HP UNIX: JumboFrames

[LG Porter]

I have a Gigbit Ethernet 1000Base-SX card installed in a N4000 server. How do I turn off "Jumbo Frames" for this card?

[John Poff · Accepted solution]

Hi,

It sounds like you just have to make sure your mtu size is set to 1500. Here is a link to a thread about turning on jumbo frames:

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x7b9d4a988422d711abdc0090277a778c,00.html

JP

[Ajit Natarajan]

Jumbo frames refers to an MTU of 9000.

The default setting for 1000Base-SX MTU is 1500 so you wouldn't have to do anything if you didn't change configuration.

To find the current MTU of the link, first get its PPA from lanscan(1M). Then:

# lanadmin -m

If it shows 1500, you're set.

Otherwise, you can use lanadmin to change the MTU:

# lanadmin -M 1500

You should also check your configuration file. Depending on the card you're using, this file can be different. Look at HP_IGELAN_MTU in /etc/rc.config.d/hpigelanconf if you're using an A6847-60101 card. Look at HP_GELAN_MTU in /etc/rc.config.d/hpgelanconf if you're using the A4926A card. You can use ioscan(1M) to determine which card you're using.

The INTERFACE_NAME parameter will list the PPA of the interface. Make sure that the corresponding MTU parameter is empty or set to 1500.

That should do it.

Thanks.

Ajit
HP Gigabit Ethernet