[c-nsp] DOM on 6724-SFP (was: Will UDLD work with converters ?)

[Marian Ďurkovič]

On Sat, Oct 03, 2009 at 08:12:47PM -0700, Kevin Graham wrote:
> > Also, bear in mind that not all c65k ports support reading DDM info from SFPs.  
> 
> > SUP720 cards will, as will later hardware revisions of the 6724sfp blades.  
> > Earlier hardware revisions won't.
> 
> Yeah. I really wish this had gone under a new part number (WS-X6724A-SFP?).
> It hasn't happened yet, but I dread having to RMA one of our HW rev >= 3.0
> cards.

Well, DOM on 6724-SFP is one of the "policy-banned" features I'm afraid.

For many years, multiple customers tried several times to get it working.
This topic was also mentioned on various meetings with Cisco, for example
in 2007 I gave the following presentation on European NREN workshop:

http://md.bts.sk/wien2007-dom.pdf

In 2008, the broken I2C bus was fixed on 6724-SFP linecards (HW rev 3.0)
and everyone hoped the problem is over. But instead of announcing DOM
support on these cards, new IOS "enhancements" were put into SXI train,
which aim to disable this functionality in software:

#sh inte g 3/1 tra
Module 3 doesn't support DOM
 
#sh inte tra supported-modules
Mod  DOM support
---- --------------
  3  Not Applicable

I really fail to undestand, why someone at Cisco tries to make our work
harder and disables highly useful features for no reason. I suppose it's
just a belief that customers will buy ES20 modules instead, but given
that wirespeed 1RU switches with 10G uplinks and 24 SFP downlinks are
available from multiple vendors at reasonable prices, this assumption
fails miserably.
 

     With kind regards,


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