[nsp] Cat 6500 jumbo frame support anomolies

[Keoseyan, Scott]

Turns out there was a bug in the driver for the 1000Base-T NIC in the server that was causing it to send frames over the 9216 byte limit when jumbo-frame support was activated on the NIC.

-sak


> -----Original Message-----
> From: crockers at mail.trinicom.com [mailto:crockers at mail.trinicom.com]
> Sent: Wednesday, April 09, 2003 2:56 PM
> To: cisco-nsp at puck.nether.net; Keoseyan, Scott
> Subject: Re: [nsp] Cat 6500 jumbo frame support anomolies
> 
> 
> Scott,
> 
> Send sh mod, sh port jum, and verify that you have the right mtu
> configured on the MSFC's VLAN interfaces.
> 
> I'm not sure about 6316s, but 6416s and 6516s work fine...
> 
> Sean
> 
> ---------- Original Message ----------------------------------
> From: "Keoseyan, Scott" <Scott.Keoseyan at Broadwing.com>
> Date:  Wed, 9 Apr 2003 09:41:25 -0400
> 
> >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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