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Chapter 5 Port Channel Configuration
5.1 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.
Fig 5-1 Port aggregation
As shown in the above figure2-1,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.
ES4700 series offers 2 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.
SwitchA
SwitchB
