| DS-3 which stands for Digital Signal Level 3, equates | | | | installed as a major networking channel for large |
| to 28 T-1 lines or 44.736 million bits per second (roughly | | | | corporations or universities with high volume network |
| 43-45 Mbps upstream/downstream speeds). DS-3s | | | | traffic. This is an always-on, high-speed connection that |
| have enough bandwidth to allow very large database | | | | provides a dedicated, stable and reliable link to the |
| transferring over busy wide area networks and the | | | | Internet, and can support up to 500 or more computer |
| capability of handling 672 simultaneous voice | | | | users. |
| conversations. DS-3s typically run long haul over fiber | | | | If a full 45 Mbps DS-3 isn't quite necessary, then 'tiered' |
| optics and coax in the last mile, however there are | | | | and 'burstable' speeds are also an option. Tiered is |
| many exceptions to this. Also, because fiber is only | | | | more suitable for clients who expect their bandwidth |
| available in limited parts of the US (vs. copper), | | | | requirements to increase steadily and/or continually in |
| expensive build-outs are sometimes required for full | | | | the near future. Clients with other access such as T1 |
| DS-3 access. | | | | lines can rapidly and easily switch their bandwidth to a |
| In North America, DS-3 translates into T-3, which is the | | | | single Fractional-DS3. Burstable is a dedicated |
| equivalent of 28 T-1 channels, each operating at a total | | | | point-to-point circuit from a customer's premises to the |
| signaling rate of 1.544 Mbps. The 28 T-1s are | | | | telecommunication carrier's network operation center |
| multiplexed through an M13 ('Multiplex 1-to-3' multiplexer), | | | | (NOC). This service is priced in billing tiers of 3mbps |
| and 188 additional signaling and control bits are added | | | | increments from 3mbps to 45mbps. As a burstable |
| to each T-3 frame. As each frame is transmitted | | | | DS3 user, you always have the full bandwidth available |
| 8,000 times a second, the total T-3 signaling rate is | | | | over an unshared, non-fractional 45mbps digital leased |
| 44.736 Mbps. In a channelized application, T-3 supports | | | | line. |
| 672 channels, each of 64 Kbps. In the European | | | | Although anyone can purchase a burstable DS-3, this |
| hierarchy, a DS-3 is in the form of a E-3, which runs at | | | | type of connection can be expensive, sometimes |
| a total signaling rate of 34.368 Mbps, supports 480 | | | | costing as much as a full 45 Mbps connection (and |
| channels, and is the equivalent of 16 E-1s. | | | | usually only available for Internet connectivity, not as |
| If you're moving a DS-3 (or any other DS signal) | | | | Private Line or Point To Point- for which a full DS3 will |
| across continents, the standards of the target country | | | | be required). Burstable lines can often be found at their |
| rule. Channels get muxed and demuxed, with signaling | | | | lowest price within a collocation facility. At a collocation |
| conventions translated as well. For example: On the | | | | facility (or simply referred to as a "colo") many users |
| US side T-1s are in multiples of 24 x 64 Kbps circuits | | | | share a large OC-3 or OC-12 pipe. As a customer, you |
| (total 1.5 Mbps) and in the UK, it's 30 x 64 Kbps (total 2 | | | | will not have to pay for the fixed cost of such a large |
| Mbps). If you were to interconnect to the US at a | | | | pipe, but will have the benefit of being able to burst up |
| DS-3 level, you would not receive 28 T-1s with 6 spare | | | | to very high bandwidths if necessary. If you need the |
| channels- You would get multiples of 30 E/T-1s. As | | | | reliability of a large pipe fur bursty traffic but don't have |
| they arrived in the UK, they would be muxed and | | | | the capital, consider a colo. If you have a steady |
| demuxed, along with translated signaling conventions. | | | | volume and are consistent, you may consider keeping |
| Who uses DS-3s? Companies who host high traffic | | | | services 'in house' and going with a T-3/DS-3 |
| web sites, support web hosting, and need high | | | | connection. Whether you're considering a collocation |
| capacity bandwidth on an as-needed basis. Also | | | | facility or a T3 to the door, make sure you use a |
| universities/colleges, government offices, and high | | | | telecommunications broker to help guide you through |
| volume call centers. A full DS3 can accommodate | | | | the many providers and plans available. To view |
| many simultaneous users depending on the | | | | sample DS3 pricing now, please visit the author's free |
| requirements of the business. Generally a DS3 line is | | | | quote generator @ BandwidthSeek. |