User's Manual

12-2
For Port Channel to work properly, member ports of the Port Channel must have the 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.
12.2 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.
The port aggregation is that multi-ports are aggregated to form an aggregation group, so as to implement the
out/in load balance in each member port of the aggregation group and provides the better reliability.