Operation Manual – Link AggregationH3C S7500 Series Ethernet Switches Chapter 1 Link Aggregation Configuration1-5II. Port status of dynamic aggregation groupA port in a dynamic aggregation group can be in one of the two states: selected orstandby. In a dynamic aggregation group, both the selected and the standby ports cantransceive LACP protocol packets; however, the standby ports cannot forward userpackets.There is a limit on the number of selected ports in an aggregation group. Therefore, ifthe number of the member ports in an aggregation group exceeds the maximumnumber supported by the device, the system will negotiate with its peer end, todetermine the states of the member ports according to the IDs of ports of the preferreddevice (that is, the device with smaller system ID). The following is the negotiationprocedure:1) Compare device IDs (system priority + system MAC address) between the twoparties. First compare the system priority of the two devices. If the systempriorities are equal, compare the MAC address of the two systems. The devicewith smaller device ID will be considered as the preferred one.2) Compare port IDs (port priority + port number) on the preferred device. Thecomparison between two port IDs is as follows: First compare the two portpriorities, then the two port numbers if the two port priorities are equal; the portwith smaller port ID is a selected port and the other port is a standby port.In an aggregation group, the selected port with the minimum port number serves as themaster port of the group, and other selected ports serve as member ports of the group.Note:z The down ports in a static aggregation group or dynamic aggregation group arestandby ports, which is different in manual aggregation groups.z For the restriction of LPU types on link aggregation, refer to Table 1-2 and Table1-3.1.1.7 Restriction of LPU types on Link AggregationTable 1-1 lists link aggregation types and related descriptions.Note:Type-A LPUs include the following specifications: LS81FT48A, LS81FM24A,LS81FS24A, LS81GB8UA and LS81GT8UA.
