Dial-in access

Kent W. England kwe at geo.net
Wed Aug 13 17:50:37 UTC 1997

At 12:12 PM 13-08-97 +-200, Jan Novak wrote:
>Do somebody of you use some kind of this rerouting or DXCs bypass and with
which devices or is this functionality included directly in the voice
switch ???
>Only pointers to vendors are quite sufficient - Nortel´s  "Internet
Thruway" can be a example.

If you are dealing with an existing voice switch, I don't think you have
much choice but to handle it with that voice switch vendor's product. Third
party solutions seem to have too much to do with handling call recognition
to be cost effective. Both Nortel and Lucent have announced plans to deal
with data calls by off-loading from the first voice switch onto a packet
network. Frankly, I don't understand enough about voice switch architecture
to know how well that deals with first-switch overloading, but it will
certainly deal well with the inter-office trunk overloading that is
prevalent in the US architecture.

Another idea that you should seriously consider is "always on ISDN". The
concept is to use all three BRI ISDN channels as a dedicated link to a
single ISP. It may be possible to set things up in the voice switch to
allow more than one ISP to play in this game, but the idea is to use the D
signaling channel as a dedicated low speed link between the premise and the
selected ISP. The two B channels are brought on as data is presented for

The idea is to make the circuit switching happen on the time scale of
Internet connection association (ie, TCP setup and teardown). This gives
the data user the same or better call characteristics as the voice caller,
thereby easing the load on the switch and allowing it to multiplex more
efficiently than it does when the data circuits stay nailed up almost

I would suggest that you talk to your switch vendors about how to implement
"always on ISDN" on their switches and then think carefully about how to
price this service. (In other words, you had better not keep the same
pricing as current per-call tariffs, but come up with either a flat rate or
a usage based on traffic measure so that users don't have to worry about
the cost of thousands of calls per month.) You can compare this to the
front-end offloading approach and pick the one that seems most cost
effective and scalable. In fact, why not do both? If Czechoslovakian phone
companies aren't totally focused on preserving a monopoly of obsolescent
phone services as here in the US, then perhaps innovative circuit switched
data services are feasible? If not, you could always swim uphill with xDSL
or cable modems. :-)

Hope this helps.


Kent W. England                                     Direct: 650.596.6321
VP of Technology                                   Company: 650.596.1700
GeoNet Communications, Inc.                            Fax: 650.596.1701
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