Subject: Re: Clock synchronization with ISDN
To: Jonathan Stone <jonathan@DSG.Stanford.EDU>
From: Stephen Ma <>
List: tech-kern
Date: 02/18/1997 10:03:22
>>>>> "Jonathan" == Jonathan Stone <jonathan@DSG.Stanford.EDU> writes:

Jonathan> Isn't ISDN signalling *slow*?  If it's slow, then how much
Jonathan> jitter is that, and (at best) discretisation at the
Jonathan> 9600-baud D channel line speed adding?  Not to mention
Jonathan> switching delays inside the telecom net?

The ISDN D channel is 16kbit/s, not 9600bit/s. Also, there is (or at
least should be) no switching delay: ISDN signalling messages are
generated inside the local exchange. The only delay should be queueing
delay on the D channel itself (which shouldn't happen unless you're
running X.25 over the D channel, or have a ridiculously high call
rate), and packet xmission delay. All of these delays should be
reasonably constant.

- S