Ethernet Link Redundancy Overview

You can use 802.3ad Link Aggregation (LAG) to configure Ethernet link redundancy for Fast Ethernet and Gigabit Ethernet interfaces. Ethernet link redundancy enables you to protect against physical link failure and account for network topology changes that redirect network traffic to redundant ports.

The following configurations are available:

For information about the modules that support link aggregation, see ERX Module Guide, Appendix A, Module Protocol Support and E120 and E320 Module Guide, Appendix A, IOA Protocol Support.

Ethernet Link Redundancy Configuration Models

The link connections determine the configuration model for link redundancy. The following connection types are available:

The type of hardware used for connections further characterizes the single-homed and dual-homed configuration models. The following hardware types are available:

Figure 21 illustrates the configuration models for Ethernet link redundancy.

Figure 21: Ethernet Link Redundancy Configuration Models

Ethernet Link Redundancy Configuration
Models

Ethernet Link Redundancy Configuration Diagrams

The diagrams in this section illustrate examples of Ethernet link redundancy configurations. The diagrams display adjacent ports bundled in a LAG.

GE-2 Line Module Configurations

These diagrams compare physical port redundancy and link redundancy on a GE-2 line module.

Figure 22 displays a GE-2 line module with physical port redundancy on both ports.

Figure 22: GE-2 Line Module Using Physical Port Redundancy

GE-2 Line Module Using Physical Port
Redundancy

Figure 23 displays a single-homed configuration with port 0 backing up port 1 on a GE-2 line module.

Figure 23: Single-Homed GE-2 Line Module Configuration

Single-Homed GE-2 Line Module Configuration

FE-8 Line Module Configurations

Figure 24 displays an FE-8 line module with a link failure in a 1:N single-homed configuration.

Figure 24: Single-Homed FE-8 Line Module Configuration (1:N)

Single-Homed FE-8 Line Module Configuration
(1:N)

Figure 25 displays an FE-8 line module with four redundant Ethernet links in a 1:1 configuration.

Figure 25: FE-8 Line Module with 4 Redundant Ethernet Links (1:1)

FE-8 Line Module with 4 Redundant Ethernet
Links (1:1)

E120 and E320 Routers Configurations

Figure 26 and Figure 27 display link redundancy configurations on the E120 and E320 routers.

Figure 26 displays a single-homed 1:4 configuration on an E120 router.

Figure 26: Single-Homed GE-4 IOA Configuration (1:4)

Single-Homed GE-4 IOA Configuration (1:4)

Figure 27 displays an E320 router with 1:N configuration across IOAs.

Figure 27: GE-8 IOA Configuration Across IOAs (1:N)

GE-8 IOA Configuration Across IOAs (1:N)

Dual-Homed Configurations with LAG Disabled

Figure 28 displays how you can configure Ethernet link redundancy with LACP disabled locally using a dual-homed configuration. LACP is disabled because there is no LAG at the peer.

Figure 28: Dual-Homed Configuration (1:1)

Dual-Homed Configuration (1:1)

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