[c-nsp] Long range 10G ethernet?

[Peter Rathlev]

(On 6500/Sup720 and with LAN cards)

We're currently using a gigabit link with a total loss of 24.1dB (at
1510 nm) from end to end. We're using some third party "120 Km"
transceivers, and this is working well.

Now we're thinking about making it a 10G link instead. Finding 10G
transceivers capable of supporting at least ~24-25dB seems tricky
though. Googling a bit reveals something like the Optospan
SPP-81D-K080T31, rated for 25dB at 1310nm. Of course we're primarily
using X2 transceivers, and that one is an SFP+.

Questions:

1) Any general ideas about how to best run 10G on 25+dB stretch without
external amplification? We'd like to avoid the extra complexity that
would introduce.

2) We might cut ~1dB by splicing in a few places instead of patching,
but we probably can't get below 23dB loss. Would using 25dB capable
transceivers on a 23dB stretch be too bold for comfort?

3) Does the OneX converter support any SFP+? Or is it somehow locked to
only support certain modules? Cisco[1] mentions only CU, SR and LR as
supported. Any (electrical) reasons OneX couldn't support any kind of
SFP+? Should we count on being able to use e.g. the aforementioned
SPP-81D-K080T31 in a OneX in e.g. a 6708 or Sup2T port?

[1]: http://www.cisco.com/en/US/prod/collateral/modules/ps5455/data_sheet_c78-547521.html

-- 
Peter