1 ethernet link aggregation configuration, Overview, Basic concepts – H3C Technologies H3C S5120 Series Switches User Manual

Page 99: Ethernet link aggregation configuration

1-1

Ethernet Link Aggregation Configuration

This chapter includes these sections:

Overview

Ethernet link aggregation, most often simply called link aggregation, aggregates multiple physical

Ethernet links into one logical link to increase link bandwidth beyond the limits of any one single link.

This logical link is called an aggregate link. It allows for link redundancy because the member physical

links dynamically back up one another.

As shown in

, Device A and Device B are connected with three physical Ethernet links. These

physical Ethernet links are aggregated into an aggregate link, Link aggregation 1. The bandwidth of this

aggregate link can be as high as the total bandwidth of these three physical Ethernet links.

Figure 1-1 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. 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.

There are two types of aggregate interfaces: bridge-aggregation (BAGG) interfaces, which are Layer 2

aggregate interfaces, and route-aggregation (RAGG) interfaces, which are Layer 3 aggregate

interfaces. When an aggregate interface is created, an aggregation group of the same type and

numbered the same is created automatically. For example, when you create interface

Bridge-aggregation 1, Layer 2 aggregation group 1 is created.

To a Layer 2 aggregation group, you can assign only Layer 2 Ethernet interfaces.