first off I have adsl the rated speed on my line is 1.5 kbps I can configure a router and network a few users or clients to that line. I've been reading faqs about T1 they are saying u can put up to 200 users on a single T1 how is this posible when only a full T1 is 1.5 kbps? Also a full T3 is 44 kbps how is this posible? I know a T1 has its own circit too. but things just dont add up to me just was wondering thank you gdog_01

I am afraid you need to check your numbers. A T1 is roughly 1.5MB not kb and T3 is 45MB not kb. See the difference.

I didn't mean to post so quickly. As I was saying even if you meant you were getting 1.5 Mb on your DSL that is MegaBits not MegaBytes. A T1 gets 1.5 MegaBytes Here is an explanation of the difference from Crucial.com "Bits and Bytes A bit is a single character of data (a 0 or a 1). A byte is eight characters of data. Therefore, eight bits make a byte. Your computer processes information in a series of eight bits, or, one byte. Here's where the numbers can get confusing. To make a 128 megabyte module, you need eight 128 megabit parts. (Remember, it takes eight bits to make a single byte. So multiply 128 megabits by eight parts and you get a total of 128 megabytes.) " So, in essence you would really need Eight DSL lines to equal one T1. I think.

I always thought Bits and Bytes where the same thing. I understand though thankx for clearing that up. Gdog_01

residential adsl (light) is near 1Mbps, corporate adsl is about 3Mbps. However both of them are asyncronous because their respective upstream bw are 128Kbps and 640Kbps only.... T1 and T3 are syncronously rated @ 1.5 and 45Mbps. Also, when you pay for a T1, your upstream provider reserve the equivalent bandwidth on their border side. The remaining is shared between all Adsl customers... this is why xDSL are so cheaper!

I do this professionally. DSL is actually a series of different products...There is ADSL, SDSL, HDSL, IDSL, and a few others. The first, most common in residence, is ADSL. Asychronous DSL. The reason it's considered Asychronous because the upstream rate and the downstream rate are different. The upstream rate is typically about 128k to 256k, depending on how generous your provider is. You downstream rate is usually 1.544 Mbs. SDSL stands for Sychronous DSL which means its even steven up and down stream rated at 768kbs. HDSL is Highbitrate DSL which is 1.544 Mbs upstream and downstream. Finally IDSL is the ISDN form of DSL. That is to say if you formally had an ISDN line rather than a POTs (plain old telephone) line like the standard resident you would use IDSL rather than ADSL. As for T1. T1 is a digital framing standard in the carrier world. It is equal to 1.544 Mbs. This is how carriers draft your traffic and mine togehter into the network world. side bar - If you ever read anything or hear some one talk about a DS1, its the same thing. I wont bore you with the symantics in the subtle difference, you would be perfectly correct to say they are the same. The T1 is divided into what is called 24 channels. Each channel is equal to 64kb. minus overhead and you get 56kbs. Sound familiar, thats right folks, just like the old modems which were rated at 56k. Now here comes the confusing part. A T3 does not equal 3 T1s (dont know why, dont blame me, AT&T made this crap up). A T3 equals 28 T1s. But let me get to your confusion on how 200 people can be on one T1. The deal is, is that the carriers try to get the biggest bang for the buck, so what they do is "oversubscribe". That is to say, they assume that you and I will not access the same amount of bandwidth at the exact same time. So although there is only one T1 for us both, your carrier will put 4 or 5 of us on the same T1 figuring on the law of probability that we wont use it at the same time "too often". They expect some overlapping usage, which is why you and I are sometimes gripping about the "connection is slow today", its because we are jamming the pipe (T1) at the same time. Now it gets worse. There are three teirs in to get to the internet. Teir 1 are the big boys like UUNET. Teir 2 is the next big wigs like Bellsouth or somebody like that, and Tier 3 are the ma and pa internet providers. Each does the oversubscription...that is to say UUNET overscribes but 4, then Bellsouth oversubscribes by whatever, say 4 again, and finally ma and pa ISP oversubscribe by another 4, that means that when it gets to you and me, we've been oversubsrcibed to the internet by 4x4x4= 1 to 64. And these are nice numbers, its actually worse. But if ma and pa dont oversubscribe they cant keep their cost low. See how it works. D

Having had ISDN and a home Lan, reality can get a little confusing. When you have 1 computer on an isdn. The user gets X amount of data. When you have 2 computers on an isdn, each user get 2/3rds X amount of data. You would like to assume it's half but it's not. You just get more efficient. When 1 computer downloads, it downloads, waits, downloads, waits.... When 2 computers download, 1 downloads, the other fills a buffer, then as soon as the first computer gets a pause the buffered requests kick in and download, causing the first to buffer... So when you add a whole lot of users to what you think is a small pipe they really don't see much slow down. If you look at your internet usage, let's say 2 gig/month. You dialed in at 50kbps. 50000/10(bytes/8baud+2startstopbits)*60(minute/second)*60(hour/minute)*24(day/hour)*31(day/month)=13392000000bytes/month =12.47gigabytes/month. Your real download speed is 16% or 8kbps. Thus you could have 6.25 equal users on that one modem and still download everything. T1=23*64kb or 29.44 times faster than your modem. 6.25*29.44 = 184 equal users. So you could have 184 users on 1 T1 with 2 gigabytes of download limit per month. Minuses- 8 hour days Pluses- Proxy server, internet limits, people adapt to maximize their life and will take odd hours if there is more self gain.