Hello:
I am very familiar with multiplexing digital services at the
copper-speeds (DS3/DS1). My question has to do with the similarities
and differences at the optical-speeds (OC-3/OC-12).
For example, when you have a multiplexed DS3, it has 28 individual
DS1 channels. However, the OC-X speeds don?t seem to evenly divide
into DS-X speeds, but from what I understand, most of the time OC-X
spans are broken down into DS-X spans -- so why not make the speeds an
even multiple?
Are OC-3s usually broken down into DS3s and then into DS1s (if
needed), or are they directly broken down from the OC-3 level to the
DS1 level? If the latter is true, then can a combination exist on the
same OC-3 (some channels are broken down into DS1 and some into DS3)?
It seems like such a setup would complicate the situation quite a bit.
Also, are the individual DS1 or DS3 spans within an OC-3 called
?channels?, as they are in the case of DS1 spans in a DS3? Would you
have, for example, three DS3 channels in your OC-3 with 28 DS1
channels in each of those? Would that mean to identify a particular
DS0 in your OC-3 you?d need to address it as OC-3 Channel XX, YY, ZZ
where XX is the DS3 channel within the OC-3, YY is the DS1 channel
within the DS3 and ZZ is the actual DS0 channel within the DS1?
Lastly, if you?re asking a carrier to provision services on your
OC-3, how do you specify which part of the OC-3 you want / how does a
CFA for a ?channel? on an OC-3 look?
Does the term ?STS-1? play a role in any this? From what I can tell
an OC-3 is three STS-1s? that?s probably the start to my answer.
Again, most importantly is how all of this comes back down to the DS1
level? and all the terms involved.
Thanks for your help. |
