Constant bit rate
Constant bit rate (CBR) is an ATM service category that supports fixed bandwidth. A CBR virtual circuit (VC) provides a constant cell stream with minimal delay and jitter across the network. The information flow that makes the best use of a CBR connection is one with a constant, continuous data stream and sensitive to delay variations and data loss. CBR is the supreme ATM service category. The guarantees are such that—for all intents and purposes—the bandwidth is blocked out of the network for this traffic.
Business-critical corporate traffic is a common application for CBR service. The IT manager pays the premium for this class of service, even though the traffic profile might not be constant or delay sensitive. The premium is worth the guarantees. Uncompressed, circuit-oriented voice and video traffic are the classic applications for CBR service. These applications are constant rate, delay sensitive, and loss sensitive. A CBR VC can also be used to support circuit emulation service (CES).
- Available bit rate (ABR)
- Guaranteed frame rate (GFR)
- Unspecified bit rate (UBR)
- Variable bit rate (VBR)
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