26Table 4 LACP prioritiesType Description RemarksSystem LACPpriorityUsed by two peer devices (or systems) to determine which one issuperior in link aggregation.In dynamic link aggregation, the system that has higher system LACPpriority sets the Selected state of member ports on its side first and thenthe system that has lower priority sets port state accordingly.The smaller thepriority value,the higher thepriority.Port aggregationpriorityDetermines the likelihood of a member port to be selected on a system.The higher port aggregation priority, the higher likelihood.3. LACP timeout intervalThe LACP timeout interval specifies how long a member port waits to receive LACPDUs from the peer port.If a local member port fails to receive LACPDUs from the peer within three times the LACP timeout interval,the member port assumes that the peer port has failed. You can configure the LACP timeout interval eitheras the short timeout interval (1 second) or long timeout interval (30 seconds).Link aggregation modesLink aggregation has two modes: dynamic and static. Dynamic link aggregation uses LACP and staticlink aggregation does not. Table 5 compares the two aggregation modes.Table 5 A comparison between static and dynamic aggregation modesAggregationmodeLACP status onmember ports Pros ConsStatic DisabledAggregation is stable. Theaggregation state of the memberports are not affected by the peerports.The member ports do not adjustthe aggregation state accordingto that of the peer ports. Theadministrator must manuallymaintain link aggregations.Dynamic EnabledThe administrator does not needto maintain link aggregations. Thepeer systems maintain theaggregation state of the memberports automatically.Aggregation is instable. Theaggregation state of memberports is susceptible to networkchanges.In a dynamic link aggregation group:• A Selected port can receive and send LACPDUs.• An Unselected port can receive and send LACPDUs only if it is up and have the same class-twoconfigurations as the aggregate interface.Aggregating links in static modeLACP is disabled on the member ports in a static aggregation group. You must manually maintain theaggregation state of the member ports.The static link aggregation procedure comprises:• Choosing a reference port• Setting the aggregation state of each member port
