Introduction1-233610-A2-GB91-90 July 1999Figure 1-5. Sample Diagnostic ConfigurationRate AdaptionRate adaption allows the DSU to support a low-speedapplication on a high-speed DDS circuit. When additionalbandwidth is required, the customer can reconfigure theDSU to a higher speed without requiring a new DDScircuit. Rate adaption is supported for both point-to-pointand multipoint configurations.To enable rate adaption, set the DSU’s PrtSp(Kbps)configuration option to any valid speed that is less thanthe DSU’s Rate(Kbps). The DSU performs rate adaptionwhenever the port speed is set to less than the DDS rate.(Refer to Table 6-5, DSU Configuration Options, inChapter 6 for further information.)Aggregate SwitchingAggregate Switching provides an additional mode ofdial backup. When Aggregate Switching (AggrSwitch) isenabled, the DSU provides its internal aggregate datastream, including diagnostics and framing on the alternateV.35 or EIA-232-D interface of Port 1. Aggregate data isthen switched or bridged with the data on the DDS line.This aggregate port can be cabled to a TDM circuit cardconfigured for digital bridge and to external dial backupdevices, such as DBM-Ss.There are four types of aggregate switching dialbackup configurations:• Point-to-point (single port)• Multipoint (single port)• TDM• MCMPDuring aggregate switching, commands addressed tothe tributary DSU and DBM are automatically routed overthe aggregate port through the backup circuits. If a dialbackup is active, Change or Display Options commandsshould be addressed to the tributary DBM via the controlDBM-V, DBM-S, or DBM-D.For further explanation of the TDM and MCMPconfigurations, order the COMSPHERE 3600 Series DataService Units, Models 3610 and 3611, Time DivisionMultiplexer, Multichannel Multipoint, and Digital BridgeOptions, Applications Guide. Single-port aggregateswitching configurations are discussed in the followingparagraphs.
