Equal Cost Multiple Path (ECMP) processing is a networking feature
that enables the firewall to use up to four equal-cost routes to the
same destination. Without this feature, if there are multiple equal-cost
routes to the same destination, the virtual router chooses one of
those routes from the routing table and adds it to its forwarding
table; it will not use any of the other routes unless there is an
outage in the chosen route. Enabling ECMP functionality on a virtual
router allows the firewall have up to four equal-cost paths to a
destination in its forwarding table, allowing the firewall to:
ECMP load balancing is done at the session level, not at the
packet level. This means the firewall chooses an equal-cost path
at the start of a new session, not each time the firewall receives
a packet.
