Optional Step: Configure Jumbo Frames Size (Jumbo frames are supported only at 1000 Mbit/s)

Jumbo frames for the iether driver on HP-UX 11i v 1.0 and on11i v 2.0 of September 2004 (or later) have an mtu_size in the range from 1501 to 9000 bytes.
If you are using Jumbo Ethernet frames, ensure that:
- all end stations on a given LAN^[3] have the same maximum transmission unit (MTU) setting;
- intermediate stations such as switch ports in your LAN have an MTU equal to or greater than the end station’s MTU.
Obtain the PPA number of the card by entering lanscan.
Choose one of two configuration methods that will permanently save your configuration.
- use the GUI-based system admin manager (SAM).
  To use SAM, type sam at the HP-UX system prompt; then double-click Networking and Communications, and then Advanced Configuration--see Ethernet Support Guide for details, and then do the steps for verifying the MTU size;
  or
  edit the following configuration file using an editor such as “vi”:
  /etc/rc.config.d/hpietherconf.
  Set the mtusize by editing HP_IETHER_MTU[0]=mtusize, and insert the proper interface name: HP_IETHER_MTU[i]=HP_IETHER_INTERFACE_NAME. When the system reboots, the interface will be configured for jumbo frame operation.
Verify MTU change by entering netstat -rn. If MTU has not changed, enter the following commands:

$ifconfig lan PPA_number unplumb
$ifconfig lan PPA_number ip_address netmask netmask up
To check (or verify) the current Ethernet frame size, enter:

$lanadmin -m PPA_number

An alternative way to temporarily configure jumbo frame size is to enter:
lanadmin -M mtu_size PPA_number.

Using lanadmin is temporary because it will not preserve your settings across reboots.

The PPA_number is the one we obtained from the output of lanscan. For using Jumbo Frames with the iether Gigabit Ethernet driver on HP-UX 11i v 1.0 or 11i v 2.0 of September 2004 (or later), set the mtu_size to a number from 1501 to 9000 (bytes).

^[3]In the Jumbo Frames discussion, “LAN” means that the end stations do not have any routers or layer 3 switches in between them.

Optional Step: Configure Jumbo Frames Size (Jumbo frames are supported only at 1000 Mbit/s)

Technical documentation

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