Huawei AR530 series Configuration Manual page 46

Huawei AR530&AR550 Series Industrial Switch Routers
Configuration Guide - Ethernet Switching
Figure 2-1 Eth-Trunk networking
The link aggregation interface can be used as a common Ethernet interface to implement routing
protocols and other services. Unlike a common Ethernet interface, the link aggregation interface
needs to select one or more member interfaces to forward traffic.
Link aggregation concepts are described as follows:
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Issue 01 (2014-11-30)
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Link aggregation, link aggregation group (LAG), and link aggregation interface
Link aggregation technology bundles a group of physical interfaces into a logical interface
to increase bandwidth and improve reliability.
An LAG is the logical link bundled by many Ethernet links.
Each LAG corresponds to a logical interface, that is, link aggregation interface or Eth-
Trunk.
Member interface and member link
The interfaces that constitute an Eth-Trunk are member interfaces. A link corresponding
to a member interface is a member link.
Active and inactive interfaces and links
There are two types of interfaces in an LAG: active and inactive interfaces. The interface
that forwards data is called the active interface, while the interface that does not forward
data is called the inactive interface.
The link connected to an active interface is the active link, whereas the link connected to
an inactive interface is the inactive link.
Upper threshold for the number of active interfaces
When the number of active interfaces reaches this threshold, the bandwidth of the Eth-
Trunk will not increase even if more member links go Up. This guarantees high network
reliability. When the number of active member interfaces reaches the upper threshold,
additional active member interfaces go Down.
For example, 8 trouble-free member links are bundled into a trunk link, each link provides
the bandwidth of 1 Gbit/s, and the trunk link needs to provide a maximum of 5 Gbit/s
bandwidth. You can set the maximum number of Up member links to 5 or larger. The
remaining unselected links in Up state automatically enter the backup state, improving
reliability.
NOTE
The upper threshold for the number of active interfaces is inapplicable to the manual load balancing
mode. For details about the manual load balancing mode, see
Load Balancing Mode.
Lower threshold for the number of active interfaces
When the number of active interfaces falls below the lower threshold, the Eth-Trunk goes
Down. This guarantees the minimum available bandwidth for the Eth-Trunk.
For example, if the Eth-Trunk is required to provide a minimum bandwidth of 2 Gbit/s and
each member link's bandwidth is 1 Gbit/s, the lower threshold must be set to 2 or larger.
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Eth-Trunk
2 Link Aggregation Configuration
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2.2.3 Link Aggregation in Manual
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