Cisco 350 Series Administration Manual page 222

Port Management
Link Aggregation
NOTE
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Cisco 350, 350X and 550X Series Managed Switches, Firmware Release 2.4, ver 0.4
However, there are cases when one link partner is temporarily not configured for LACP. One
example for such case is when the link partner is on a device, which is in the process of
receiving its configuration using the auto-config protocol. This device's ports are not yet
configured to LACP. If the LAG link cannot come up, the device cannot ever become
configured. A similar case occurs with dual-NIC network-boot computers (e.g. PXE), which
receive their LAG configuration only after they bootup.
When several LACP-configured ports are configured, and the link comes up in one or more
ports but there are no LACP responses from the link partner for those ports, the first port that
had link up is added to the LACP LAG and becomes active (the other ports become non-
candidates). In this way, the neighbor device can, for example, get its IP Address using DHCP
and get its configuration using auto-configuration.
LACP Settings
Use the LACP page to configure the candidate ports for the LAG and to configure the LACP
parameters per port.
With all factors equal, when the LAG is configured with more candidate ports than the
maximum number of active ports allowed (8), the device selects ports as active from the
dynamic LAG on the device that has the highest priority.
The LACP setting is irrelevant on ports that are not members of a dynamic LAG.
To define the LACP settings:
Click Port Management > Link Aggregation > LACP.
Enter the LACP System Priority.
Select a port, and click Edit.
Enter the values for the following fields:
• Port—Select the port number to which timeout and priority values are assigned.
• LACP Port Priority—Enter the LACP priority value for the port.
• LACP Timeout—Time interval between the sending and receiving of consecutive
LACP PDUs. Select the periodic transmissions of LACP PDUs, which occur at either a
Long or Short transmission speed, depending upon the expressed LACP timeout
preference.
Click Apply. The Running Configuration file is updated.
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