H3C Technologies H3C S12500 Series Switches - Manual (Page 123)

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NOTE:
•
Any port attribute or class-two configuration change on a member port might change the aggregation
state and cause service interruption.
• A port that joins the static aggregation group after the Selected port limit has been reached will not be
placed in the selected state even if it otherwise should be. This is can prevent ongoing traffic on the
current Selected ports from being interrupted. You should avoid the situation, however, as it can cause
the aggregation state of a port to change after a reboot.
Aggregating links in dynamic mode
LACP is automatically enabled on all member ports in a dynamic aggregation group. The protocol
maintains the aggregation state of ports automatically.
Dynamic link aggregation comprises:
• Choosing a reference port
• Setting the aggregation state of each member port
Choosing a reference port
The local system (the actor) negotiates with the remote system (the partner) to choose a reference port as
follows:
1. Compare the system ID (comprising the system LACP priority and the system MAC address) of the
actor with that of the partner. The system with the lower LACP priority value is chosen. If they are
the same, compare the system MAC addresses. The system with the lower MAC address is chosen.
2. Compare the port IDs of the ports on the system with the smaller system ID. A port ID comprises a
port aggregation priority and a port number. First compare the port aggregation priorities. The
port with the lower aggregation priority value is chosen. If two ports have the same aggregation
priority, compare their port numbers. The port with the smaller port number is chosen. Thus, the
port with the lowest port ID is chosen as the reference port.
Setting the aggregation state of each member port
After the reference port is chosen, the system with the lower system ID sets the state of each member port
in the dynamic aggregation group on its side as shown in Figure 35 .