Cisco SG220-26P - Configuring LACP

Port Management
Configuring Link Aggregation
Cisco 220 Series Smart Switches Administration Guide Release 1.1.0.x 119
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STEP 4 Click Apply. The LAG settings are defined, and the Running Configuration is
updated.
Configuring LACP
A dynamic LAG is LACP-enabled, and LACP runs on every candidate port defined
in the LAG.
LACP Priority and Rules
LACP system priority and LACP port priority are both used to determine which
candidate ports become active member ports in a dynamic LAG.
The selected candidate ports of the LAG are all connected to the same remote
device. Both the local and remote switches have a LACP system priority.
The following algorithm is used to determine whether LACP port priorities are
taken from the local or remote device: the local LACP System Priority is compared
to the remote LACP System Priority. The device with the lowest priority controls
candidate port selection to the LAG. If both priorities are the same, the local and
remote MAC addresses are compared. The priority of the device with the lowest
MAC address controls candidate port selection to the LAG.
A dynamic LAG can have up to 16 Ethernet ports of the same type. Up to eight
ports can be active, and up to eight ports can be in standby mode. When there are
more than eight ports in the dynamic LAG, the switch on the controlling end of the
link uses port priorities to determine which ports are bundled into the LAG and
which ports are put in hot-standby mode. Port priorities on the other device (the
non-controlling end of the link) are ignored.
The following are additional rules used to select the active or standby ports in a
dynamic LACP:
• Any link operating at a different speed from the highest-speed active
member or operating at half-duplex becomes standby. All the active ports
in a dynamic LAG operate at the same baud rate.
• If the port LACP priority of the link is lower than that of the currently active
link members, and the number of active members is already at the
maximum number, the link becomes inactive, and placed in standby mode.