If my cable modem speeds exceed T1 spec, how is it so cheap?

Pandamonium

Golden Member
Aug 19, 2001
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I just ran some quick bandwidth tests and found that my upload/download performance to servers across the country are ~500k/sec down, 100k/sec up. Granted my specific cable modem's upload doesn't quite exceed T1 spec; but for my uses the download bandwidth more than makes up for it IMO. I also understand that I tested during off-peak hours; but generally I top out at ~700k/sec down and ~120k/sec up and rarely fall below 300k/sec down and 60k/sec up.

I thought that T1's advantages over cable and DSL were due to 24 channels instead of a single channel. In reading howstuffworks, it seems that a single channel is equated to a 8k/sec data transfer rate. If my understanding is correct, a T1, 1.5mbit SDSL, and any other connection offering 192k/sec transfer caps for downloads and uploads are all equivalent.

So what is it about T1's that give them such a high premium? (Excluding all wiring costs, since IIRC T1's use fiber optic before being split to coaxial.)

And if bandwidth is the single measure of line speed, am I correct in terming a 1.544mbit SDSL line and T1 line equivalent?

Edit: I just started wondering about this for some reason. Honestly, I don't really care what lines I use so long as they're fast.
 

jensenja

Junior Member
May 28, 2004
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The majority of your T1 lines are going to be copper, not fiber. The advantage T1 has is that you are guaranteed that speed no matter what, while cable speeds can and do fluctuate frequently. The purpose of leasing a T1 line is the premise that you are getting reliable, dedicated bandwidth.
 

vegetation

Diamond Member
Feb 21, 2001
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You hit it on the money with upload speeds. That matters a lot to people and more so companies who really need the T1 upstream speeds, and that speed rate is guaranteed. I'd bet your 100k/sec upload rate will fluctuate below that during peak hours. For someone who needs a reliable upstream connection, that would not be acceptable. The extra money for a leased line is chump change anyways to even a small sized company.
 

ScottMac

Moderator<br>Networking<br>Elite member
Mar 19, 2001
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True T1/DS1 is a dedicated circuit. If it happens to be a connection to the Internet, then you have a dedicated, (sort of) guaranteed 1.5 meg bidirectionally to the Internet.

DSL and Cable Data are running on a shared, oversubscribed, network. Statistically, most people get most of their bandwidth most of the time.

A true T1/DS1 also carries a higher level of reliability, is typically monitored 7X24, and receives a priority service level (compared to DSL or Cable).

Keep in mind that "All T1/DS1s are not created equally;" some carriers pay for higher service quality and deliver a better quality service to their customers.

FWIW

Scott
 

Anubis

No Lifer
Aug 31, 2001
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tbqhwy.com
what about optimum online in NJ

they offer 10/1 lines, the download is 6x that of a T1, even with cable slow down it wont ever slow below the level of a T1 and the upload is damn close 1 not 1.5 and its only like 40$ a month, cheapest T1 ive seen is like 300$ a month
 

mamisano

Platinum Member
Mar 12, 2000
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Optimum is really great with bandwidth. I also get 800+K down and 120K up. It was nice when I first got it YEARS ago and upload was uncapped and I could use a switch with multiple IPs... Ahhh, pre-Docsis was nice :)
 

spidey07

No Lifer
Aug 4, 2000
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as with all the other reasons listed here (reliability, guaranteed SLAs, complete remote testing ability, true TDM circuit)

And its that last part that makes it expensive. Time Division Multiplexing. It is ancient technology where you have 64K channels and the are all muxed up into larger circuits. It is wasteful to an extent and the hardware isn't cheap.

Hence why we started moving to packet switched networks in the 90s (frame-relay, etc)
 

choby

Junior Member
Jun 2, 2004
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I really wouldnt call it wastefull. Remember, the T1 standard came about for an easy way to mux voice circuits. Your local loop in analog and is vocoded at 8bits / sample at 8000 samples / sec. (8000Hz is needed to elimiate aliasing as stated in Nyquest's theory). This is where you get your 64k circuits. A T1 has 24 circuits meant to handle 24 voice calls. The whole telephone heirarchy was built off the 64kbps circuit (DS-0). So basically, you are adapting a voice network to handle Internet data, which it was not origionally intended to do.
 

spidey07

No Lifer
Aug 4, 2000
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Originally posted by: choby
I really wouldnt call it wastefull. Remember, the T1 standard came about for an easy way to mux voice circuits. Your local loop in analog and is vocoded at 8bits / sample at 8000 samples / sec. (8000Hz is needed to elimiate aliasing as stated in Nyquest's theory). This is where you get your 64k circuits. A T1 has 24 circuits meant to handle 24 voice calls. The whole telephone heirarchy was built off the 64kbps circuit (DS-0). So basically, you are adapting a voice network to handle Internet data, which it was not origionally intended to do.

and data networks for voice.

;)
 

choby

Junior Member
Jun 2, 2004
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touche

using a network created for voice, modified for data, and used for VoIP.

haha:D

probably get a few more than 24 calls on a data T1 using VoIP though. Interesting how it all circles around. A
 

spidey07

No Lifer
Aug 4, 2000
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Originally posted by: choby
touche

using a network created for voice, modified for data, and used for VoIP.

haha:D

probably get a few more than 24 calls on a data T1 using VoIP though. Interesting how it all circles around. A

and lets wrap a ipsec header around it while were at it so that the actual usable voice portion is but a fraction of the entire frame.
 

choby

Junior Member
Jun 2, 2004
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dont for get QOS, RSVP, or traffic shaping. Gatta make sure no packets are dropped.

I want 30 bytes of overhead for every 1byte of VoIP.

haha:laugh:
 

spidey07

No Lifer
Aug 4, 2000
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Originally posted by: choby
dont for get QOS, RSVP, or traffic shaping. Gatta make sure no packets are dropped.

I want 30 bytes of overhead for every 1byte of VoIP.

haha:laugh:

heh, I've been doing this crap for 10+ years and I still scoff at VoIP. It just ain't right. Just when we got networks doing well voice comes in.
 

JackMDS

Elite Member
Super Moderator
Oct 25, 1999
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While I agree with Scott, and Spidey's notions about T1, and there is no doubt that under certain circumstances it is still invaluable.

In reality I know many businesses that really do not need it and will save a lot of money and time if they would use Cable/DSL, Verizon is suppose to upgrade soon to 3Mb/sec. DSL at a consumer level .

The issue is that T1 came before the current availability of Broadband Internet. Business mangers are usually conservative and are afraid to change things that work.

It use to be: ?You can not go wrong if you buy IBM?. Oh wait a minute make it Compaq, AhAh now it is Dell.

As for VoIP. I have the feeling that it will join Powerline and Bluetooth.

:thumbsdown::thumbsup::thumbsdown::thumbsup::thumbsdown::thumbsup::thumbsdown::thumbsup:
 

spidey07

No Lifer
Aug 4, 2000
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Originally posted by: JackMDS
While I agree with Scott, and Spidey's notions about T1, and there is no doubt that under certain circumstances it is still invaluable.

In reality I know many businesses that really do not need it and will save a lot of money and time if they would use Cable/DSL, Verizon is suppose to upgrade soon to 3Mb/sec. DSL at a consumer level .

The issue is that T1 came before the current availability of Broadband Internet. Business mangers are usually conservative and are afraid to change things that work.

It use to be: ?You can not go wrong if you buy IBM?. Oh wait a minute make it Compaq, AhAh now it is Dell.

As for VoIP. I have the feeling that it will join Powerline and Bluetooth.

:thumbsdown::thumbsup::thumbsdown::thumbsup::thumbsdown::thumbsup::thumbsdown::thumbsup:

Jack,

Actually current trends are to replace private line networks (T1 based, frame, atm, etc) with DSL and VPN. While I don't like it (no quality of service, no control, etc) I've worked the numbers and my company can save over a million/year by switching.

that's pretty strong motivation.
 

ScottMac

Moderator<br>Networking<br>Elite member
Mar 19, 2001
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My problem with VoIP (as the owner of the "VOIPSUX.COM" domain - Hats are available) is that the traditional phone / POTS system is pretty much 99.999% available just about everywhere.

The typical business network (Spidey: I said "typical") ain't even close to that. ... nuts, even some Telco's Frame network isn't that good; remember a while ago when the entire Southwest region for (?SPRINT?, I think) went down (for WEEKS) because of an incompatibility during a code upgrade. Actually, that year there were two major Frame outages weeks / months apart.

The other problem I hear about with some frequency is the failure of the implementers to properly qualify the network (Code levels, current hardware, end-to-end latencies, bandwidth issues, etc) for VoIP. They do a few tests then plunk in summa dat new-cool-awesome-bitchin' phone stuff

VoIP can be a good thing if it's done right. The problem is that it usually isn't. It's not cheap ... you can't make it cheap (or cheaper than POTS) ... without sacrificing a LOT of reliability: You gotta buy it for some feature you need (or the president / CEO decides he needs from golf course conversations ...).

T1's absolutely have their place, and the place is smaller that it used to be, IMHO. If the DSL provider has business-specific infrastructure (or a whole lotta bandwidth with minimal oversubscription), then there's no reason not to use it if you can get it. The qualifier is how business critical the connection is, and the quality of the provider and their support organization. A bad judgement in that regard will have you saving money all the way to bankruptcy.


JM.02

Scott
 

spidey07

No Lifer
Aug 4, 2000
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Scott,

On the DSL route...I've been pretty darn happy with AT&amp;Ts IP offerings.

And yes, even some of the most resillient networks are prone to code problems and "weird stuff"

For example...all our backbone routers decided to lose their OSPF neihbors and rebuild their databases. ACK! 5 minute outage world wide.

Still having trouble figuring that one out.
 

TazExprez

Senior member
Aug 7, 2001
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Optimum Online from Cablevision is great. It's $45.00 per month if you have cable and $50.00 if you don't. It has a top speed of about 10Mbps/1Mbps. I have personally gotten about 9.4Mbps/1Mbps using a Speakeasy speed test.
 

spidey07

No Lifer
Aug 4, 2000
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Originally posted by: TazExprez
Optimum Online from Cablevision is great. It's $45.00 per month if you have cable and $50.00 if you don't. It has a top speed of about 10Mbps/1Mbps. I have personally gotten about 9.4Mbps/1Mbps using a Speakeasy speed test.

same here with insight. its freakin' awesome.
 

episodic

Lifer
Feb 7, 2004
11,088
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It is cheaper because they count on the fact that you are not going to saturate the pipe 24/7. If everyone saturated their pipe 24/7 I believe they could not keep up. Kinda like web hosts overselling. They count on 80 out of 100 people place a small static sight up.