Equal cost multi-path

Equal cost multi-path (ECMP) is a mechanism that allows a FortiGate to load-balance routed traffic over multiple gateways. Just like routes in a routing table, ECMP is considered after policy routing, so any matching policy routes will take precedence over ECMP.

ECMP pre-requisites are as follows:

  • Routes must have the same destination and costs. In the case of static routes, costs include distance and priority
  • Routes are sourced from the same routing protocol. Supported protocols include static routing, OSPF, and BGP

ECMP and SD-WAN implicit rule

ECMP and SD-WAN implicit rule are essentially similar in the sense that an SD-WAN implicit rule is processed after SD-WAN service rules are processed. See Implicit rule to learn more.

The following table summarizes the different load-balancing algorithms supported by each:

ECMP

SD-WAN

Description

GUI

CLI

source-ip-based

Source IP

source-ip-based