Guidelines for Monitoring High-Gigabit Port ChannelsKeep the following points in mind when you activate and examine the utilization and working-efficiencyof backplane high-Gigabit Ethernet port channels as trunk groups:• By default, the capability to monitor the traffic utilization and distribution of high-Gigabit Ethernettrunk groups is disabled.• Each NPU unit in each line card (or control processor card) can contain multiple trunk groups (high-Gigabit port channels). The interface specifier convention for hg-port-channel is slotId/npuUnitId/localPortChannelId, which denotes the slot, NPU, and the port channel identifiers.• For Z9000, slotId (stack unitId) is constant and does not vary. NpuUnitId ranges from 0-5 and localportChannelId ranges from 0-0 for leaf NpuUnits and 0-3 for spine NpuUnits.• Link-bundle monitoring starts if monitoring is enabled for the bundle whose egress utilization exceedsa threshold. This behavior is required if you want to view the utilization alarms only when theutilization levels are high. At low utilization levels, it is possible that there are only one or twosignificant flows that are causing unevenness. Such an imbalanced traffic flow is not critical orindicative of a problem. The hiGig link bundle trigger threshold is a system-wide or a global setting forthe device.• If you enabled the generation of SNMP traps, syslogs and traps are transmitted when an unevendistribution is observed. Another syslog and trap is generated when the unevenness is cleared.• Link bundle utilization is calculated as the bandwidth-weighted mean utilization of all links in a bundle(calculated as [total bandwidth of all links / total bytes-per-sec of all links]). This calculation isperformed only on those links that are up on their operational status.• The rate interval for polling the traffic statistics for member links of the high-Gigabit port channelmust be configured. The default hiGig stats polling interval is 15 seconds. This interval cannot beconfigured per high-Gigabit port channel and is applicable for all of the high-Gigabit port channels onthe system.• The threshold value identifies when to start the link bundle utilization calculation trigger (default of 60percent). When overall utilization (mean) is below this value, link bundle distribution unevenness is notreported.• If unevenness is observed over three consecutive measurements, an alarm event is generated. TherateInterval for Hg stats polling (default 15 seconds) determines the time interval between twomeasurements. Alarm clear is sent when evenness is observed for three successive rate intervals. Ifindividual link utilization information is not available for a given timestamp, link bundle utilization isnot calculated at that timestamp. The previous known record shall be used for the alarm calculation.• Turning on and off the link bundle monitoring is performed at a high-Gigabit Ethernet port-channellevel configuration.• The difference of utilization % between the high-used link and low-used link is used to determine thealarm condition. The alarm trigger reporting is based on the same algorithm used for link bundlemonitoring on LAG/ECMP. The alarm reporting is triggered when the configured threshold hascrossed for a given bundle. Now, if the delta utilization is beyond 10%, an alarm is raised. The alarmcondition remains active until all interface utilizations are within the band or until the overall utilizationgoes below the trigger threshold. An alarm is not raised or cleared instantaneouslyLink Aggregation Control Protocol (LACP) 443
