[c-nsp] ONSs, DWDM SFPs, and the 3560/3750E

[Michael K. Smith - Adhost]

Hello Justin:

I am responding to your original post after reading your comments about owning the fiber.  My comments are in line below.

> So I'm working on a solution involving a pair of 15454s to transport
> numerous GigE links between a pair of sites over diverse paths and
> still
> give us a 10G upgrade path someday.  Unfortunately I know little about
> the ONSs at this time even though I've been staring at data sheets,
> presentations and the Dynamic Config Tool for weeks if not months.
> Like
> where do I use the filters?
> 
The filters are put in place between your 15454 and your one-pair uplink.  So, something like this:

15454 -> Lambda 1  \
	-> Lambda 2   -> Filter (muxes wavelengths) -> outbound fiber
	-> Lambda 3  /

And then same in reverse.  So if you have 3 Lambdas, you will have 3 fiber connections into the filter from 15454 on separate wavelengths and the output will be on one set of fibers for transport.

<snip>
> http://www.cisco.com/en/US/prod/collateral/optical/ps5724/ps2006/produc
> t_data_sheet0900aecd805ebef7.html

<snip>

> I've been told that the Xponder card can only accept GigE fiber inputs
> using the DWDM SFPs and that we'll have to convert to DWDM optics with
> an external switch if we have to use copper or other fiber links.  Is
> this true?  The one page I found on the Xponder card contradicts what
> this person is telling me.  I haven't had any luck finding good design
> or implementation docs on this card or exactly how it's used.  Both of
> our upstreams hand off as copper.  Fiber is not an option with one of
> the upstreams and with the other it's not something that we've
> discussed.  Either way it wouldn't be with DWDM optics.  The current
> data center hardware can only accept copper, for now.  Our internal
> connections can be fiber.
> 
I didn't read it that way.  Here's the quote I'm referring to that indicates you can plug basically anything into it on the distribution side.

"The 20 client ports can be equipped with different Gigabit Ethernet SFPs: SX, LX, ZX, coarse wavelength-division multiplexing (CWDM), DWDM, or electrical (RJ45). Figure 2 shows a Layer 2 logical scheme, and Figure 3 shows a Layer 1 physical scheme."

<snip>

I would get some Cisco pre-sales support for your design, particularly since it sounds like you're a little thin on the optical engineering side.  There are other considerations that they can help with (do you need the filters, loss budget calculations, amplifiers, etc.).  I have found their optical teams are pretty good and, if you tell them exactly what you're trying to do they should be able to come up with a design for you.

If you don't have it already, you should have good OTDR data on your fiber runs because there are different optics that you will use depending on how far (from a db-loss perspective) you have to go on the two shots.

Regards,

Mike 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: PGP.sig
Type: application/pgp-signature
Size: 475 bytes
Desc: not available
Url : https://puck.nether.net/pipermail/cisco-nsp/attachments/20080407/4aa28cdb/attachment.bin