SUMMARY: Can't set MTU higher than 1500 on Sun GigE cards

From: Gilbreath, Jeff <>
Date: Thu May 16 2002 - 16:47:40 EDT
Thanks to all the people who responded.

Quick Overview:
Private switched but non-routed network with Cisco Catalyst switch and all GigE blades in switch.
Various Sun servers with GigE cards connected to private network.
GigE to GigE, so fragmentation is not a issue.
Testing done through switch as well as direct server to server.

I can't turn the MTU size up on the GigE interface to increase throughput.

Official answer finally recieved from Sun is the Sun GigE cards no longer support Jumbo packets.
And can not be set to a MTU higher than 1500 (same as 10BaseT/100BaseT).

Sun GigE cards max out at about 440Mbits transfer rate even running multiple treaded iperf and ttcp tests.

My response:
Thanks to the people who suggested using SysKonnect and Intraserver cards as a alternative
to the Sun cards. They seem to be higher performance and cheaper too.

Note: The Tolly report thats listed on Sun's web page must be using the previous version.
sunmanagers mailing list
Received on Thu May 16 16:52:23 2002

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