Resilient LAG Hashing Configuration and Example

Configure the LAG hashing mode as advanced-resilient. By default, the hash-mapping field is disable false all.

Without resilient mode, each traffic flow (the flow definition depends on the hash-mapping configuration) is load balanced on one port of the LAG. This distribution is done via a hashing algorithm. If a port on this LAG is added or removed (link up/down), the hash will change all flows to be re-distributed on the remaining ports. It is typically not important if the device on the other side of the LAG is a router or a switch but could be important if the LAG is sending traffic to equipment (like a cluster of servers) that handles traffic differently on each port (for example, distributing http sessions on multiple servers).

In resilient mode, a removed link does not trigger the redistribution of traffic on the remaining ports. Only the traffic from the removed port will be distributed to the remaining ports. An added link does not trigger redistribution of traffic on the remaining ports. The added link will share the traffic on the remaining ports.

Currently, all the switch models, except Tomahawk based switches, support the resilient LAG hashing.

Configuration:

  set interface aggregate-ethernet ae10 hash-mapping mode advanced-resilient

Examples:

Configure one lag with three ports

   set interface gigabit-ethernet ge-1/1/1 ether-options 802.3ad ae10
   set interface gigabit-ethernet ge-1/1/2 ether-options 802.3ad ae10
   set interface gigabit-ethernet ge-1/1/3 ether-options 802.3ad ae10

Configure the lag hash mode advanced-resilient

   set interface aggregate-ethernet ae10 hash-mapping mode advanced-resilient

Configure the hash-mapping field 

  set interface aggregate-balancing hash-mapping field ip-destination disable false
  set interface aggregate-balancing hash-mapping field ip-source disable false

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