OT: internet phones

[Fairlight]

This public service announcement was brought to you by Mike Schwartz (PC Support & Services, Appleton, WI):
>      My neighbors all told me their DSL was working great, but all they do
> is web browse and check their email, so they don't notice the little
> glitches in the connection. For example, if I try to start a telnet
> session or make a VPN connection or make an internet phone call, I
> drop my connection anywhere from 2 to 15 times a day!

You at the end of a cul-de-sac?  Could be nearing the edge of allowable
distance (18500 feet, if memory serves).  You could also have more than (or
close to) the allowable amount of internal phone cabling in your building
after the NID (3000 feet).  You could have a phone device that isn't
filtered.  Some people can get away with NO filters whatsoever and they
get full speed.  My in-laws have that good luck.  They're at the range of
allowable distance, too.  I used to be but was moved substantially inwards
towards a different CO when storms hit last summer.  However, I need
filters.  Phones (esp. cordless and newer ones with extra electronics in
them), caller-ID boxes, fax machines--anything you have should be filtered.
Don't filter each device.  Take each jack, unplug whatever's in it, and
filter it at the jack so you don't miss anything.  When I first started
up, we pulled our hair out trying to find the reason my connection was
-inverted-.  I have a 1.5/256 line that was giving me 27KB/sec uplink but
only (at best) a spotty 1 to 4 KB/sec downlink, with intermittant sync, no
less.  Found that I'd filtered individual devices separately and missed an
older caller ID box.  Moved filters to the jacks before all the cabling and
all devices and voila, pure 1.5/256.  You can also get a splitter to put in
at the NID that will let you split off the DSL signal to ONE jack in your
house.  They cost about $50-70 online, and are -not- something you'll be
able to pick up locally.  They're basiclally industrial strength filters
that just go in a the NID level.  I know someone that actually cobbled a
regular filter into doing this at the NID. :) Worked for him.

DSL is a touchy and fickle beast.  And it gets bursty for a lot of people
during periods of high EM interference (like during thunderstorms).
Hot/cold extreme weather changes can change the conductivity of the
line and also expand/contract materials in the connections, changing
line conditions between winter/spring and summer/fall.  Changes of
10-20KB/sec aren't unheard-of.  Oh, and you can have a connection degrade;
it basically runs on channels.  Each channel, from what I've been able
to tell empirically seems to be responsible for about 4KB/sec worth.  If
a channel degrades enough, it will be flagged as unusable.  Enough get
flagged for whatever reason, speed drops, drops, and finally you might not
even have sync.  A fast reset of the modem won't help.  You have to leave
the DSL modem off for 45-60 seconds and give the system time to clear the
flags on the channels so they're marked usable again.  Last tests they ran
before switching me to interleave showed that 90% of channel frequencies
were flagged unusable to me -at all-.  It's a miracle it works.  And that's
at 13000 feet from the CO.  Used to be at 18000 before they changed
infrastructure.

When it works, it rocks.  When it's problematic...well...   *cough*

Let's just say it's -not- a T1, as denoted by the respective costs.  :)

Also, ping the router just the other side of the gateway.  What's your
average latency?  If it's ~15ms or so, your line may be set to fast-track.
That setting is not usually the default in most areas, but it was in mine.
Fast-track will try for maximum performance, but it falls on its face a lot
easier than the alternate setup.  If your latency is that low, ask your
provider about getting it switched to interleaved mode.  This will add
about 35ms latency (you'll average around 50.5ms or so on the link itself
instead of 15.5, for instance), but the extra robustness of interleave more
than makes up for the tiny, unnoticeable (and I'm a heavy gamer--you'd
notice this in a first-person shooter if it was a problem, and it's not)
extra latency.

Just a thought.

BTW...the interleave mode is sometimes referred to as a "applying a noise
profile" by some carriers, if you need to ask for it and run into someone
at customer service that doesn't have a clue.

Common DSL interference issues also include running the phone line (even
in another room) within 6" of a UPS, running phone line parallel to
flourescent light ballasts (you want to run it perpendicular if you can't
avoid running it near them at all), and running it past rheostats (ie,
dimmer switches).  All common "gotchas" that can affect DSL.  Anything EM
that isn't well shielded is a suspect, but those are some of the more
common factors.

There's a whole laundry list of things to look for when tracking down DSL
issues.  When we had the initial installation issue until I found that
caller-ID box that was hiding on me, I learned pretty much most of them.

Heck, check your cabling.  Sometimes it's as simple as a bad contact in the
modular plug on the cable between jack and modem.  You can bend it to one
side with a fraction of an ounce of pressure and fix the problem.  Not
unheard-of, either.  A lot of cable out there is made like crud.

OTOH, it could be a failing or faulty DSLAM in the switch.  I'd tend to
think they'd notice that though, as it would affect everyone--but as
you've noticed, usage patterns (and certainly reporting tendencies) tend
to differ.  It probably isn't this, but if you bug them enough, they could
discover it during testing.  Thing is, most carriers don't have speed
guarantees.  In most areas DSL is a "best effort" service due to its very
nature, and with BellSouth in particular it's a case where there is NO
complaint option for bad speeds.  You can claim intermittant sync, and
they'll look into it.  But the only speeds they will do something about
are so low that your DSL wouldn't even sync at all, which means that you'd
be reporting an intermittent sync or no sync, not a speed issue.  And
actually, while it may be (in my case) a 1.5/256 line, the actual sync rate
fallback is 128kbit.  If it falls below that it won't sync at all.  So you
can definitely be paying for what you're not getting and have no recourse
other than changing service.  BellSouth's higher-end "guarantee" is that
they'll try to give you that line speed--but if they can't and you're not
satisfied, you can punt and drop the service.  That's as far as they'll go,
and they're not alone.

>      This is very frustrating when I'm trying to do filePro programming
> using ssh.  The only way I can get any work done is with tools that
> will allow me a "persistant connection", like PC-Anywhere.

I'm assuming you mean it's very lag-tolerant and doesn't hang up at the
drop of a pin.  (Incidentally and OT, one night about 1995 Sprint calls me
trying to get me on their LD plan at the time.  I couldn't hear the sales
rep for all the static, it was so horrible.  Finally (and knowing I didn't
want to drop MCI anyway), I just said, "Sorry, I can't hear you for the
static--must be the sound of all those millions of pins dropping!)  :)

>      Anyway, I'd hate to trust my phone calls to my DSL connection.

My DSL isn't the factor here--except in storms.  And it depends on the
storms.  We had tornado warnings up the wazoo here last week (like we could
hear the whole county's civil defence, not just our local tower--ALL the
towers), huge T-Storms, hail galore...  Really it's the lightning that
does it, and it's been lightning a LOT.  Even 2 nights ago we had brownouts
and the like (my UPS briefly tripped twice, although my wife's unprotected
system never lost power).  Usually if it's that bad, the connection will go
from like 157KB/sec down to a bursty 70KB/sec or so.  Didn't drop, really.
Over a 12MB download from just the other side of the router (best benchmark
you can have, really--something JUST the other side of the router, and in
ftp rather than http), I get like 3% per line with wget, and it'd be mostly
148KB/sec lines with the occasional 123KB/sec line every 9 lines or so.
Not bad at all.  I've had storms that took me down to a max of 120 once
every 9 lines and an average of bursty 40-50KB/sec.  It just really depends
on the storm.  Sometimes it does nothing.  We played EverQuest straight
through that bad one the other night and never noticed a thing, even using
TeamSpeak at the same time.  Other times the line gets funky 40min before
it hits and stays that way until up to an hour after it passes.  EM is not
an exacting science, and I've -seen- our line to the building--it is NOT
shielded correctly.  The fact that DSL relies on the highest frequency part
of the transmission (and therefore the easiest to roll off) does NOT help
matters.

Oh, one thing that will happen, as long as I remember it, is that
especially after a brownout or power fluctuation, some channels tend to get
marked as bad.  Resyncing manually after a 45-second downtime on the modem
clears this.  That's pretty common, actually.   Note that there is a
difference between the modem auto-resyncing and doing a manual power cycle
delay resync.  Notably, you give the equipment at the CO time to unflag the
channels--time it doesn't have on an auto-resync.

> telephony isn't ready for prime time yet.  Or, maybe it's just the
> low grade of wireless internet service I get when I'm staying in
> cheap motels that's making the difference <grin>.

Wireless interference (and I speak as someone whose apartment is like an EM
black hole, I swear) can be a real PITA.  I can get up to 72mbit--or it can
fall to 5mbit or cut out for a few seconds to a few minutes.  It depends on
the alignment of the planets, phase of the moon, how many runes I've drawn
in goat's blood on the wireless router, and one's astrological reading for
the day.  Someone turns on a microwave and it can bottom out.  I have a
Logitech WingMan gamepad that runs in the 2.4GHz range and takes me from
72mbit to 5mbit instantly--despite their claim they tested it with hundreds
of wireless network devices.  I can't use it if I want better than T1 speed
on the LAN.  I keep it disabled at the USB hub level unless I'm using it.

No stranger to wireless interference and overcrowding here, either.  I
have 108mbit wireless equipment, but in reality it hovers around 12-48mbit
and almost constantly fluctuates.  Which is still wider than my DSL even
at 5mbit, so I never really notice the difference unless I'm copying
hundreds of megs across the LAN.  Then I can watch the ETA reading go up
and down like a sorority girl.  I kinda notice when it entirely desyncs,
but that happens like once a month, if that.  No biggie.  It's the price of
convenience for having zero wires between rooms.

Good luck on the DSL.  Maybe something listed up above will help you.

mark->