Introduction

One of the biggest benefits of EVPN is its capability to load balance. This document will go over the various load balancing methods.

Overview

• There are four main topologies that can be used with EVPN and two of them include load balancing:

• Single-Homed Device (SHD)
  • CE connected to only one PE.
• Single-Homed Network (SHN)
  • CE connected to a single Network.
• Multi-Homed Device (MHD)
  • CE connected to multiple PEs.
• Multi-Homed Network (MHN)
  • Same network connected to multiple PEs.

• MHD and MHN support load balancing.
• There are two method for load balancing:
  • Single Active Redundancy Mode - one PE acts as the primary while the other as the backup.
  • All-Active Redundancy Mode - both PE are used for load balancing.

source: cisco.com

Single Active

• One PE acts as the primary PE for forwarding frames. The other PE acts as a standby backup.
• The active PE is also the Designated Forwarder (DF).
• Using the MHD topology, CE connects to two PEs via two separate Ethernet bundles. Load balancing is performed per-vlan

All Active

• Using the MHD topology, CE connect to two PEs via a single Ethernet bundle. Both PE forward traffic within the same VLAN.

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