SNR S2989G-8TX [88/553] Brief introduction to lacp

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2-24

S2989G-24TX Operation Manual Chapter 2 Layer 2 services

Configuration

same properties as follows:

 All ports are in full-duplex mode.

 All Ports are of the same speed.

 All ports are Access ports and belong to the same VLAN or are all TRUNK ports, or

are all Hybrid ports.

 If the ports are all TRUNK ports or Hybrid ports, then their “Allowed VLAN” and

“Native VLAN” property should also be the same.

If Port Channel is configured manually or dynamically on switch, the system will

automatically set the port with the smallest number to be Master Port of the Port Channel.

If the spanning tree function is enabled in the switch, the spanning tree protocol will regard

Port Channel as a logical port and send BPDU frames via the master port.

Port aggregation is closely related with switch hardware. Switch allow physical port

aggregation of any two switches, maximum 128 groups and 8 ports in each port group are

supported.

Once ports are aggregated, they can be used as a normal port. Switch have a built-in

aggregation interface configuration mode, the user can perform related configuration in

this mode just like in the VLAN and physical interface configuration mode.

2.6.2

Brief Introduction to LACP

LACP (Link Aggregation Control Protocol) is a kind of protocol based on

IEEE802.3ad standard to implement the link dynamic aggregation. LACP protocol uses

LACPDU (Link Aggregation Control Protocol Data Unit) to exchange the information with

the other end.

After LACP protocol of the port is enabled, this port will send LACPDU to the other

end to notify the system priority, the MAC address of the system, the priority of the port,

the port ID and the operation Key. After the other end receives the information, the

information is compared with the saving information of other ports to select the port which

can be aggregated, accordingly, both sides can reach an agreement about the ports join

or exit the dynamic aggregation group.

The operation Key is created by LACP protocol according to the combination of

configuration (speed, duplex, basic configuration, management Key) of the ports to be

aggregated.

After the dynamic aggregation port enables LACP protocol, the management Key is 0

by default. After the static aggregation port enables LACP, the management Key of the

port is the same with the ID of the aggregation group.

For the dynamic aggregation group, the members of the same group have the same

operation Key, for the static aggregation group, the ports of Active have the same

operation Key.