3Com 10014298 manual Dynamic Lacp aggregation

Configuring Link Aggregation 45

Dynamic LACP aggregation

Dynamic LACP aggregation allows automatic adding/deleting by the system but prohibits manual configuration of users. Dynamic LACP aggregation can be established for a single port; this is called single port aggregation. LACP is enabled on dynamic aggregation ports. Only ports with the same speed, duplex mode and basic configuration and connected to the same device can be aggregated dynamically.

Only a defined number of ports can be supported in an aggregation group. If the ports in an aggregation group exceed the port quantity threshold for that group, the system will set some ports with smaller system IDs (system priority + system MAC address) and port IDs (port priority + port number) as selected ports and others as standby ports. If not, all member ports are selected ports. Both selected and standby ports can transceive LACP protocol, but standby ports cannot forward user service packets. Among the selected ports of an aggregation group, the one with the lowest port number serves as the master port for that group and the others are sub-ports.

In comparing system IDs, the system first compares system priority values; if they are equal, then it compares system MAC addresses. The smaller system ID is considered highest priority. Comparing port IDs works in the same way: the system first compares port priority values and then port numbers and the small port ID is considered highest priority. If the system ID changes from non-priority to priority, then the selected or standby state is determined by the port priority of the system. You can decide whether the port is selected or standby by setting system priority and port priority.

Load Sharing Link aggregation may be load balancing and non-load balancing. In general, the system only provides limited load balancing aggregation resources, so the system need to rationally allocate these resources among manual aggregation groups, static LACP aggregation groups, dynamic LACP aggregation groups and the aggregation groups including special ports which require hardware aggregation resources. The system will always allocate hardware aggregation resources to the aggregation groups with higher priority levels. When the load sharing aggregation resources are used up for existing aggregation groups, newly-created aggregation groups will be non-load sharing ones. The priority levels (in descending order) for allocating load sharing aggregation resources are as follows:

■Aggregation groups including special ports which require hardware aggregation resources

■Manual and static LACP aggregation groups

■Aggregation groups that probably reach the maximum rate after the resources are allocated to them

■Aggregation groups with the minimum master port numbers if they reach the equal rate with other groups after the resources are allocated to them

When aggregation groups of higher priority levels appear, the aggregation groups of lower priority levels release their hardware resources. For single-port aggregation groups, if they can transceive packets normally without occupying hardware resources, they shall not occupy the resources.