Forigate routing

ECMP

Equal cost multi-path (ECMP) is a mechanism that allows a FortiGate to load-balance routed traffic over multiple gateways. 

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

Configure ECMP Load Balancing method

Fortigate-Local (settings) # set v4-ecmp-mode 
source-ip-based         Select next hop based on source IP.
weight-based            Select next hop based on weight.
usage-based             Select next hop based on usage.
source-dest-ip-based    Select next hop based on both source and destination IPs.
 

Verify from CLI

Fortigate-Local # get router info routing-table database 

Codes: ....

Routing table for VRF=0

S    *> 0.0.0.0/0 [10/0] via 10.200.1.254, port1, [1/0]

     *>           [10/0] via 10.200.2.254, port2, [1/0]

C    *> 10.0.1.0/24 is directly connected, port3

C    *> 10.200.1.0/24 is directly connected, port1

C    *> 10.200.2.0/24 is directly connected, port2