CEF Load Balancing Algorithm

  • By default, CEF uses per-destination load balancing
  • In the event of an existing parallel path, a hash algorithm is used to determine the path to be chosen for each destination
  • In cases when load sharing is done simultaneously on interfaces of different physical types, such as serial and tunnel, CEF takes the single path.
  • In order to utilize all the parallel paths in CEF and load balance the traffic, you must enable per-packet load balancing when you have different physical interfaces like serial and tunnel.
  • So, on the basis of the configuration and topology (serial or tunnel), load sharing can fail to work correctly with the default CEF load balancing mode.