7-18 SmartSwitch 1800 4.0 User Guide, Rev 01Enable Outgoing Rate Controldetermines whether the rate parameters (CIR, BC , B E ) will be enforced.Enable Bandwidth Allocationdetermines whether bandwidth allocation (described on page 7-6) will be enforced.For Backup Use Only?determines whether all DLCIs on the port will be reserved exclusively as backups forother DLCIs in the same node. See "Configuring Frame Relay Backup Groups" onpage 7-22. If this parameter is set to Y, the port will remain disabled until needed forbackup.If configuring the port for backup use only, make sure no DLCIs on the porthave been configured on an IP, IPX, or LLC2 interface.Automatic DCEenables (if Y) automatic detection by the software of whether the port is a physicalDCE or DTE. This can be helpful in cases such as a connected backup CSU/DSU,which might be configured differently than the primary connection. The automaticDCE feature allows switchover to occur without reconfiguring the port.DLCI ParametersCommitted Information Rate (In/Out)(CIR) is the incoming or outgoing (depending on the parameter) data throughput thatthe network agrees to support under normal conditions. Outgoing throughput greaterthan CIR will be reduced to CIR if (a) a packet is received with the BECN (backwardexplicit congestion notification) bit set, and (b) Enable Outgoing Rate Control is Y.Committed Burst Size (In/Out)(B C ) is incoming or outgoing (depending on the parameter) the maximum amount ofdata that the network agrees to transfer under normal conditions within the time perioddefined by BC /CIR. Any data exceeding B C will have the Discard Eligibility (DE) bitturned on, and will be tracked by the SmartSwitch 1800 statistic DE/sec (*10).Turning on the DE bit will not automatically cause a packet to be discarded, but willtell the network which packets it can discard if traffic becomes too heavy.Excess Burst Size (In/Out)(B E) is the incoming or outgoing (depending on the parameter) maximum amount ofdata in excess of the Committed Burst Size that the network will attempt to transferduring the time interval used for the Committed Burst Size. Any outgoing dataexceeding this value will be buffered in the SmartSwitch 1800, and any incoming dataexceeding the value will be discarded.BECN Recovery Countis a method of controlling the rate of return to maximum traffic flow after it has beenreduced due to congestion. If a packet is received with the BECN (backward explicitcongestion notification) bit set, outgoing traffic will be throttled back to CIR, and theeffective value of B E will become 0 (limting traffic flow to the configured BC ). Fromthat point on, for each "n" packets (where "n" is the value of BECN Recovery Count)
