Operation Manual – Link Aggregation
H3C S5100-SI/EI Series Ethernet Switches
Chapter 1 Link Aggregation Configuration
1-5
Besides multiple-port aggregation groups, the system is also able to create single-port
aggregation groups, each of which contains only one port. LACP is enabled on the
member ports of dynamic aggregation groups.
II. Port status of dynamic aggregation group
A port in a dynamic aggregation group can be in one of the two states: selected and
unselected.
z
Both the selected and the unselected ports can receive/transmit LACP protocol
packets;
z
The selected ports can receive/transmit user service packets, but the unselected
ports cannot.
z
In a dynamic aggregation group, the selected port with the smallest port number
serves as the master port of the group, and other selected ports serve as member
ports of the group.
There is a limit on the number of selected ports in an aggregation group. Therefore, if
the number of the member ports that can be set as selected ports in an aggregation
group exceeds the maximum number supported by the device, the system will
negotiate with its peer end, to determine the states of the member ports according to
the port IDs of the preferred device (that is, the device with smaller system ID). The
following is the negotiation procedure:
1) Compare device IDs (system pr system MAC address) between the two
parties. First compare the two system priorities, then the two system MAC
addresses if the system priorities are equal. The device with smaller device ID will
be considered as the preferred one.
2) Compare port IDs (port pr port number) on the preferred device. The
comparison between two port IDs is as follows: First compare the two port
priorities, then the two port numbers if the two port priorities are equal; the port
with the smallest port ID is the selected port and the left ports are unselected ports.
Note:
For an aggregation group:
z
When the rate or duplex mode of a port in the aggregation group changes, packet
loss may occur on this port;
z
When the rate of a port decreases, if the port belongs to a manual or static LACP
aggregation group, the port will be switched to the unselected state; if the port
belongs to a dynamic LACP aggregation group, deaggregation will occur on the
port.
