[lug] residential T1
nate at natetech.com
Mon Aug 7 07:48:42 MDT 2000
On Mon, Aug 07, 2000 at 02:17:34AM -0600, Sean Reifschneider wrote:
> On Mon, Aug 07, 2000 at 01:24:01AM -0600, Nate Duehr wrote:
> >T1 is provisioned over plain ol' copper. Distance limitations apply,
> >but are more flexible than DSL. There's also the usual requirement for
> Distance limitations? Point To Point T1s are priced based on distance,
> and running from Fort Collins to Boulder isn't anything overly hard for
> them to deal with. I've dealt with T1s running from Washington state
> to Colorado... They aren't cheap though. Fort Collins to Boulder is
> around $800/month just for line charges...
Sorry, let me clarify... distance limitations without being regenerated
(which is easy to do). Most long-haul T1's look something like this...
Customer: <DSU/CSU>-<Copper>-<Crossbox>-<Copper>-<Central Office>...
ISP: <CO>-<Fiber>-<3:1 Mux>-<DSU/CSU>
My point was that the only copper portions are the "local loop" to the
residence usually. The ISP probably has their own channelized DS3's.
The distance limitation portion is the part about the copper local
loop... you may need a repeater or two if you live a long way from the
CO, and they usually show up on your bill in the form of mileage
> >telephone lines and puts them into multi-T1's upstream. Telco's like to
> >blame fiber because it sounds a lot better than saying that they've been
> Most of those problems that I know are because they run fiber from the
> switch out to a pedestal in your area, and from there break down the
> N 64kbps channels into a bunch of copper pairs. They're still giving you
> 64kbps though, it's not like those multi-line concentrators that are
> commonly installed to give you two lines over one pair in the neighborhoods
> where they don't have enough copper to the houses...
> Are you sure that they're cutting into your 64kbps channel when using these
> fiber extenders?
Like Perl, there's more than one way to do it. Older neighborhoods have
SLC-96 and channel-bank equipment, and those are NOT compatible with
V.90, the 56K modem specification, at all. (There's a specific number
of D-to-A and A-to-D conversions in the spec. The head-end or ISP HAS
to have a direct digital modem pool to meet the V.90 spec. It's
interesting reading... makes ISP's with a bunch of analog modems piled
on top of each other and analog phone lines look pretty silly when they
claim to be 56K. Impossible technically.)
> Last time I was pulling a lot of phone lines into a house though, they
> actually pulled in extra copper to my house -- I had 6 lines at the
> time. They even asked me what I thought I'd need in the future, I
> told them to put in a couple of spares...
Yep, houses seem to have more and more copper in them. USWest is
getting better about putting more copper in the ground, too. But
there's a lot of places where growth has tapped out the available
underground copper and USWest is doing "pair recovery" -- go back and
look for unused or forgotten pairs. (It happens.)
> >of those circuits because of the extra A-to-D conversion done in the
> AFAIK, once you go from A to D at the pedestal, you're digital back to the
> switch and probably digital all the rest of the way to your destination
> switch where it'll eventually get turned back into analog.
It's not the quality or location of the A-to-D conversion, its the
number of them in an analog phone line that determines its usability for
56K (V.90) service.
> Now, the question is: Why aren't they installing DSLAMs in the remote
> boxes where they put the equipment that takes fiber and turns it into
> copper? When I was up in Canada I asked the tech installing my ADSL
> line about that and he said that's exactly what they were doing --
> they could offer ADSL to 95% of the phone subscribers in the city.
> Apparently the story is that USPest doesn't want to install them there
> because then they'd have to open those boxes up to JATO and the like
> to install THEIR equipment in. So, you don't get DSL because the telco
> is afraid of competition. That's just a story I heard from a reliable
> source who heard it from a "Whatever they want to call us this week"
I can't refute or support this one, but I wouln't be surprised. What I
do know is that with the strict distance limitations on DSL (15,000 or
so cable feet with 24 gauge copper wire) that there's a LOT of work to
put in all this stuff. That little box in your neighborhood often-times
has nowhere to draw power from. DSLAMS, SONET gear, blah blah blah, all
require power to operate. And if the phone lines being sent over those
circuits are residential or primary to a business (which means they
might be used for 911 service) they have to be backed up by UPS by law.
Fun stuff, Outside Plant is. :)
> That was, IIRC, the same technician that was telling the story about
> how they had gotten a call telling them not to wear any USWest clothing
> or other things that said USWest on it, until the new QWorst clothing
> could be rolled out. "Yeah, except I'm driving around in this truck
> with *US WEST* written all over it in foot high letters!".
Sounds like the Frontier/Global Crossing merger, which I was privy to.
Not clothes, but other silly things like that.
> >Many ISP's require that you buy the half of the circuit that goes to
> >THEM also, your side alone won't cut it. And some, like the
> PTP T1s are dedicated circuits, so it's not really broken up into
> "ends". A Frame Relay T1 for example can have multiple clients
> hanging off one line at the ISP side, but a PTP T1 is just like
> a wire from you to your ISP. The problem is that Frame Relay
> costs around $375 per end (but no distance charges).
I understand that, but the original posters message didn't mention
anything about point-to-point, and USWest is just dumb enough to
provision you a T1 to the CO and then wonder where you want it to go
from there... :) Just checking on that one!
> >Also, if you go the Co-Op route, make them GUARANTEE you a throughput
> >rating to somewhere UPSTREAM. If you've ever seen their MRTG graphs
> >from their routers, you'll know why I say that. Their pipes are
> I've seen their MTRG graphs and the coop seems to be VERY good about
> proactively getting bandwidth. Considering that they're mostly installing
> DS3s, and those can take months of negotiations, they seem to do a
> pretty good job of it, but that usually means that by the time one
> DS3 is in they're starting the process for ordering another one.
> Of the ISPs in the area, the COOP is most likely to be able to give
> you bandwidth and lots of it, unless you start going for the big
> national backbone providers charging (as I understand it) around
> 3 to 5 times the cost.
Good point, I'm used to playing with the UUNet's and Digex's (Genuity
now?) of the world. I forget that your only other choices in Boulder
are just as badly oversubscribed local ISP's in many cases... or they
soon will be. But the point still stands, you get what you pay for. :)
> >From my examinations of the MRTG graphs, I can't say that it looks
> like the coop is oversubscribed on their upstream bandwidth, but
> I haven't really been watching it over the last 6 months.
> >"router/network" device and using up the D-channel since it's not in
> >use. Therefore 144Kb/s instead of 128Kb/s and an idle D-channel.
> And a little cheaper. I believe it also connects into the ATM network
> and terminates at the ISP in their DSL Megacentral, which can mean you're
> getting DSL pricing instead of ISDN pricing (which for dedicated lines
> can still be quite expensive).
True, true. Watchin' the game, drinkin' a Bud...
The interesting part about bandwidth is that what was "difficult and
expensive" yesterday is commonplace and inexpensive today. I remember
when getting T1's was difficult and expensive. Fiber changed all that,
and made local loop DS-1's almost as reliable as power service from
PSCo. I'm looking forward to the day when the next jump in bandwidth is
"easy" and Residential T1's look like child's play. :)
Nate Duehr <nate at natetech.com>
GPG Key fingerprint = DCAF 2B9D CC9B 96FA 7A6D AAF4 2D61 77C5 7ECE C1D2
Public Key available upon request, or at wwwkeys.pgp.net and others.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Size: 232 bytes
Desc: not available
More information about the LUG