ECMP is supported on all Palo Alto Networks firewall platforms, with hardware forwarding support on the PA-7000 Series, PA-5000 Series, PA-3060 firewalls, and PA-3050 firewalls. PA-3020 firewalls, PA-500 firewalls, PA-200 firewalls, and VM-Series firewalls support ECMP through software only. Performance is affected for sessions that cannot be hardware offloaded.
ECMP affects the route table capacity because the capacity is based on the number of paths, so an ECMP route with four paths will consume four entries of route table capacity. ECMP implementation might slightly decrease the route table capacity because more memory is being used by session-based tags to map traffic flows to particular interfaces.