Subject: Re: Clock synchronization with ISDN
To: Ted Lemon <>
From: Christian Kuhtz <>
List: tech-kern
Date: 02/17/1997 19:26:02
On Mon, 17 Feb 1997 12:42:54 -0800, Ted Lemon <> wrote:
> > Isn't ISDN signalling *slow*?  If it's slow, then how much jitter is
> > that, and (at best) discretisation at the 9600-baud D channel line speed
> > adding?  Not  to mention  switching delays inside the telecom net?
> Furthermore, aren't the 2B and the D channel really multiplexed over a
> single serial channel?

That depends on how you look at it, since there are a variety of different  
perspectives possible; as you possibly are aware of, ISDN is a fairly complex  

For our purposes, no, they're not multiplexed in such a way that one takes  
priority over the other and can force traffic to be delayed based on traffic  
on the other two B channels in case of a BRI.  The latency for 16Kbit/s D  
channel traffic is constant latency, no matter what happens with the two  
64Kbit/s B channels.  Even if they end up going through the same pipe.

Christian Kuhtz <> (work),   <> (personal)
UNIX/Network Specialist,   "A German in the U.S., speaking for himself *gasp*"
Paranet, Inc. Rocky Mountain Branch,  MIME/NeXTmail Ok