[e2e] seeking help recalling a network term

weigengyu weigengyu at hotmail.com
Thu Jun 15 20:10:38 PDT 2006

to make things clear:

1. The telephone networks including fixed or mobile ones are circuit-switching.
2. There is only SS7 used for control message transmission, SS7 networks is a packet switched networks.
3. Some future services like IMS need connection setup stage before communication. 
That will be on an IP based packet switching network.
4. The quality of services requires limited delay of setup connection.  There is no guarantte by TCP or SCTP. 
You have to wait long time when you start to establish a connection in current Internet. 


----- Original Message ----- 
From: "Ted Faber" <faber at ISI.EDU>
To: "weigengyu" <weigengyu at hotmail.com>
Cc: "Jon Crowcroft" <Jon.Crowcroft at cl.cam.ac.uk>; <end2end-interest at postel.org>
Sent: Thursday, June 15, 2006 11:30 PM
Subject: Re: [e2e] seeking help recalling a network term

On Thu, Jun 15, 2006 at 11:47:33AM +0800, weigengyu wrote:
> There is a set of signal lamps every 2km to control railway train go/stop here.
> In telecom, SS7 networks are packet switched networks,
> The SS7 messages/packets are actually controlled link-by-link  in operations.
> The mechanism to prevent congestion is to keep the traffic less than 0.7 Erlang for each link.
> Telephone networks works well in general.

Yeah, for circuit-switched fixed-capacity voice calls. :-)

There's more than one way to do most things, congestion control
included, and the problem you want to solve should guide your approach.

Ted Faber
http://www.isi.edu/~faber           PGP: http://www.isi.edu/~faber/pubkeys.asc
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