[nsp] OC3 interfaces for 7xxx vs. other OC12 transport options

[Neil J. McRae]

> ds0s are not part of sdh tho, the docs say it can go down to 
> E1s and do channelized E1s, this implies to me a kind of 2 
> stage muxing is occuring, the first bit being SDH, the second 
> being G704 


Correct, we use these cards here at COLT:

Great interface names ! :-)

Serial5/0/0.1/1/3/1:0 is up, line protocol is up 
  Hardware is Channelized STM-1
  Description: XXX
  ....
  
controller SONET 5/0/0
 framing sdh
 !
 au-4 1 tug-3 1
  tug-2 1 e1 1 channel-group 0 timeslots 1-31
  tug-2 1 e1 1 clock source internal
...
  tug-2 3 e1 1 channel-group 0 timeslots 26
  tug-2 3 e1 1 channel-group 1 timeslots 27
  tug-2 3 e1 1 channel-group 2 timeslots 25
  tug-2 3 e1 1 channel-group 3 timeslots 24
  tug-2 3 e1 1 channel-group 4 timeslots 30
  tug-2 3 e1 1 channel-group 6 timeslots 31
  tug-2 3 e1 1 channel-group 7 timeslots 17
  tug-2 3 e1 1 channel-group 8 timeslots 20-23
  tug-2 3 e1 1 channel-group 9 timeslots 28


They are very useful for delivering a huge number
of DS0/E1's 

The OC12 version is very good for DS-3's also:

controller SONET 6/1
 framing sdh
 aug mapping au-4
 au-4 1 vc-3 1 serial e3
 au-4 1 vc-3 2 serial t3
 au-4 1 vc-3 3 serial t3
 au-4 2 vc-3 1 serial t3
 au-4 2 vc-3 2 serial t3
 au-4 2 vc-3 3 serial t3

Problem with it is that a fully loaded box could have +thousands+ of
customers on it and if it reboots your helpdesk will be busy. 

Be wary and test these with the mux/DXC that you plan to use as there are
subtle
differences in the way that each mux talks.

Regards,
Neil.