all the port , but using the interface config mode using the range command.Alos configured the uplink port which is an ether channel trunk port.But after doing this I can't able to ping to outside from the switch even to Default GW.So i just reset MTU to 1550.

Sh version

Cisco Internetwork Operating System Software

IOS (tm) Catalyst 4000 L3 Switch Software (cat4000-I9S-M), Version 12.2(20)EWA,

RELEASE SOFTWARE (fc1)

Technical Support: http://www.cisco.com/techsupport

Copyright (c) 1986-2004 by cisco Systems, Inc.

Compiled Wed 08-Sep-04 18:41 by kellythw

Image text-base: 0x00000000, data-base: 0x01224644

ROM: 12.2(20r)EW1

Dagobah Revision 225, Swamp Revision 4

sw-200-cr1(E9) uptime is 13 weeks, 2 days, 21 hours, 40 minutes

System returned to ROM by power-on

System image file is "bootflash:"

cisco WS-C4948 (MPC8245) processor (revision 0) with 262144K bytes of memory.

Processor board ID FOX0850056A

MPC8245 CPU at 266Mhz, Fixed Module

Last reset from PowerUp

3 Virtual Ethernet/IEEE 802.3 interface(s)

48 Gigabit Ethernet/IEEE 802.3 interface(s)

511K bytes of non-volatile configuration memory.

Configuration register is 0x2101

Thanks alot,

Anil.

Cisco Employee

Re: Configuring jumbo frames.

Hi Anil,

Make sure the port to which your uplink switch is connected also support jumbo frames. I believe you might have set the jumbo frames on uplink etherchannel ports but not on the device interface to which your etherchannel terminate.

If that device does not support jumbo frames then its better you move it back to 15xx.

HTH

Ankur

*Pls rate all helpfull post

Re: Configuring jumbo frames.

Hi Ankur,

with this jumbo frame discussion i would also like question that, core switch 3750 jumbo frames enabled(as this switch doesn't support individual jumbo frames per port, so enabled jumbo frames globally), all servers connected on this switch are jumbo frames enabled, now one of the port is a trunking port connected to 2950T-24, all clients in this switch are 100Mbps, so if i enabled jumbo frames globally, it will enabled only in the 1000Mbps port or all the ports including 100Mbps as well as 1000Mbps?

Cisco Employee

Re: Configuring jumbo frames.

Hi Anand,

Correct me if I am wrong, I believe you are looking for Jumbo Frame support on 2950T-24 switch.

AFAIK 2950 does not support jumbo frames and can max support baby giant frames upto 1530 and that too specific models

http://www.cisco.com/en/US/partner/products/hw/switches/ps700/products_configuration_example09186a008010edab.shtml#c5

Are you able to configure more that this on your 2950?

Regards,

Ankur

Re: Configuring jumbo frames.

.

Re: Configuring jumbo frames.

Hi Ankur,

I think I configured jumbo frames only in the port channel.Not in the corresponding member physical interface.I have to check this out.Thank you for the response you have given.

Anil.

Re: Configuring jumbo frames.

Hi Ankur,

Your right that 2950T-24 doesn't support more that 1500 bytes, so if i enable jumbo frames on 3750, what will happen if that 3750 is connected to 2950T-24? will it cause any data packet loss as 1 side 9000(3750) & other side 15000(2950)?

Cisco Employee

Re: Configuring jumbo frames.

Hi Anand,

I believe you are connecting your 3750 to 2950 via gig ports. Its true that if you have enabled system mtu to 9000 on 3750 and because 2950 does not support jumbo frames, there will be packet loss.

It is always recommended that the ports which are having a communication between each other have to have the same MTU.

HTH

Ankur

*Pls rate helpfull post

Re: Configuring jumbo frames.

certainly the problem will not be solved, as i need to looking for a 2950 switch will will support jumbo frame. any how thanks ankur for your replies. certainly will rate the post .

1014
Views
5
Helpful
10
Replies
CreatePlease login to create content