Support of Jumbo frames by NIC

bzlaskar · 02-21-2007, 11:31 PM

Hi All,

Is there is any command in Linux which will let me know
whether my NIC supports Jumbo frame or not ?

macemoneta · 02-22-2007, 01:05 AM

If you try to set the MTU larger than the supported value by the driver or hardware, it will be rejected:

Code:

# ifconfig eth0 mtu 9000
SIOCSIFMTU: Invalid argument

bzlaskar · 02-22-2007, 05:27 AM

I tried the command and got the following output.

$ ifconfig eth0 mtu 9000
SIOCSIFMTU: Operation not permitted

So , Jumbo frames are not supported by my NIC.

But if I set the MTU size untill 7200 ,

sudo ifconfig eth0 mtu 7200

it is accepting . But from 7210 , it is not accepting.

$sudo ifconfig eth0 mtu 7210

SIOCSIFMTU: Invalid argument

As far as I know , the MTU for Ethernet NICs possible is
1500.

On what basis it is supporting untill 7000 . Please let
me know.
The driver information for my NIC is as follows.

$ sudo ethtool -i eth0
driver: r8169
version: 2.2LK-NAPI
firmware-version:
bus-info: 0000:01:02.0

macemoneta · 02-22-2007, 10:27 AM

Any value over 1500 is a jumbo frame. Your NIC supports up to 7200 octet jumbo frames.