User's Manual

12-1
Chapter 12 Port Channel Configuration
12.1 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 12-1 Port aggregation
As shown in the above, S1 is aggregated to a Port Channel, the bandwidth of this Port Channel is the total of
all the four ports. If traffic from S1 needs to be transferred to S2 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.
S1
S2