Adding Load Sharing to Routing Script

This article show you how to integrate a routing script filter that sorts matching routes by priority and weight (weight being used for load-sharing when multiple routes have the same priority).

Once ordered, the routes will be used one after the other until a route is working (according to Route Retry parameters).

NOTE: starting from version 3.0.80 this script is installed by default (only for new installations, or a fresh routing script)

Setting up Filter Scripts

To setup a Filter, the main script needs to be modified. The main script can be either simple_routing.rb, or any other script.

First, go to the routing script section of the Web portal

Gateway -> Routing scripts -> Example Scripts -> simple_routing.rb [Edit]

Three things need to be added. At the start of the script:

require 'priority_and_weight_load_balancer' unless defined?(PriorityAndWeightLoadBalancer)

In the main class:

include PriorityAndWeightLoadBalancer

  after_filter :method => :filter_by_priority_and_weight,
               :weight_by                 => :call_attempts,
               :default_load_share_mode   => :alternate_backup,
               :max_priority_delta        => -1

The final script will look like this (with possibly other filters also included):

require 'base_routing'
require 'priority_and_weight_load_balancer' unless defined?(PriorityAndWeightLoadBalancer)

class SimpleRouting < BaseRouting
  include PriorityAndWeightLoadBalancer
  
  route_match :call_field_name => :called
  route_match :call_field_name => :calling
  route_match :call_field_name => :nap
  route_match :method => :match_nap_availability
  route_remap :call_field_name => :called, :route_field_name => :remapped_called
  route_remap :call_field_name => :calling, :route_field_name => :remapped_calling
  route_remap :call_field_name => :nap, :route_field_name => :remapped_nap
  
  after_filter :method => :filter_by_priority_and_weight,
               :weight_by                 => :call_attempts,
               :default_load_share_mode   => :alternate_backup,
               :max_priority_delta        => -1
end

Adding New Custom Variables

You need to add two custom columns to use this script. There is a default value creates and it can be changed in each route afterwards.

Gateway -> Routes -> Create New Route Column

Name: priority
Type attributes: integer
Default: 10

Gateway -> Routes -> Create New Route Column

Name: weight
Type attributes: integer
Default: 100