The IP Over NBMA (ION) Archive

["Feiling Jia" <jia@portal.optivision.com>]

Hi, all,

As a new comer to ION mailing list, it is quite entertaining to watch intense
discussions on ADSL deployment. I happened to learn something about ADSL
deployment (after spending some time working at PacBell) and would like to
share with you my opinions.

Regarding Jed's question, the picture is all right except that a voice/data
splitter inside DSLAM should generate another output going to the POTS switch.
I heard that some DSLAM vendors will provide an ATM interface card which can
be used to connect to an ATM network (switch). You can also connect DSLAM data
outputs directly to an IP router if the Telco is providing IP routing services
and you are stucked with one IP provider.
A NAP usually consists of one or more ATM switches to which many ISPs are
connected. Therefore, connecting outputs of DSLAM to ATM switch allows
end-users to choose their ISPs. 

Your comments are welcome.

Feiling Jia
Optivision, Inc.
3450 Hillview
Palo Alto, CA 94304

Tel. 415-855-0217
Fax. 415-855-1771
Email: jia@optivision.com



--------------------------------------
Date: 4/22/97 11:32 AM
To: Feiling Jia
From: James E. [Jed] Donnelley
Rajeev Kochhar <rxk@3com.com> wrote:

>Many companies are building devices called DSLAMs. You can consider these
>as modem banks for xDSL technology.

A useful document I found on:

Digital Subscriber Line Access Multiplexer (DSLAM)

is:

http://www.adsl.com/adsl/private/snag_wt.html#5.2

in the ADSL Service Network Architecture Group (SNAG)
documentation.

The figure that is at that anchored URL shows a variety
of local loop transport technologies bringing data
into the DSLAM, and then the data going out through
an ATM switch (or visa versa naturally).  I am a bit
surprised by this use of ATM.  Can somebody explain
to me what ATM adds to this mix?

In the approach I discussed before coming out of the
DSLAM (or something like it) would be a connection to
an IP router for feeding upstream and a POTS connection
into the existing POTS switched network.  What is wrong
with that picture?




Jed Donnelley    jed@llnl.gov   Phone: (510) 422-4309
http://www.webstart.com/jed/    FAX: (510) 423-1355