PLANET WGSW-50040 - Manual (Page 74)

8-1
Chapter 8 Port Channel Configuration
8.1 Introduction to Port Channel
To understand Port Channel, Port Group should be introduced first. Port Group is a group of physical ports in
the configuration level; only physical ports in the Port Group can take part in link aggregation and become a
member port of a Port Channel. Logically, Port Group is not a port but a port sequence. Under certain
conditions, physical ports in a Port Group perform port aggregation to form a Port Channel that has all the
properties of a logical port, therefore it becomes an independent logical port. Port aggregation is a process of
logical abstraction to abstract a set of ports (port sequence) with the same properties to a logical port. Port
Channel is a collection of physical ports and used logically as one physical port. Port Channel can be used as
a normal port by the user, and can not only add network’s bandwidth, but also provide link backup. Port
aggregation is usually used when the switch is connected to routers, PCs or other switches.
Figure 8-1 Port aggregation
As shown in the above, SwitchA is aggregated to a Port Channel, the bandwidth of this Port Channel is the
total of all the four ports. If traffic from SwitchA needs to be transferred to SwitchB through the Port Channel,
traffic allocation calculation will be performed based on the source MAC address and the lowest bit of target
MAC address. The calculation result will decide which port to convey the traffic. If a port in Port Channel fails,
the other ports will undertake traffic of that port through a traffic allocation algorithm. This algorithm is carried
out by the hardware.
Switch offers two methods for configuring port aggregation: manual Port Channel creation and LACP (Link
Aggregation Control Protocol) dynamic Port Channel creation. Port aggregation can only be performed on
ports in full-duplex mode.
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, then their “Allowed VLAN” and “Native VLAN” property should also be
SwitchA
SwitchB