X-Mozilla-Status: 0001
        X-Mozilla-Status2: 00000000
               Message-ID: <36203774.F6C24D36@concentric.net>
                     Date: Sun, 11 Oct 1998 00:43:32 -0400
                     From: Eric Durant <eadurant@concentric.net>
                 X-Mailer: Mozilla 4.5b2 [en] (WinNT; I)
        X-Accept-Language: en
             MIME-Version: 1.0
               Newsgroups: execpc.general
                       To: Steve Mading <madings@earth.execpc.com>
                  Subject: Re: ISDN Question
               References: <6vj4b3$ncj@newsops.execpc.com>
                           <6vja7v$982@newsops.execpc.com>
                           <6vk14o$hp6@newsops.execpc.com>
                           <6vlp98$69d@newsops.execpc.com>
             Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

Steve Mading wrote:
>Andy (mcmahan@execpc.com) wrote:
>:Let me ask another question then...How do I know for certain that I'm
>:using both channels?  I've not noticed ANY difference between when I'm
>:using my phone while connected and when I'm not -- but Motorola
>:assures me that I have everything set up properly and initialized
>:properly to use both channels....

>FTP something large.  Measure the difference between doing it with one
>line and with two.  Try at several different times and average them
>because factors other than your own ISDN connection can affect the
>test.

One of the major factors is compressibility of the data.  This can be
controlled somewhat by testing with a random data stream, which can be
"approximated" by a highly (e.g. maximal zip) compressed or encrypted
file.

Another factor is the network bottlenecks between you and the FTP site. 
FTPing to your ExecPC shell account is the best control I can think of
for this.

Also, keep in mind that if you're using an external TA the speed of your
serial port is a factor.  When I tested the BitSurfr Pro bonded last
year on a WinNT PC with the serial port at 115.2kbps, I got about 90kbps
of data.  I don't know if this is near optimal given the coding
efficiency, but it's one point to compare to.

One the same system on a single B channel, I got data throughput within
0.5kbps under the 64kbps data channel capacity.

Veering slightly off topic, from January through September my
Greenfield, WI ISDN line would not support data on the 2nd B channel. 
Ameritech was unable to resolve the problem after three service
incidents, although they thought it may be related to my ISDN line being
"virtual".  (I'm not sure exactly what this means, but I think it has to
do with a limitation of the Ameritech system in Greenfield.)  The weird
thing is, I was able to bond fine until last December.  I finally
discontinued the service out of frustration.

Eric Durant
---
Website:  http://www.edurant.com/
ICQ:      9118339