[nsp] Cat 6500 jumbo frame support anomolies

[Tom Holbrook]

Scott-

Is the connection 100 Mb? The WS-X6516-GE-TX uses an Application Specific 
Integrated Circuit that limits it to an MTU size of 8092 bytes at 100 Mb. 
At 10/1000 Mbps, up to 9216 bytes can be supported.

-Tom


At 09:41 AM 4/9/2003 -0400, Keoseyan, Scott wrote:
>Hello,
>
>I have enabled jumbo frame support on a 6500 (CatOS 7.2.2 with 
>WS-X6316-GE-TX) and then on a couple Netfinity X-series servers 
>w/1000Base-T NICs and I am seeing some strangeness.
>
>Performance seems sluggish between these two devices and the two 
>interfaces on the switch are recording giants.  I checked the IBM docs for 
>the NIC and they state either that the frame-size is 9000 bytes or 9KB 
>(9216 bytes) (they were unclear) which should be fine as the jumbo-frame 
>size on the switch is 9216 bytes.  I don't have the server NICs configured 
>for anything special other than I have the secondary NIC configured as a 
>stand-by port connected to another switch, and I am wondering why I would 
>still be seeing giants and why the performance is off.
>
>Would anyone have any ideas?  I have disabled jumbo-frame support on the 
>switches and the servers for the time being but I am concerned that having 
>it turned on would be a problem.
>
>-sak
>
>
>
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__________________
Tom Holbrook
Sr. Network Engineer
Earthlink - Atlanta

'Safe?' said Mr. Beaver...'Who said anything about safe? 'Course he isn't 
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--The Lion, the Witch and the Wardrobe