| Don't be confused about the difference | | | | F-bits (framing) 28 bits/ |
| between DS3 and T3 circuits. These terms are | | | | |
| really synonymous. Instead you should focus | | | | M-bits (multiframing) 3 bits/ |
| on what they can do for you...and the best | | | | |
| scenarios for application. | | | | C-bits (stuffing) 21 bits |
| | | | |
| Digital Signal (DS) is a system of | | | | X-bits (message) 2 bits/ |
| classifying digital circuits according to the | | | | |
| rate and format of the signal (DS) and the | | | | P-bits (parity) 2 bits/ |
| equipment providing the signals (T). DS and T | | | | |
| designations have come to be used | | | | Data bits between overhead bits 84 |
| synonymously so that DS1 implies T1, and DS3 | | | | |
| implies T3. | | | | A DS3 connection is comprised up of two |
| | | | monthly charges: the local loop and the port |
| A DS3 line (also known as a T-3) is an ultra | | | | charge. The local loop charge is the cost of |
| high-speed connection capable of transmitting | | | | the circuit provided by the Local Exchange |
| data at rates up to 45 Mbps. A DS3 line is | | | | Carrier (LEC) that allows DS3 access into the |
| equal to approximately 672 regular | | | | carrier's network. The loop charge is based |
| voice-grade telephone lines, which is fast | | | | on the distance from the customer's location |
| enough to transmit full-motion, real-time | | | | to the edge of the carrier's network; the |
| video, and very large databases over a busy | | | | farther the customer is from the network, the |
| network. A DS3 line is typically installed as | | | | more the loop will cost. Nearly every carrier |
| a major networking artery for large | | | | prices loops differently so it is in your |
| corporations and universities with | | | | best interest to price DS3 service with |
| high-volume network traffic. Other example | | | | several providers to ensure that you get the |
| applications include large call centers, | | | | best deal. |
| enterprise wide VoIP and IP PBX systems, | | | | |
| Internet service providers, research labs, | | | | DS Internet Access is the ideal solution for |
| video conference centers and software | | | | businesses that require high-bandwidth access |
| development companies. A DS3 is the second | | | | at a reduced price. Whether you host |
| fastest, non optical connection offered in | | | | high-traffic Web sites, support Web hosting |
| North America. A DS3 line is comprised of 28 | | | | or need high-capacity bandwidth on an |
| T1 lines, each operating at total signaling | | | | as-needed basis, there's a level of DS3 |
| rate of 1.544 Mbps. | | | | service (Full or fractional) that will meet |
| | | | your needs. Fractional to full DS3 or T3 |
| DS3 circuits provide businesses and Internet | | | | circuits run from speeds of 3 Mbps up to 45 |
| Service Providers (ISPs) with up to 45 Mb/s | | | | Mbps. |
| of dedicated Internet connectivity. This is | | | | |
| an ideal solution for users who have outgrown | | | | For customers that require more bandwidth |
| their T1 connections and are in search of | | | | than a T1 line can provide but do not yet |
| unlimited, high-capacity access. A DS3 line | | | | require the capacity of a full DS3 line, a |
| actually consists of 672 individual channels, | | | | fractional DS3 connection is the ideal |
| each of which supports 64 Kb/s. DS3 lines | | | | solution. A fractional DS3 is similar to a |
| are extremely high bandwidth connections into | | | | full DS(T)3, only with some of the channels |
| a carrier's backbone. They typically include | | | | turned off. This reduces the total monthly |
| SLAs (Service Level Agreements) that | | | | cost and provides additional capacity that |
| guarantee uptime and performance. | | | | can be turned up in a matter of days. |
| | | | Unfortunately, the DS3 (T) loop is still |
| The DS3 signal itself is composed of 28 DS1 | | | | required for this service. |
| signals and is constructed using a two-step | | | | |
| multiplexing process. First, the 28 DS1 | | | | If a full DS3 line is more bandwidth that you |
| signals are multiplexed into seven DS2 | | | | really need, it is also possible to get |
| signals. Second, the seven DS2 signals are | | | | Fractional DS3, which gives you a portion of |
| multiplexed into one DS3 signal. Each | | | | full DS3 bandwidth at a lower cost. Of |
| multiplexing step uses bit stuffing to handle | | | | course, DS3 is also available in multiples to |
| the different input frequencies. Overhead | | | | increase bandwidth, similar to bonded T1 |
| bits provide alignment, error checking, | | | | service. |
| in-band communications, and bit stuffing | | | | |
| control information. | | | | DS3 service can be deployed for a wide verity |
| | | | of applications. The most common uses are DS3 |
| Line rate: 44,736,000 b/s | | | | point-to-point, DS3 internet, DS3 frame |
| | | | relay, DS3 voice and DS3 VPN. The pricing for |
| Signals: 7 DS2 signals = 28 DS1 signals | | | | these connections varies widely depending on |
| | | | the carrier, location of service and the |
| Overhead bits: | | | | application for which the connection is being |
| | | | used. Visit DS3 Bandwidth to obtain current |
| 56 bits total/frame | | | | "real time" rate quotes for your location. |
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