For standard narrowband communication, ISDN-PRI divides a T1 or E1 trunk as follows:
T1 trunks are divided into 23 information channels are 1 signaling channel
E1 trunks are divided into 30 information channels, 1 signaling channel, and 1 framing channel
Certain applications, like video conferencing, require greater bandwidth. You can combine several narrowband channels into one wideband channel to accommodate the extra bandwidth requirement. Communication Manager serves as a gateway to many types of high-bandwidth traffic. In addition, DS1 converters are used for wideband switching at remote locations.
Performed using one of the three allocation algorithms: fixed, flexible, or floating.
Fixed allocation — Provides contiguous-channel aggregation. The starting channel is constrained to a predetermined starting point. (Used only for H0, H11, and H12 calls.)
Flexible allocation — Allows a wideband call to occupy non-contiguous positions within a single T1 or E1 facility (NxDS0).
Floating allocation — Enforces contiguous-channel aggregation. The starting channel is not constrained to a predetermined starting point (NxDS0).
