3Com® VCX V7111 VoIP Gateway User Guide 357Third-Party Performance Monitoring MeasurementsPerformance measurements are available for a third-party performance monitoring systemthrough an SNMP interface. These measurements can be polled at scheduled intervals byan external poller or utility in a media server or other off-device system.The device provides two types of performance measurements: Gauges: Gauges represent the current state of activities on the device. Gauges, unlikecounters, can decrease in value, and like counters, can increase. The value of a gauge isthe current value or a snapshot of the current activity on the device. Counters: Counters always increase in value and are cumulative. Counters, unlikegauges, never decrease in value unless the off-device system is reset, the counters arethen zeroed.Performance measurements are provided by several proprietary MIBs that are located underthe performance sub tree:iso(1).org(3).dod(6).internet(1).private(4).enterprises(1).3Com(5003).acPerformance(10).Two formats of performance monitoring MIBs are available: Old format (obsolete as of version 4.6):Each MIB is composed of a list of single MIB objects, each relates to a separate attributewithin a gauge or a counter. All counters and gauges provide the current time value only. acPerfMediaGateway - a generic-type of PM MIB that covers: Control protocol RTP stream System packets statistics acPerfMediaServices - Media services devices specific performance MIB. acPerfH323SIPGateway – holds statistics on Tel to IP and vice versa. New format:The following MIBs feature an identical structure. Each includes two major sub-trees. Configuration sub tree – enables configuration of general attributes of the MIB andspecific attributes of the monitored objects. Data sub treeThe monitoring results are presented in tables. Each table includes one or two indices. Whenthere are two indices, the first index is a sub-set in the table (for example, trunk number) andthe second (or a single where there is only one) index represents the interval number(present - 0, previous - 1 and the one before - 2).
