Hello everyone,
Today, I will share the definitions and port status of static and dynamic LACP.
Static LACP
The static LACP aggregation is manually configured by the user, and the system is not allowed to automatically add or delete ports in the aggregation group. The aggregation group must contain at least one port. When the aggregation group has only one port, the port can only be deleted from the aggregation group by deleting the aggregation group.
The LACP protocol of the static aggregation port is in the enabled state. When a static aggregation group is deleted, its member ports will form one or more dynamic LACP aggregations and keep the LACP enabled. Users are forbidden to close the LACP protocol of the static aggregation port.
Port status in the static aggregation group
In a static aggregation group, the port may be in two states: selected or standby. Both the selected port and the standby port can send and receive the LACP protocol, but the standby port cannot forward user messages.
In a static aggregation group, the system sets the port in the selected or standby state according to the following principles:
1. The system selects the port with the highest priority in the selected state according to the priority order of port full-duplex/high rate, full-duplex/low rate, half-duplex/high rate, half-duplex/low rate, and the other ports are in the selected standby state.
2. The peer device connected to the smallest port in the selected state is different, or the port connected to the same peer device but in a different aggregation group will be in the standby state.
3. The ports cannot be aggregated together due to hardware limitations (such as cross-board aggregation), and the ports that cannot aggregate with the smallest port in the selected state will be in the standby state.
4. Ports that are different from the basic configuration of the smallest port in the selected state will be in the standby state.
5. Since the number of selected ports in the aggregation group that the device can support is limited, if the current number of member ports exceeds the maximum number of selected ports that the device can support, the system will select some ports as selected ports in the order of port numbers from small to large, others are standby ports.
Dynamic LACP
Dynamic LACP aggregation is an aggregation created/deleted automatically by the system, and users are not allowed to add or delete member ports in the dynamic LACP aggregation. Only ports with the same speed and duplex properties, connected to the same device, and the same basic configuration can be dynamically aggregated. Even if there is only one port, a dynamic aggregation can be created. At this time, it is a single-port aggregation. In dynamic aggregation, the LACP protocol of the port is enabled.
Port status in the dynamic aggregation group
In a dynamic aggregation group, the port may be in two states: selected or standby. Both the selected port and the standby port can send and receive the LACP protocol, but the standby port cannot forward user messages.
Since the maximum number of ports in the aggregation group that the device can support is limited, if the current number of member ports exceeds the maximum number of ports, the local system, and the peer system will negotiate, based on the port with the best device id. The size of the id determines the status of the port. The specific negotiation steps are as follows:
1. Compare the device id (system priority + system mac address). First compare the system priority, if the same, then compare the system mac address. The end with the smaller device id is considered superior.
2. Compare port id (port priority + port number). For each port on the end with the best device ID, the port priority is first compared, and if the priority is the same, the port number is compared. The port with the smaller port id is the selected port, and the remaining ports are standby ports.
3. In an aggregation group, the port with the smallest port number in the selected state is the main port of the aggregation group, and the other ports in the selected state are the member ports of the aggregation group.
Use occasion
When the bandwidth is tight, the bandwidth can be expanded to n times the original link through logical aggregation
In the case of dynamic backup of links, link aggregation can be configured to realize dynamic backup between each member port of the same aggregation group.
That is all I want to share with you! Thank you!
