Ascend Archive
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Re: (ASCEND) Am I the only one ??

On Mon, 28 Sep 1998 11:06:33 -0300, Ricardo Freire wrote:

>De: Morten Norman <marten.norman@intertex.se>
>
>>The standard indeed says 33600, just like it says 56000 in the other
>>direction.  But on real lines it's often reduced to 31200 or 28800.
>>
>>Reason?  To reduce interference to the downstream. (Data goes in two
>>directions on the same "copper wire", remember?)  Most echo and
>>interference can be compensated, but sadly enough not 100%.

I wont buy this explanation yet (1).

>>Forcing 33600 upstream may reduce downstream speed instead, and
>>probably more than gained in upstream.  Thus I guess it's a fair
>>tradeoff.
>
>
>Ok, I can accept it, even if virtually ALL V.34 connections go 33.600 in
>BOTH directions... (maybe we're inheriting US FCC limits to 56K, so we
>cannot get 33.6K?)

I don't buy this either (2) !!

>But... why shouldn't none of our MAXes connect at 31200 upstream? As i've
>said, it NEVER happened. It's always 28.8K. I think it could at least *TRY*
>to do it... It looks like a fixed upper limit. I don't understand it. As I
>don't understand the silence of our Ascend friends...

I wouldn't go knocking Ascend on this yet, I am sure either Matt or
Kevin will come back with a sensible reply given time. Its not only
Ascend btw, I have spoken to people running cisco, pm's & usr and
they dont ever remember seeing anything higher than 28800 on their
back channels either.

Now I don't want to get into the hard technicalities (and I dont
fully understand them :-) but I am sure there is a good reason for it
which will make sense in the long run, I really would like to see
MegaZone's comments on the matter  if he makes any :-)

He in Australia we use E1's not T1's but I don't think that really
has any bearing, we are now seeing from a number of users 54000 (or
53999 i think) and some very consistant 56000 connects. I can
actually map those users to particular exchanges in the area. Today I
had a long discussion with a tech from our local telco (Telstra) over
a users connection, his new house in a new estate was connected to a
non integrated RIM and the best speed he could obtain this morning
was 19200, this afternoon after they integrated the RIM his connect
speed went to 56000 with k56flex and he stayed on for his full
session time without dropping out, I got him to set his +MS=56 to a
maximum of 40000 and dialin again, his reverse speed was 28800, the
same as his 56000 connection which he is now getting consistantly
(after he remove the extra commands). So thats why I don't buy the
previous explanation (1) !!

for (2), I have some very knowledgeable telco techs amoungst my
userbase. One has been playing around actually in the exchange to
invesigate the 56k v's 64k channel business. In his words..... "I'll
be stuffed if I can get it to go any higher than 56000" for his
testing we actually set aside a BRI channel on a max 4000 with a BRI
card and had it connected using ETSI so the link was as direct as
possible (here to the exchange is 1.8km cable distance and he was
sitting in the exchange :-).

Gary

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