H3C Technologies H3C WX3000E Series Wireless Switches - Manual (Page 49)

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Configuring Ethernet link aggregation
Support of the H3C WX series access controllers for the Ethernet link aggregation feature may vary by
device model. For more information, see About the WX Series Access Controllers Configuration Guides.
Overview
Ethernet link aggregation, or simply link aggregation, combines multiple physical Ethernet ports into one
logical link, called an aggregate link. Link aggregation delivers the following benefits:
• Increases bandwidth beyond the limits of any single link. In an aggregate link, traffic is distributed
across the member ports.
• Improves link reliability. The member ports dynamically back up one another. When a member port
fails, its traffic is automatically switched to other member ports.
As shown in Figure 10 , Device A and Device B are connected by three physical Ethernet links. These
physical Ethernet links are combined into an aggregate link, Link Aggregation 1. The bandwidth of this
aggregate link is as high as the total bandwidth of these three physical Ethernet links. At the same time,
the three Ethernet links back up one another.
Figure 10 Diagram for Ethernet link aggregation
Basic concepts
Aggregation group, member port, and aggregate interface
Link aggregation is implemented through link aggregation groups. An aggregation group is a group of
Ethernet interfaces combined together, which are called member ports of the aggregation group. For
each aggregation group, a logical interface, called an aggregate interface, is created. To an upper
layer entity that uses the link aggregation service, a link aggregation group looks like a single logical link
and data traffic is transmitted through the aggregate interface.
Aggregate interfaces are bridge-aggregation (BAGG) interfaces, also called Layer 2 aggregate
interfaces. When you create an aggregate interface, the device automatically creates an aggregation
group of the same type and number as the aggregate interface. For example, when you create interface
Bridge-Aggregation 1, Layer 2 aggregation group 1 is created.
NOTE:
The rate of an aggregate interface equals the total rate of its member ports in Selected state, and its duplex
mode is the same as the selected member ports. For more information about the states of member ports in
an aggregation group, see " Aggregation states of member ports in an aggregation group ."
Aggregation states of member ports in an aggregation group
A member port in an aggregation group can be in either of the following aggregation states: