[c-nsp] Cheap 10G between 7600 and Procurve 5406zl

[Lincoln Dale]

On 18/03/2010, at 9:10 AM, Nick Hilliard wrote:

> On 17/03/2010 21:28, Lincoln Dale wrote:
>> this assertion is also false.  i can categorically state that there
>> has not been, there have been any number of quirks with "standards
>> compliant" MSA transceivers.
> 
> To be fair, Lincoln, Marian is talking about a different level of incompatibility going on here.  There are quirks in all hardware interfaces (the free unix ethernet and SCSI drivers make interesting reading), but getting good compatibility between 10G chipsets and arbitrary SFP+ transceivers is going to be a whole lot more difficult than writing a driver to take into account that SFP+ model X does action Y in circumstance Z.  Analog to digital conversion is a black art.

for mainstream stuff - e.g. SR, LR etc. - there should be no issue.
the devil is in the details of which getting into the gory technical details probably isn't relevant here, but suffice to say that for SR/LR i have not seen any interop issues but the more esoteric stuff (CX1, LRM) have.

> 
>> in either case the EDC issue to what i talked about is really only
>> specific to LRM and Passive CX1 on SFP+. SR/LR are just fine.
> 
> I had been planning a small short-reach (800m) CWDM deployment using SFP+ optics.  What you say comes as rather bad news.

Cisco at this point in time does not ship any CWDM 10G transceivers - in any form factor - AFAIK
google says that they are available.

as stated earlier today, Cisco does not preclude you from using 3rd party transceivers.
if you so wish to do so you may well find that function flawlessly.  you might find they burst into flames.  whatever the outcome, you're assuming the risks by enabling and inserting a 3rd party transceiver.


> 
>> what is used behind the scenes (XAUI, XFI) has no bearing on you as
>> an end customer AFAIK - beyond whether something is available or
>> not.
> 
> It's not particularly the transceiver MII which is the problem here, it's the form factor / end product.  XFP already delivers a good variety of optical interfaces, while X2 doesn't really come close in terms of range or suppliers.  This means that if you need an exotic X2, both purchase and support/replacement lead times are going to be bad.  This isn't a huge problem if you're a large customer buying lots of kit, but if you're a small customer, it's incredibly expensive to ask your local Cisco partner to keep 10 different types of DWDM X2s in stock as spares.

reality is that Cisco will fail if we continue to not meet your requirements - straight open market dynamics.

if its a showstopper that Cisco does not ship XFP on a given platform then thats the feedback you need to give to your cisco account manager or partner team, and request that they feed it back to those that make these decisions.

as much as i like a good conspiracy theory as much as the next guy, on X2 vs XFP i know of no conspiracy, simply timing of what came out when and then feedback from many customers on wanting to re-use existing (X2) transceivers they already have.


cheers,

lincoln.