[c-nsp] DWDM Optics use

[Keegan Holley]

No this is exactly what I was looking for.  I can definitely understand the
usefulness of having your routers transmit on a specific channel.  Thanks!

2011/6/4 Brandon Applegate <brandon at burn.net>

> On Sat, 4 Jun 2011, Keegan Holley wrote:
>
>  I'm struggling with a use for DWDM optics.  I understand the concept of
>> DWDM/CWDM and phase shifting to create more links over a single fiber.
>>  Once
>> that is done the ASIC/FPGA bandwidth allocated to the port remains the
>> same,
>> correct?  So if I create multiple 1G connections on a single port with
>> these
>> magic sfp's am I still limited by the 1g/2g chip in the device.  Are all
>> the
>> logical connections forced to be sub-rate?  I know the larger equipment
>> handles this differently, so I'm only concerned with the 3750/3560 size
>> boxes.
>>
>>
> Hmm, I may be misunderstanding - but I think you are misunderstanding how
> DWDM tuned optics works.  A 1g or 10g DWDM optic is still a singe 1 or 10
> interface.  It's just that that transmit laser is tuned to a channel (i.e.
> 1546.12).
>
> Router#sh int tenGigabitEthernet 7/1 | inc media
>  Full-duplex, 10Gb/s, media type is DWDM-46.12
>
> The reason you may need this is to connect this port directly to a (R)OADM.
>  There are (at least) two ways on the DWDM transport side to handle this:
>
> a) Use a *sponder (transponder = 1:1, muxponder = n:1, etc).  You can use
> 'grey' optics now (i.e. good ole SX/LX etc).  These cards on the DWDM side
> are expensive though.
>
> or
>
> b) Buy DWDM optics, and go directly into the mux/demux on the DWDM.
>
> We are doing option b) in parts of our network because the cost of a) was
> too much, and these links aren't going to do any moving around or going away
> any time soon.
>
> Again, apologies if I've misunderstood you.
>
> --
> Brandon Applegate - CCIE 10273
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