PDF user manual for CopperEdge 150

A definition for the commitment interval has been establishedby CCITT and adopted by ANSI. The actual value will depend onthe settings of CIR, bcMax and be. For details on calculating T c ,refer to the Throughput object in the frCircuitTable in the CopperEdge150 CopperCraft Reference and MIB Definitions manual.Note that while the values of bcMax and BE remain constant overtime, the values of CIR and Access Rate appear as slopes. This isbecause bcMax and BE are expressed as absolute values (fixednumber of bits transmitted over the commitment-interval period),while CIR and Access Rate are expressed in bits per second.Setting CIR Parameters for Frame Relay PVCsBy default, the CIR setting on newly created WAN PVCs is zero.The default value of bcMax is also zero. In this case, ExcessBurstautomatically assumes the value of the Speed object in the IfTable.Thus, Speed in this instance may be considered as synonymouswith Access Rate as shown in the preceding illustration.1 2 7 (Congestion management parameters (CIR, bcMax, and BE) are notconfigurable for DSL VCs. Since there is no enforcement of CIR on thereceive side of WAN VCs, bandwidth commitments cannot be assignedor honored on the transmit side of the corresponding DSL VCs.With the factory default settings, every frame is technically discard-eligible.But, as frames will not normally be discarded unlessthe Access Rate is exceeded, the default scenariorepresents the most conservative situation.If you decide to configure the congestion-management parametersto a value other than the default, then we recommend thatyou first agree upon appropriate values for CIR, bcMax and BEwith your network provider.To set the information commitment parameters, all three of therelevant objects must be set as part of the same command toensure that all three are simultaneously applied. For example:CRAFT> set frcircuit [1.2.1.101] throughput=n1committedburst=n2 excessburst=n3Where:n1 is the Throughput value in bits per secondn2 is the size of the maximum committed burst in bitsn3 is the size of the ExcessBurst credit in bitsFor more information about throughput management and thetools available to monitor congestion on your Frame Relaylinks, see frCircuitTable in the CopperEdge 150 CopperCraftReference and MIB Definitions manual.&KDSWHU5RXWLQJ)RUZDUGLQJ0DQDJLQJ/LQNV