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Psionic Pulse
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Joined: 17 Jun 2003
Posts: 19
Location: Portland, OR
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 Posted: Thu Jun 26, 2003 12:07 am Post subject: EDIT: HELP!!! IS MY T1 A DSL LINE?!?!?!??! |
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Can someone please explain to me Telextend? It's Covad's "T1" technology. All i keep finding is that Telextend is DSL using T1 circuits. Covad keeps telling me that the connection is 1.5 Megabytes per second. Someone correct me if i am wrong, but that comes out to about 12 Megabits per seconds. Now.. Also.. Please correct me if I am wrong in my thinking (tho i'm about 99.999999% sure of this) that a T1 is 15 Megabits per second, which comes out to about 1.875 Megabits per second.
Is this a blatent rip-off? Covad calls it "True T1 Service for buisness with high bandwidth demands".. but.. if those numbers are correct, then it's NOT "True" T1. It's just #@#$! DSL!!!
Any comments?
-Psi
Last edited by Psionic Pulse on Thu Jun 26, 2003 8:05 pm; edited 1 time in total |
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devon
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| Posted: Thu Jun 26, 2003 12:12 am Post subject: |
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Covad keeps telling me that the connection is 1.5 Megabytes per second
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Wrong! A T1 circiut is approx 1.5 Mbps (Megabits per second).
A T1 has 24 64Kbps channels. Check out All You Wanted to Know About T1 But Were Afraid to Ask. |
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Psionic Pulse
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Joined: 17 Jun 2003
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Location: Portland, OR
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| Posted: Thu Jun 26, 2003 12:24 am Post subject: |
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well ok.. 1.54.. but still that's slower than what we're being sold by covad.. correct?
-psi
edit: just to ask a few more things.. is anyone confused by the fact that the router connects over PPPoA, and that the install was DONE (from order to circuit-up) was a little less than 2.5 weeks? |
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xrn0id
Tux's lil' helper
Joined: 24 Jun 2003
Posts: 107
Location: /usr/USA/
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| Posted: Thu Jun 26, 2003 12:31 am Post subject: |
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Http://www.dslreports.com/speedtest
Go there for me, and see what speeds you get and post them onto the board. I have a 2 Mb cable line... thats about 250 KB/ps.
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devon
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Joined: 23 Jun 2003
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| Posted: Thu Jun 26, 2003 12:31 am Post subject: |
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Did Covad say 1.5 Megabytes per second or megabits?
There is 8 bits in 1 byte. So 1.5 Mbps is approx 187.5Kbps.
| Quote: |
edit: just to ask a few more things.. is anyone confused by the fact that the router connects over PPPoA, and that the install was DONE (from order to circuit-up) was a little less than 2.5 weeks?
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Hmm... I would say the underlying circuit is DSL. All the T1s I have ever installed use HDLC or PPP and take 30-60 days to provision. 
Edit: Fixed typo
Last edited by devon on Thu Jun 26, 2003 12:42 am; edited 1 time in total |
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Psionic Pulse
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Joined: 17 Jun 2003
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Location: Portland, OR
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| Posted: Thu Jun 26, 2003 12:34 am Post subject: |
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| they did say 1.5 megabytes per second.. |
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jimlynch11
Guru
Joined: 21 Feb 2003
Posts: 590
Location: massachusetts
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| Posted: Thu Jun 26, 2003 12:37 am Post subject: |
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after this thread, i discovered bandwidthplace.com no longer does speed tests...
booooo! |
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Psionic Pulse
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Joined: 17 Jun 2003
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Location: Portland, OR
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| Posted: Thu Jun 26, 2003 12:40 am Post subject: |
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Dsl reports say:
Download: 1283kbps
upload: 1294kbps
-psi |
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devon
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Joined: 23 Jun 2003
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| Posted: Thu Jun 26, 2003 12:41 am Post subject: |
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they did say 1.5 megabytes per second..
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I would talk to your sales person and clarify this. Most sales people do confuse terms and we engineers have to correct them.
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Download: 1283kbps
upload: 1294kbps
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Or 1.283 Mbps. Looks pretty close to a T1 considering protocol overhead. |
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Psionic Pulse
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Joined: 17 Jun 2003
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Location: Portland, OR
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| Posted: Thu Jun 26, 2003 12:46 am Post subject: |
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| devon wrote: |
I would talk to your sales person and clarify this. Most sales people do confuse terms and we engineers have to correct them. |
Believe me i know. Yeah.. we're trying to get a copy of the contract (that we've yet to sign oddly enough) so we can see what the exact specifications are..
as far as I can tell, Telextend is like T1 over DSL, or.. DSL over T1 or ... i'm not sure which..
It's a T1 local loop, that is multiplexed with the DSLAM as soon as i leave the building... which means it's.. Shared bandwidth, cause it's multiplexed in with the other DSL lines in the area...
-psi |
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Psionic Pulse
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Location: Portland, OR
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| Posted: Thu Jun 26, 2003 12:47 am Post subject: |
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Just guaranteed 80% of that speed.. which .. makes me feel that it's DSL as well..
-psi |
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Psionic Pulse
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Joined: 17 Jun 2003
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Location: Portland, OR
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| Posted: Thu Jun 26, 2003 12:55 am Post subject: |
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well here's what i found.
Covad's Telextend service is also delivered over a T1 Local loop. In the central office it terminates into one of Covad's existing DSLAMS (DSL access Multiplexers). Internet access is then acheived through Covad's ATM network (the same network they use to provide DSL service). So although this is a T1 Local Loop, actual throughput will be subject to the Quality of Service options used to provision the connection across their ATM network. I could not get details from Covad on what kind of ATM PVC would be used. If it has a CBR (constant bit rate) with a high value (eg 1.5Mbps, then this service should provide equivalent T1 throughput. However if they use Unspecified Bit Rate, then i'd be very wary as you'd be competing for shared bandwidth with their existing DSL users."
what do you make of that?
-psi |
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puggy
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Joined: 28 Feb 2003
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Location: Oxford, UK
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| Posted: Thu Jun 26, 2003 1:12 am Post subject: |
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When talking about data transfer rates bits are always used because it doesn't make sense to talk about bytes as for this purpose the fact that there are 8 bits in a byte is arbitrary. If your going to talk about bytes you might as well talk about a bakers dozen. 
Puggy
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devon
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Psionic Pulse
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Location: Portland, OR
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| Posted: Thu Jun 26, 2003 3:15 am Post subject: |
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No. I'm more confused about it connecting to the DSLAM. i thought it went straight to an ATM interface. i will admit, it's been 3 years since i was a T1 tech, and havent touched one since so... i could be completley wrong.. if i am, sorry for bein a dumbass.
-psi |
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devon
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| Posted: Thu Jun 26, 2003 3:27 am Post subject: |
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| Psionic Pulse wrote: | | No. I'm more confused about it connecting to the DSLAM. i thought it went straight to an ATM interface. |
Disclaimer: I have never worked on a DSLAM, so this is all pure conjecture
I would imagine that all the DSL lines terminate into the DSLAM, where it then plugs into the ATM network. From there the DSL lines are assigned VCI/VPIs to traverse the Covad ATM network.
Regardless, these are valid concerns and things I would ask your sales person about to make sure you understand what you bought and what happens if Joe Blow decides to mirror alt.binaries.vcd.  |
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Psionic Pulse
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Joined: 17 Jun 2003
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Location: Portland, OR
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| Posted: Thu Jun 26, 2003 3:41 am Post subject: |
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Well.. ok.. my primary concern is that the link from the DSLAM to the ATM cloud would be congested because of the local DSL traffic running thru the DSLAM to the ATM cloud.
I guess it's just the whole TeleXtend system that allows it to run thru the DSLAM... But it doesn't seem that bad.. The network is responding appropriatley in each of the separate areas. So it feels like a T1...
We'll see what happens.. thanks for your help guys.
-psi
P.S. by reading this thread, you now know more than the Level 2 Techs @ covad. ^_^ |
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milkdi
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| Posted: Thu Jun 26, 2003 4:02 am Post subject: |
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actually, the speed from the DSLAMS to ATM is nothing that you can tell or change.
Even if you have a T9999 from your office/home to the provider, it all depends on the pipe of the provider to the internet, which is actually what matters the most.
That being said, I think their ATM will be good enough for you. 1.5mbps isn't really a big pipe in telco terms. |
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devon
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| Posted: Thu Jun 26, 2003 6:15 am Post subject: |
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| milkdi wrote: | | actually, the speed from the DSLAMS to ATM is nothing that you can tell or change. |
Oh trust me... If you bitch enough they can upgrade their interconnects. I had a friend who moonlighted at the local LEC and there was a note in my "file". Let's just say, they didn't think highly of me and my non-stop phone calls.
Granted, I was calling on behalf of an ISP and not a residential customer. |
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milkdi
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| Posted: Thu Jun 26, 2003 8:28 am Post subject: |
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well the point is, all you have is a T1, even at its peak bandwidth it's only 1.5mbps.
A single DSLAMS support maybe at least a few hundred to thousands of DSL lines. So for just weak/normal performance, it will still have way more bandwidth than you T1. Therefore, no worries |
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MacMasta
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| Posted: Thu Jun 26, 2003 4:50 pm Post subject: |
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Question: I was under the impression that a "T1" (or a "T3", etc) was hardware-independent.
That is, any pipe, whether dsl, cable, (massive-parallel-dialup?) that provides 1.5Mbps is a T1 and any that provides 45Mbps is a T3, and so on.
So, assuming your speed is high enough, you have a T1 over DSL, right?
~Mac~ |
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devon
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Joined: 23 Jun 2003
Posts: 943
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| Posted: Thu Jun 26, 2003 4:58 pm Post subject: |
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| Quote: | | That is, any pipe, whether dsl, cable, (massive-parallel-dialup?) that provides 1.5Mbps is a T1 and any that provides 45Mbps is a T3, and so on. |
Not quite true. Most pipes that are >1Mpbs have the generic term of being "broadband". But a 1.5Mbps cable/DSL line is not a true T1 as it has different signaling. See the site I posted earlier in the thread. It will explain the T-carrier hierarchy in great detail. |
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Psionic Pulse
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Joined: 17 Jun 2003
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Location: Portland, OR
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| Posted: Thu Jun 26, 2003 8:04 pm Post subject: |
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See that's what i'm trying to determine.. It's a T1 that multiplexes with the DSLAM, AND runs over PPPoA... so i'm not sure that it's a "true T1" which puts us in an odd spot (being a lan-center). If we Advertise having a T1, and we have DSL (even if it's sold to us as a T1) then we're falsly advertising.
-psi |
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Athlon_Jedi
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Joined: 25 Jun 2003
Posts: 45
Location: Tifton, GA
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| Posted: Fri Jun 27, 2003 1:44 pm Post subject: no no no |
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T1 and xdsl are two totaly seperate technologies, more than likely what they are doing is connecting you to the co using dsl then the co pipes all its traffic over a t-1 line thus allowing them to legaly claim it is operating at a t-1 bandwidth when in effect it acculy is a higher bandwidth dsl line. xdsl will support speeds up to 8 mbps so basicly all they are doing is routing all the traffic comming in and out of the co through a t-1 instead of the usual dc3 or so.
its a dirty trick in that all they have really done is set your dsl cap at a higher bandwidth than normaly would be applied. if you ask me its a rip off. but just a legal one. |
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kashani
Advocate
Joined: 02 Sep 2002
Posts: 2032
Location: San Francisco
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| Posted: Fri Jun 27, 2003 8:37 pm Post subject: blah blah DSL |
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| Psionic Pulse wrote: | See that's what i'm trying to determine.. It's a T1 that multiplexes with the DSLAM, AND runs over PPPoA... so i'm not sure that it's a "true T1" which puts us in an odd spot (being a lan-center). If we Advertise having a T1, and we have DSL (even if it's sold to us as a T1) then we're falsly advertising.
-psi |
In these post boom days some technology has been deemed "unfancy" and marketing people like to think that refering to it by other names makes it sexier.
You have SDSL aka symetric DSL which supports 1.5mb/s up and 1.5mb/s down. We know this because your line requires ATM and a DSLAM, two fairly expensive technologies that are not required for terminating a T1 and routing IP traffic over it.
DSL lines are cheaper than T1 local loops hence the price difference between an actual T1 and the quick install time.
The speed you can attain to the Internet at large is dependant on a few factors.
1. Congestion on the local network, aka from the local POP to the core.
2. Your ISP peering or transit agreements
3. The congestion at the far end.
These factors are the same no matter what technology you are using for the last mile. Obviosuly the first two are the only factors you have some influence on... mostly by changing your provider or harassing them.
Again in the post boom Internet internal congestion is fairly rare. A DS-3 could be installed today for the price of a 1997 ds-1 in many cases, especially in metro areas. Peering and transit agreements are more a mixed bag, but again pulling circuits and paying for bandwidth at the ISP level is a fraction of the cost it used to be. Also ATM allows some QoS stuff where T1-really-DSL connections could be set to take preference over joe bob's home DSL. You might want to ask about that.
The real question is, "Are you happy with your connection and speed for the price you pay regardless of what people decided to call it this week?"
Whether you call it a T1 or DSL in your marketing speak is up to you, but the differneces between them in this case is negligible from a speed perspective. Personally I'd think any perspective customer should be more concerned about what your 2nd connection to the Internet is.
kashani, who worked for the first company to offer DSL connections to the consumer
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