[c-nsp] Sonet "hard" patterns for testing

[Bill Wichers]

The problem data strings are usually either strings that match control
codes or long sequences of either all ones or all zeroes. If too many
bits go by without any transitions it is possible for the receiver to
loose sync with the network. You might want to just try a packet of all
zeroes or ones as an experiment.

You might try looking up one of the earlier documents detailing the
SONET specification. There used to be a lot more concern for timing and
jitter and the like than there is now, which I think is due to better
time bases in modern gear making many of those issues less of a problem.


I'd try looking for things like "jitter" and "clocking" in your search.
While those might not key in on what you're looking for directly,
they're likely to find you information that also includes some of what
you're looking for.

   -Bill


> I just got bit by a problem with scrambling not being on on a POS OC3
> with a upstream provider... (Long story - provisioning person at
> provider had no clue... insisted that it wasn't needed).   Symptom of
> course was certain files just not being able to be transfered past a
> certain point - where the file contained patterns not possible to
> transmit across a non-scrambled POS circuit.   Took me a while to find
> it, though, because normal ping packets of course go through just
fine,
> 100% of the time.
> 
> In testing this, though, I would have loved to have some payloads for
> ping packets which weren't sendable on a non-scrambled POS circuit..
and
> probably other underlying circuits also.   Sort of a set of
"difficult"
> packets to try to send.
> 
> Google has not been my friend in this regard... probably not using the
> right keywords, if the data exists out there at all.
> 
> Ideas?
> 
> -forrest