Operation Manual – Link AggregationH3C S3100 Series Ethernet Switches Chapter 1 Link Aggregation Configuration1-4z The system sets the ports with basic port configuration different from that of themaster port to unselected state.z There is a limit on the number of selected ports in an aggregation group. Therefore,if the number of the selected ports in an aggregation group exceeds the maximumnumber supported by the device, those with lower port numbers operate as theselected ports, and others as unselected ports.1.2.3 Dynamic LACP Aggregation GroupI. Introduction to dynamic LACP aggregation groupA dynamic LACP aggregation group is automatically created and removed by thesystem. Users cannot add/remove ports to/from it. Ports can be aggregated into adynamic aggregation group only when they are connected to the same peer device andhave the same speed, duplex mode, and basic configurations, and so are/do their peerports.Besides multiple-port aggregation groups, the system is also able to create single-portaggregation groups, each of which contains only one port. LACP is enabled on themember ports of dynamic aggregation groups.II. Port status of dynamic aggregation groupA port in a dynamic aggregation group can be in one of the two states: selected andunselected.z Both the selected and the unselected ports can receive/transmit LACP protocolpackets;z The selected ports can receive/transmit user service packets, but the unselectedports cannot.z In a dynamic aggregation group, the selected port with the smallest port numberserves as the master port of the group, and other selected ports serve as memberports of the group.There is a limit on the number of selected ports in an aggregation group. Therefore, ifthe number of the member ports that can be set as selected ports in an aggregationgroup exceeds the maximum number supported by the device, the system willnegotiate with its peer end, to determine the states of the member ports according tothe port IDs of the preferred device (that is, the device with smaller system ID). Thefollowing is the negotiation procedure:1) Compare device IDs (system priority + system MAC address) between the twoparties. First compare the two system priorities, then the two system MACaddresses if the system priorities are equal. The device with smaller device ID willbe 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 port
