| Click to Post a New Message!
Page | | [ 3 ] | | | |
| | |
|
Slow Response Time for Tractor Point
Ducati, I question your cable modem speeds.
As you may know the industry standard on cable modem speeds are 128kbps, 256kbps, 512kbps, and 768kbps. The next level available is called a T1 at a speed of 1.544mbps, which is not available in most cable installations. However, when available, a T1 connection can cost up to $1000 dollars per month and require a mult-year contract, compared to about $25 per month for a 512kbps.
T1 connections are considered high data capacity and are point to point fiber using a 10/100 MB ethernet. These are usually business data connections.
A T1 is equivalent to a DS-1 (telephone) and 28 DS-1 equals one 0C -1. This stands for optical carrier at a speed of 51.84mbps, which is now called a SONET (telephone) system.
Ducati, if I am wrong, and you actualy have a T1 connection, I would like to know more about it. I have a T1 at my office and rarely exceed 800kbps. This is a point-to-point fiber. I can ping my business office server at another location in 1ms.
A footnote to those who aren't familar with internet connections:
1. A basic connection is a dialup on a telephone line.
2. The next higher is a DSL connection provided by your telephone carrier.
3. Then you move up to a cable modem as I just discussed.
4. Beyond a cable modem is a point-to-point optical fiber connection called ethernet.
Dave
|
|
 Add Photo
Bookmarks: |
|
| |
|
Slow Response Time for Tractor Point
Interesting discussion,
I use a wireless converter to a point about a mile away, then a relay to a tower approx 8 miles away and then inputed to a T1 line (probably installed by Alexander G Bell and his helper what's his name).
My point is this site is about as quick as any other to me!
Detail of my results:
25ms hsipaccess1.dallas1.level3.net
35ms hsipaccess1.newyork1.level3.net
38.6ms hsipaccess1.seattle1.level3.net
Please comment at your pleasure!
|
|
Add Photo
Bookmarks: |
|
| |
|
Slow Response Time for Tractor Point
kyvette, your close, but not on target. 28 T1's ride on a T3 or what the carriers call an DS-3, not an OC-1. The common method of transporting a DS3 is over an OC-3, which is the smallest termination device they make. The next up would be an OC-12 which carries 12 DS-3's or split off into 6 DS-3's and 6 T1 breakout boxes, or 9 DS-3's and 3 T1 breakout boxes, or whats commonly referred to as Dmarks. The speed of a DS-3 is 44 Mbs, the speed you are referring to and the Sonet are the interoffice backbones of the carriers. In most situations with ISP's and T1 customers, what happens is the ISP orders a DS3 with the local telco, and that terminates from the closest CO to where they terminate the DS3. From there the ISP orders a DS1 to the customer and the telco will Mux the T1 onto the T3 at the ISP, from the CO it goes through the Telcos backbone, either over sonet, ds3, or in some cases directly onto copper. From the last Co to the customer, depending on distance, it leaves the CO and runs on copper. Rarely does it hit the customers prem with fiber, in those cases there is a lightspan that is located outside the customers location within the last mile and terminates over copper at that point. T1's are based on copper, T3s are based on fiber.
Now for cable systems, they can get as high as 10 meg downstream, but it is a shared system, meaning the more poeple downloading, the slower the connection will get, upstream is fixed at those speeds you posted. Cable systems use frequencies to transmit the internet data that ride along with the analog signals of the video stream, in most cases now, all the signals are moving to digital, so more bandwidth will be avaiable which will ease up the constraints of a shared system. The speeds which some people have seen who use cable are probably experiencing the shared bandwidth syndrome of too many users, since all shared service, whether its, dialup, cable, satalite, or wireless, always oversubscribe users on these systems, usually on a 4:1 ratio. Only those with a fixed T1 or T3 have full unshared bandwidth.
FYI, worked as a network engineer for an ISP for 7 years, and in fact gave a few SBC techs a lesson or two in T1 technology. 
Hope I didnt cause more confusion, and helped some to better understand how broadband works.
|
|
Add Photo
Bookmarks: |
|
| |
|
Slow Response Time for Tractor Point
kyvette,
The service is from Cablevision- Optimum online) they are known as one of the fastest providers. Its burstable like most modems and but it does fluctuate...please keep in mind we are not capped at 128Kbps, like most of the other providers. Benchmarks have been set from all test sites as well as results.
Sounds like your fiber connection isnt a true full Internet T1..You probably have your voice lines sharing the T1 connection (i.e Bundled service). You can get DSL with better speeds, and for a lot less money (if in the area).
Cable modem service is known for its burstable service and speeds, and certainly is superior in most cases over DSL.
I'm in the telcom & Integrator industry (lots and lots of experience) and sell ciruits domestically as well as Internationally...your definition of a T1 is a little off. Not all demarcs are fiber and actually most of them are over copper with a synchronous connection.
Ducati
|
|
Add Photo
Bookmarks: |
|
| |
|
Slow Response Time for Tractor Point
Ducati and Taheide,
I should have known that somewhere on this board there would be somebody with telecommunications experience and I have just enough to be dangerous.
A couple of comments. Taheide, I think we both agree a T1 is 1.544mbps and is equivalent to a DS-1. Twenty eight T1 and/or DS-1 equal 44.763mbps. My understanding, in communication tech language, a DS-1 is 24 non synchronous channels of 64kbps. The T1 is a more common industry standard and equates to the OC-1 as 44.763mbps + 7.104mbps overhead equaling the 51.840mbps.
Generally, for T1 connections a portion can be run over copper, usually, a twisted Cat-5. However, Cat-5 is for short runs with a 300 meter limitation. For higher capacity data transmission it requires point-to-point fiber.
Relating to cable modem speeds, I didn't realize these could be adjusted by the service provider and in a lot of cases you have a non synchronous connection, where the download speed maybe higher than the upload speed.
As I said previously I have a little experience with fiber and telecommunications, but apparently not enough. Thanks for your input. Dave
|
|
Add Photo
Bookmarks: |
|
| |
|
Slow Response Time for Tractor Point
Your good for the most part, except I think the overhead part you are thinking of is related to the voice portion from the early days when each channel needed a seperate carrier of 8kb for the encoding, but these days, most DS1's are Muxed onto DS3's and the "overhead" has been relegated to the actual devices that do the Multiplexing. As for the T1 cabling, it can run point to point over copper for many miles, in fact it can run from one location to another that is 50 miles away if needed. The limitation depending on what type of T1 is being installed, be it HDSL2, HDSL4, etc, the # being the type of wire it runs on. Lets take HDSL4, it runs over 2 pair of copper, with a limitation of 5000 feet, in between these limitations of the run there are what are called doublers or repeaters that boost the signal much in the same way a switch or hub does on an ethernet run. So on a full copper run of say 15,000 feet, there will be 2 pair of copper and 3 repeaters/doublers. One pair is the transmit tip and ring, the other is the recieve tip and ring. A T1 is a fully synchronis circuit, it can send and recieve at 1.54Mbps for a full duplex speed of ~3mbps. An HDSL2 runs over 1 pair of copper, and is also full duplex, it has a transmit and a receive wire, bit no tip and ring, instead its a fully digital signal that is encoded and decoded from the SmartJack to the first CO, or LightSpan. When working with SBC, I found they prefer the 4 wire over the 2 wire because if there are any issues with the copper the 2 wire tends to fail.
Here is a link for a more detailed write up on T1's.
http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci213096,00.html
Another link is below.
Link:
|
|
Add Photo
Bookmarks: |
|
| |
|
Slow Response Time for Tractor Point
Here is an ultimate link specifying what does what.
Kyvette, I think I see what you were saying, but I think you got the two confused. An OC1 is SONET, T1's are muxed onto SONET, but they are used for the Telcos backbone, so they can run many channels over a single strand of fiber easily, the overhead you are referring to is the clocking and VTs needed for DS1's to run over SONET. The majority of the overhead is from muxing the DS3 onto the OC1. In most cases though the end receiver, the ISP or customer runs the Mux off a DS3, not the SONET, only the Telcos do anything with the SONET, except in the rare cases of a major customer such as AOL, or maybe Motorola. In those cases they would purchase fiber from a carrier, called Dark Fiber and implement their own equipment.
Note: I edited the information after doing some further researh into SONET, I found there are other uses other than for the main backbone.
Link:
|
|
Add Photo
Bookmarks: |
|
| |
|
Slow Response Time for Tractor Point
Taheide,
Thanks for the info and web links, I will check them out. My exposure to T1's, SONET, etc is communications between electrical substations and SCADA dispatching centers.
SCADA stands for Supervisory Control And Data Acquisition. This is computer monitoring and control systems for the electric utility industry.
At present we use a communication protocol called DNP3 and communicate over a 24ct single mode fiber using 10/100mbps Ethernet. Some of our runs are home runs, where others access a SONET hub or a splice enclosure for transmission back to the dispatching center.
Have a Merry Christmas and thanks. Dave
|
|
Add Photo
Bookmarks: |
|
| |
|
Slow Response Time for Tractor Point
Sounds like fun . I have 7 years of internet experience, and now work on a different part of internet, VOIP. Today I go for my CCNA, so wish me luck!
A CCNA with a tractor, a dangerous combination, mowing at the speed of broadband!
|
|
Add Photo
Bookmarks: |
|
| |
|
Slow Response Time for Tractor Point
I have had DSL and now have cable. The cable is way faster then the DSL every was. The worst day for cable is still better then the best day for DSL.
|
|
Add Photo
Bookmarks: |
|
| |
|
Page | | [ 3 ] | | | |
Thread 102327 Filter by Poster:
1 | 2 | 1 | 4 | 1 | 1 | 2 | 3 | 2 | 7 | 1 | 3 | 2 | 1 | 9 | 1 |
|
()
Picture of the Day
RANCHER24
Unanswered Questions
Active Subjects
Hot Topics
Featured Suppliers
|
Gas Generator Weather Protecti
12-19-2004, 19:39 
Pics
Reply
Digg It 
Del.icio.us 
