Ethernet Link Aggregation Configuration; Basic Concepts - HP 5820X series Configuration Manual

Ethernet link aggregation configuration

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
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across the member ports.
Improves link reliability. The member ports dynamically back up one another. When a member port
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fails, its traffic is switched to other member ports automatically.
As shown in
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 each other.
Figure 10 Diagram for Ethernet link aggregation

Basic concepts

Aggregation group, member port, aggregate interface
Link aggregation is implemented through link aggregation groups. An aggregation group is a group of
Ethernet interfaces aggregated 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.
When you create an aggregate interface, the switch 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.
Assign Layer 2 Ethernet interfaces only to a Layer 2 aggregation group.
The rate of an aggregate interface equals the total rate of its member ports in the 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
A member port in an aggregation group can be in either of the following aggregation states:
Selected: A selected port can forward user traffic.
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Unselected: An unselected port cannot forward user traffic.
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Figure 10, Device A and Device B are connected by three physical Ethernet links. These
"Aggregation states of member ports in an aggregation
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group."