2.1 Introduction to Link Aggregation
This section describes definition and purpose of link aggregation.
Definition
Ethernet link aggregation, also called Eth-Trunk, bundles multiple physical links to form a
logical link to increase link bandwidth. The bundled links back up each other, increasing
reliability.
Purpose
As the network scale expands increasingly, users propose increasingly high requirements on
Ethernet backbone network bandwidth and reliability. Originally, to increase the bandwidth,
users use high-speed cards or devices supporting high-speed interface cards to replace old
interface cards or devices.This solution, however, is costly and inflexible.
Link aggregation helps increase bandwidth by bundling a group of physical interfaces into a
single logical interface, without having to upgrade hardware. In addition, link aggregation
provides link backup mechanisms, greatly improving link reliability.
Link aggregation has the following advantages:
l
Increased bandwidth
The bandwidth of the link aggregation interface is the sum of bandwidth of member
interfaces.
l
Higher reliability
When an active link fails, traffic on this active link is switched to another active link,
improving reliability of the link aggregation interface.
l
Load balancing
In a link aggregation group (LAG), traffic is load balanced among active links of member
interfaces.
2.2 Principles
This section describes principles of link aggregation.
2.2.1 Concepts
, DeviceA and DeviceB are connected through three Ethernet physical
links. These three Ethernet physical links are bundled into an Eth-Trunk link. The bandwidth of
the Eth-Trunk link is the sum of bandwidth of the three Ethernet physical links, increasing the
bandwidth. The three Ethernet physical links back up each other, which improves reliability.
NOTE
Both devices of the Eth-Trunk must use the same number of physical interfaces, interface rate, duplex
mode, jumbo, and flow control mode.
Huawei AR530&AR550 Series Industrial Switch Routers
Configuration Guide - Ethernet Switching
2 Link Aggregation Configuration
Issue 01 (2014-11-30)
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