Error number 223 encountered when changing MTU size

[Khalil Ahmed]

Hi, I am trying to change the MTU size on one of my rx2620 Unix servers. The server is running HP-UX 11.23 (v2).

When I tried to change the MTU size I got an error number 223.

The attachment gives details of the lanscan & lanadmin commands I ran. Please have a look and see if I'm doing anything wrong, eg am I missing a step?... do I need to do this in single user mode?... do I need to disable the card before I make the change or re-boot the server after I make the change? etc

Thanks for your help in advance.

Khalil

[Prashant Zanwar_4]

I am not sure how safe it is do on a UP card..

-M mtu_size Set the new MTU size of the interface corresponding to PPA.The size value must be within the link specific range. You must have superuser privileges.

Why dont you try on cards which are in down state. And do you know what are allowable MTU's for your link. ?? First check that and try on a interface with state down.

Regards
Prashant

[Antonio Cardoso_1]

Khalil,
look at thread
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=202869

Ravi's response stated that
"For 100BT adapters, i.e., those adapters controlled by the btlan driver, the MTU can be set as low as 257 bytes. Any lower than that is not supported.

For Gigabit Ethernet adapters, i.e., those controlled by gelan or igelan, the MTU can only be set to 1500 or 9000. Other values are not supported."

=> check your adapter type using lanscan -v and look at "Driver Specific Information"
$ lanscan -v
-------------------------------------------------------------------------------
Hardware Station Crd Hdw Net-Interface NM MAC HP-DLPI DLPI
Path Address In# State NamePPA ID Type Support Mjr#
0/0/0/0 0x00306E06C628 0 UP lan0 snap0 1 ETHER Yes 119

Extended Station LLC Encapsulation
Address Methods
0x00306E06C628 IEEE HPEXTIEEE SNAP ETHER NOVELL

Driver Specific Information
btlan

[Khalil Ahmed]

Hi Prashant,

I'm not a networking expert so your second paragraph went straight over my head!

The commands I ran were taken from information I found on the NET when searching for how to set the MTU size on HP-UX.

If possible please provide commands that I can run.

Thanks

Khalil

[Antonio Cardoso_1]

not sure my response was advertised (network error),
look above.

[Khalil Ahmed]

Hi Antonio,

We have gigabit cards, I did a lanscan -v and I've attached output... for extra information to anyone if it helps.

Khalil

[Antonio Cardoso_1]

Khalil,
according to
http://docs.hp.com/en/J5683-90017/index.html
=> see §3 Administration,
Gigabit-Specific Information
Table 3-1. Allowable MTU Sizes

it seems that 1500 is the minimum.

[Khalil Ahmed]

Hi Antonio,

I have had a look at the Admin document and specifically the allowable MTU sizes.

We have an HP 1000Base-T Dual-port lan card using the iether driver. The table says the MTU range for this card is 1024 to 9000.

Thats very bad news for us, we need to set the MTU size to 500 because we are implementing a Mobile Service system that requires the MTU size on the server to be set to 500.

I have raised a call with HP and asked them to look at this issue as we must be able to set the MTU size to 500.

If anyone knows how this could be got round (ie how we can get the MTU size to be 500) please let me know.

Regards

Khalil