Jumbo frames on PE 1950

Peter J Milanese PMilanese at nypl.org
Mon Sep 22 03:57:06 CDT 2008

Once again, also make sure your network allows for jumbos. Cisco defaults to 1500, most reject over 1500.  Not sure of your network setup.

----- Original Message -----
From: christian.peper
Sent: 09/22/2008 10:22 AM ZE2
To: <linux-poweredge at dell.com>
Subject: RE: Jumbo frames on PE 1950

> -----Original Message-----
> From: linux-poweredge-bounces at dell.com 
> [mailto:linux-poweredge-bounces at dell.com] On Behalf Of Matt Lawrence
> Sent: Saturday, September 20, 2008 10:33 PM
> To: Linux-PowerEdge at dell.com
> Subject: Re: Jumbo frames on PE 1950
> Tom Pierce wrote:
> > Matt,
> > You need to have your ethernet network support 9000 MTU. 
> > Most are not configured for it.
> > You have to configure the switch/router(s) to pass on 9000 mtu
> The switch is configured to handle a MTU of 9000
> > ifconfig eth0 will tell you if your machine ethernet card 
> > is capable 
> > of setting a mtu of 9000. Usually when you set it it wither works or

> > it tells you that the driver does not support 9000 byte packets.
> That works just fine.  Also, the "card" is actually the 
> onboard NICs in the 1950.


I checked the web (google for "Broadcom NetXtreme II 5708 jumbo frame"
and Dell certifies support for Jumbo frames.

However, a bit further down I found this:

It says this (#39 in the FAQ):
Linux: Load the bcm5700 module using the mtu argument. Jumbo frames can
also be configured using ifconfig. Read the "Module Parameter" section
of the release.txt file for valid parameter ranges and further details.
View the ifconfig man page for help with ifconfig.

Or you may need more recent drivers than the one bundled with CentOS...

Hope this helps,

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