3Com 3C17300A Implementation Guide - Page 27

Aggregated Links 27 re-mapping occurs as soon as the Switch detects that a member link has failed - almost instantaneously. As a result, aggregated link configurations are extremely resilient and fault-tolerant. Figure 2 Dynamic Reassignment of Traffic Flows A Physical Link 2 Y A X B1 Y Z X X B2 X Physical Link 1 Aggregated Link B The key benefits of 802.3ad link aggregation are: ■ Automatic configuration - network management does not need to be used to manually aggregate links. ■ Rapid configuration and reconfiguration. ■ Compatibility - non-802.3ad devices can interoperate with a 802.3ad enabled devices. However, you will need to manually configure the aggregated links as LACP will not be able to automatically detect and form an aggregation. ■ The operation of 802.3ad can be configured and managed via network management. Implementing 802.3ad Aggregated Links LACP can be enabled or disabled on a per port basis. You can implement 802.3ad aggregated links in three ways: ■ Manual Aggregations - You can manually add and remove ports to and from an aggregated link via Web or CLI commands. However, if a port has LACP enabled, if a more appropriate or correct automatic membership is detected by LACP, it will override the manual configuration. For example, in Figure 3, if a port on Switch C is physically connected to Switch B, but you manually configure the port on Switch C to be a member of an aggregated link for Switch A in error, LACP (if it is enabled) will detect this and place the port in the aggregated link for Switch B, thus overriding the manual configuration.