The committed information rate (specified in bits per second) is used to control the rate data is sent on the virtual circuit.
The CIR is set at subscription time in agreement with your network provider. The CIR is the amount of data guaranteed to be carried by the network during normal operating conditions. The virtual circuit can send data in excess of the CIR (bursting) as allowed by the Excess Information Rate (EIR).
When the CIR is set to zero then the SyncLink adapter sends data on the virtual circuit as fast as possible (up to the access port data rate) without regard for network congestion. If network congestion occurs, the data in excess of the CIR may be discarded. Any lost data should be retransmitted by the higher level protocols (IP, IPX, etc.). This is the default setting.
When the CIR is set to a non-zero value, the data rate for the PVC will be reduces to the CIR during network congestion. When no network congestion exists, data will be sent on the PVC in excess of the CIR as allowed by the EIR setting.