Committed Information Rate (CIR)

In frame relay networks, a committed information rate (CIR) is a bandwidth (expressed in bits per second) associated with a logical connection in a permanent virtual circuit (PVC). Frame relay networks are digital networks in which different logical connections share the same physical path, and some logical connections are given higher bandwidths than others.

For example, a connection conveying a high proportion of video signals (which require a high bandwidth) could be set up for certain workstations in a company (or on a larger network) and other connections requiring less bandwidth could be set up for all other workstations. Using statistical multiplexing, frame relay assemblers and disassemblers (FRADs), the devices that interconnect to the frame relay network, manage the logical connections so that, for example, those with the video signals (and higher CIRs) get more use of the paths. Because the CIR is defined in software, the network's mix of traffic bandwidths can be redefined in a relatively short amount of time.

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