Subject: Re: Clock synchronization with ISDN
To: Jan-Hinrich Fessel <>
From: Jonathan Stone <jonathan@DSG.Stanford.EDU>
List: tech-kern
Date: 02/18/1997 00:03:19
>In message <>you write:
>> On Mon, 17 Feb 1997 11:53:59 -0800, Jonathan Stone  
>> Most of the timestamps present in ISDN are generated by the last switch  
>> before your end of the BRI or PRI, therefore latency will be reasonably low  
>> (not more than your ISDN link itself (round-trip times of no more than 2-3ms  
>> worst case).

Please be careful with the attribution. I did *not* write the above,
and it could be *profoundly* embarrasing, professionally,  if  someone
were to gain the impression I did.  Could you correct the attribution, please?

[snip observation that not all switches use DCF-77 for timestamps]

>I have heard of switches that are DCF-syncronized, but you can't count on this.
>I have noticed the timestamps are more behind real time when they come near to 
>"no B-Channels availible" messages, It looks like the switch in question 
>looses clock ticks when under heavy load.

Heh, that sounds much closer to reality than the mis-attributed quote above.
(Cute, too.)