Enabling, disabling, or changing ECMP on an existing virtual router causes the system to restart the virtual router, which might cause existing sessions to be terminated.
Symmetric Returnto cause return packets to egress out the same interface on which the associated ingress packets arrived. That is, the firewall will use the ingress interface on which to send return packets, rather than use the ECMP interface, so the
Symmetric Returnsetting overrides load balancing. This behavior occurs only for traffic flows from the server to the client.
Select the maximum number of equal-cost paths: (2, 3, or 4) to a destination network that can be copied from the RIB to the FIB. Default is 2.
Choose one of the following ECMP load-balancing algorithms to use on the virtual router. ECMP load balancing is done at the session level, not at the packet level. This means that the firewall (ECMP) chooses an equal-cost path at the start of a new session, not each time a packet is received.