1-2
z
Selected: a selected port can forward user traffic.
z
Unselected: an unselected port cannot forward user traffic.
The rate of an aggregate interface is the sum of the selected member ports’ rates. The duplex mode of
an aggregate interface is consistent with that of the selected member ports. Note that all selected
member ports use the same duplex mode.
For how the state of a member port is determined, refer to
Static aggregation mode
and
Dynamic
aggregation mode
.
LACP protocol
The Link Aggregation Control Protocol (LACP) is defined in IEEE 802.3ad. It uses link aggregation
control protocol data units (LACPDUs) for information exchange between LACP-enabled devices.
LACP is automatically enabled on interfaces in a dynamic aggregation group. For information about
dynamic aggregation groups, refer to
Dynamic aggregation mode
. An LACP-enabled interface sends
LACPDUs to notify the remote system (the partner) of its system LACP priority, system MAC address,
LACP port priority, port number, and operational key. Upon receiving an LACPDU, the partner
compares the received information with the information received on other interfaces to determine the
interfaces that can operate as selected interfaces. This allows the two systems to reach an agreement
on which link aggregation member ports should be placed in selected state.
Operational key
When aggregating ports, link aggregation control automatically assigns each port an operational key
based on the port rate and duplex mode.
In an aggregation group, all selected ports are assigned the same operational key.
Class-two configurations
The contents of class-two configurations are listed in
Table 1-1
. In an aggregation group, a member port
different from the aggregate interface in the class-two configurations cannot be a selected port.
Table 1-1
Class-two configurations
Type
Considerations
Port isolation
Whether a port has joined an isolation group
QinQ
QinQ enable state (enable/disable), TPID values in VLAN tags, outer
VLAN tags to be added, inner-to-outer VLAN priority mappings,
inner-to-outer VLAN tag mappings, inner VLAN ID substitution mappings
VLAN
Permitted VLAN IDs, default VLAN, link type (trunk, hybrid, or access), IP
subnet-based VLAN configuration, protocol-based VLAN configuration,
tag mode
MAC address learning
MAC address learning capability, MAC address learning limit, forwarding
of frames with unknown destination MAC addresses after the upper limit
of the MAC address table is reached
