Frame Relay Uni Sig Rate Adaptation

This attribute specifies whether closed-loop rate adaptation is in effect for SVCs on this interface. Rate adaptation is a feature that, in periods of congestion, adapts the rate at which the user is allowed to send data into the network to that which the network is able to handle at that time. This pro-active measure of handling congestion optimizes network resources by causing the ingress to discard frames that would otherwise be discarded in the network. If this attribute is set to on, then, at the onset of congestion, the excess information rate (EIR) is reduced to a very low rate. If congestion persists, then the allowed CIR is reduced geometrically by 25% of the current value at that time. The minimum to which CIR can be reduced is 1/16th (6.25%) of the provisioned value. As congestion alleviates, CIR is increased linearly by 6.25% of the provisioned value specified in committedInformationRate. If set to eirOnly, then rate adaptation will only apply to the excess information rate (EIR). At the onset of congestion, the allowed EIR is reduced by 25% of its provisioned value. If congestion persists, EIR is reduced geometrically by 25% of the current value at that time. As congestion alleviates, EIR is gradually increased linearly by 6.25% of the provisioned EIR. If set to cirProportionate, then rate adaptation will also only apply to the excess information rate (EIR). At the onset of congestion the initial allowed EIR is set to a multiple of the provisioned CIR. If congestion persists, the allowed EIR is reduced geometrically by 25% of the current value at that time. As congestion alleviates, EIR is gradually increased linearly by 6.25% of the provisioned EIR. Note that the allowed EIR may be set higher than the provisioned EIR, since it is calculated initially using another parameter, the provisioned CIR. If the allowed EIR at the moment is higher than the provisioned EIR, then the provisioned EIR is used instead. This attribute can only be turned on or eirOnly if rateEnforcement is turned on.