question on DSL signal

Ted Mittelstaedt tedm at
Thu Feb 7 12:36:10 UTC 2008

> -----Original Message-----
> From: owner-freebsd-questions at
> [mailto:owner-freebsd-questions at]On Behalf Of David Banning
> Sent: Monday, February 04, 2008 12:02 PM
> To: questions at
> Subject: question on DSL signal
> I run a small FreeBSD server with a standard DSL line. I have it ping
> the ISP every five seconds, and when it doesn't ping it logs the
> results.
> 3. I have used three different DSL modems, but the are all home
>    quality: an Alcatel Speed Touch, a Speedstream 5260,
>    and a Westell Wirespeed. Would spending more money on
>    another type of modem help? If so, what is recommended?

I work at an ISP and do this stuff for a living.

Westell makes some very good DSL modems.  The 2100 and the
35R515, 516, etc. series are great.  These are dumb bridges,
so your BSD system must speak PPP if thats what your ISP uses.
(we don't, we use bridged mode)

There's a program (wdiag 0.9) you can compile that will query the
36R51x series of modems for statistics.  Here's an example
from my own home DSL line plugged into my FreeBSD system:

mail# pwd
mail# ./wstart
mail# ./westell
Uptime Counter: 24696500
Upstream SNR: 90
Upstream Power: 120
Upstream Attenuation: 315
Upstream Sync Rate: 768
Downstream SNR: 50
Downstream Power: 180
Downstream Attenuation: 535
Downstream Sync Rate: 1536
FEC Errors: 0
CRC Errors: 0
HEC Errors: 0
Signal Lost: 0
Frame Lost: 0
Tx Cell: 7071744
Rx Cells: 8183507
Dropped Cells: n/a
Rx Ethernet: 60256998
Tx Ethernet: 55199128
Discarded Ethernet: 0
mail# ./wstop

Anyway, as the other poster said, your problem is copper.  Your ISP
has to just keep calling the phone company and dispatching a tech
out there.  Weekly if necessary.  We had the same problem with one
of our customers provisioned through Verizon.  It went on for months
and the customer was under the impression that the problem was the
modem, so every time she had a problem she would call up and ask
to have her modem exchanged.  I must have put a dozen modems out there,
and of course the returned ones tested fine.  I knew the problem
was wiring not the modem but the modem swap thing made her happy.
(no big deal for us we just gave the modems to other customers)
The problem with dispatching a tech was that she was never home
and her MPOE was in a dog run, and she wasn't really willing to
setup access for the phone techs to get to the MPOE.
Finally one day a tree fell in the neighborhood and knocked down a
phone pole.  After Verizon repaired that, problem vanished.
The tree was about 3 blocks from her house.

For instances when the customer was willing to stick around to
let the tech have access, it usually takes about 3 dispatches on
the tough ones before they are fixed.  The local phone company
dispatcher is wise to the deal and when they see multiple repeat
calls to the same site they will send out their experienced linemen.
The greenhorn linemen can't troubleshoot DSL worth crap.  Just
keep on dispatching them.  The tech guys at the CO can look at the
DSLAM statistics and see the same thing that you can see if you
query the modem stats, and if your copper is bad it can't be hidden
in the stats.

As for all the talk about the phone company not caring, that is
baloney.  The phone company is very interested in DSL and works
to fix the problems.  It is true that some linemen think DSL is
a waste of their time and don't lift a finger to actually get
in there and feel around for the line problems.  But this isn't
the corporate party line on DSL at any phone company, and if 
you get blown off by a lineman giving you a raft of crap like 
they can't fix it, call the ISP and the ISP can force escalation
and get a manager in there who can get a different phone tech
who knows what he's doing.

This stuff isn't rocket science, frankly your problem is your
ISP, unless of course your using the telephone company as the
ISP also, in which case your not ever going to talk to anyone
competent.  Good luck with that.  There's a reason people use
3rd party ISPs.


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