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A T1 is considered to be a dedicated T1 when it carries only a single service type. This "single service type" could be voice only, 56kb data only, 64 KB data only, and 256kb data only, or even a single 1.544Mhz ISP access line. Consider a dedicated T1 line to be the opposite of integrated T1 access, which combines dissimilar service types onto a single T1 for access. Typical Examples (each example depicts a full T1):
The term T1 dedicated line has also been used to describe a T1 carrying service to only a single location. Considering that most applications refer to a T1 being an "access T1", the customer end is certainly a single location, but the far end of each of the services carried by the T1 access facility could be quite diverse. For instance, a single dedicated T1's facility is used for access to ABC Company's Detroit location. The T1 dedicated is comprised of 6 x 256kb data circuits with each circuit terminating to one of ABC's 6 regional offices. In this case, the T1 is dedicated to the access facility between the ABC Detroit location and the carrier's location where each of the 256kb circuits will be de-multiplexed and re-mapped towards their final destinations. Framing and Line Coding. Since dedicated T1s can carry voice or data, either format is possible. However, since ESF/B8ZS is a more robust format, and allows non-intrusive performance monitoring, it is strongly suggested that the T1 access facility be provisioned using ESF/B8ZS framing and line coding. The first part, ESF, refers to Extended Super-Framing , which allows for a single 8kb channel for control of the entire T1 and is a requirement for services greater than 56kb in speed. B8ZS refers to Binary Eight, Zero Suppression. This line coding option allows for extended streams of zeros without losing timing on the T1 facility.
ESF/B8ZS T1s also have the benefit of ESF monitoring, which allows the carrier to setup ESFMUs (monitoring units) to watch the performance of the T1 itself without disrupting the services carried by the T1. ESFMUs track performance using the 8kb ESF channel for statistics. |
Dedicated T1
