DELL N3000 User Manual

Configuring Link Aggregation

From a system perspective, a LAG is treated just as a physical port, with the 

same configuration parameters for administrative enable/disable, spanning 

tree port priority, path cost as may be for any other physical port.

When members are added to a LAG, they are removed from all existing 

VLAN membership. When members are removed from a LAG they are added 

back to the VLANs that they were previously members of as per the 

configuration file. Note that a port’s VLAN membership can still be 

configured when it's a member of a LAG. However this configuration is only 

actually applied when the port leaves the LAG.
The LAG interface can be a member of a VLAN complying with IEEE 

802.1Q.

Spanning tree does not maintain state for members of a LAG, but does 

maintain state for the LAG interface. As far as STP is concerned, members of 

a LAG do not have individual link state. (Internally, the STP state of the LAG 

interface is replicated for the member links.)
When members are deleted from a LAG they become normal links, and 

spanning tree maintains their individual link state information.

Statistics are collected for LAGs in the same manner as they are collected for 

the physical ports, in addition to the statistics collected for individual 

members as per the 802.3ad MIB statistics.

Ports to be aggregated must be configured so that they are compatible with 

the link aggregation feature and with the partner switch to which they 

connect.
Ports to be added to a LAG must meet the following requirements:

• Interface must be a physical Ethernet link.
• Each member of the LAG must be running at the same speed and must be 

in full duplex mode.