Re: Low latency IP direct connection over ISDN

On 2012-11-14 12:33, "Schürer IT Beratung -- Urs J. Schürer" wrote:
> 
>>> But even if the call takes the long way, the latency will be MUCH
>>> lower.
>>
>> Why (I'm not really familiar with how current telecommunication
>> networks are built; you read contradicting things about this on the
>> internet) shouldn't ISDN and IP be transferred over the same lines?
>>
> No. They only share the copper cable for a very short distance.
> 
> IP (xDSL) is only between your APL (Splitter/DSL-Modem) and the DSLAM
> which is usualy located in the next Vermittlungsstelle or even nearer in
> those big new outdoor DSLAMs. After that it is decoupled and runs via
> its own IP network.
> 
> ISDN runs via classic telco connections directly from Vermittlungsstelle
> to Vermittlungsstelle or so.
> 
> So you have two completely independet networks.

I'm not sure about this. At least in “Anhang A zum IP-BSA 2010-Vertrag”
[1], it is stated that the DSL traffic can be provided via SDH, so I
suppose that all signals are multiplexed over a single (optical) line
between the exchanges.

I don't know if we should continue the discussion/our speculations on
the list. At least I have no real or first-hand knowledge about any
bigger telecommunication networks or other networks that aren't Ethernet
and copper based and thus have nothing substantial to add.

> Have a look at that recent c't article describing Telekom's move to an
> all-IP network
> (http://www.heise.de/ct/artikel/Der-stille-Machtkampf-973310.html).

Sounds scary. Hopefully this fails similar to ATM (reading old ATM books
is always entertaining).

Regards,
Matthias-Christian

[1]
http://www.wholesale-telekom.de/produkte-pstn/vorleistungen-fuer-isp/ip-bitstromzugang/