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DS-3 CESM question - [summary]

  • From: Alex Bligh
  • Date: Tue Jun 22 16:18:55 1999

Several people kindly responded to my
plea for help on getting a DS-3
to work between two cisco PA-2-T3
cards, where the carrier chose to
provide this over a CESM interface.

Just in case anyone else has to suffer this, here's
the useful data I found. The framing (i.e.
low level DS-3 framing - *NOT* ATM cell framing)
which as I understand it is pretty much the line
encoding, operates between the your CPE and
the CESM interface at each end. Thus, unlike
a "raw" T3, the carrier has to be aware of
your line coding.

Other than that, they are identical.

And for the puzzled - at one end there was a miswire
between our router and the telco DDF. Our TX was
correctly connected, but our RX was connected to
an arbitrary other port with a different type
of framing selected on the CESM card. Hence
we saw LOF. And the loop tests we asked from 5000
miles away to be applied, were, um, not
performed entirely compatibly with scientific method.

And yes, it does seem to work (or at least
has done for a few hours).

Thanks once again for everyone's help.

Alex Bligh
GX Networks (formerly Xara Networks)