ENUM Query

Introduction

Starting with release 3.1, it is possible to issue ENUM Query requests to DNS servers from routing scripts. To do so, the params[:enum_query] object must be filled with the required ENUM Query attributes params[:enum_query][:fqdn] and an exception must be raised with reason :enum_query_required.

When ENUM Query completes, the routing script is called again with the result. The params[:enum_query] object will be filled with the ENUM Query attributes from the response. The params[:enum_query][:result] field will also contain a string indicating the result of the ENUM Query:

• ok: The ENUM Query was successful.

• timeout: The ENUM Query was not answered.

The params[:enum_query][:responses_list] field will contain a list of hash responses for each NAPTR records.

NAPTR records contain:

• :uri

• :order

• :preference

Example:

---

params[:enum_query][:responses_list] [{:order=>"200", :preference=>"10", :uri=>"!^03111.*$!sip:[e-mail]!"}, {:order=>"100", :preference=>"1", :uri=>"!^03222.*$!sip:[e-mail]!"}, {:order=>"200", :preference=>"1", :uri=>"!^03111.*$!sip:[e-mail]!"}]

---

Using enum_called_remap.rb before filter script allows handling of ENUM query requests/responses. The match and replace regular expression from ENUM query responses are applied to params[:call][:called] to get "new called". This script allows update of the call parameters according to "new called" value. Refer to enum_called_remap.rb before filter script to get instructions on how to integrate this script into the main routing script (i.e. simple_routing_sbc.rb):

---

... require 'enum_called_remap' unless defined?(EnumCalledRemap) ... include EnumCalledRemap ... before_filter :method => :enum_called_remap ...

---

Resolve ENUM Query down to type A records

The ENUM query could also resolve uri from responses and get matching outgoing NAP, NAP proxy IP and port through a sequence of DNS queries (i.e. NAPTR, SRV down to type A records). This behavior could be requested using "dns_query" parameter:

---

params[:enum_query][:dns_query] = true

---

When ENUM and DNS Queries complete, the routing script is called again with the results. The params[:enum_query] and params[:dns_query] objects will be filled with the ENUM Query and the DNS Query attributes from the responses. The DNS query responses are available through params[:dns_query][:responses_list] call parameters:

---

params[:dns_query][:responses_list] [{:nap=>"NAP_UDP", :nap_proxy_ip=>"10.3.14.191", :nap_proxy_port=>"8080", :transport=>"UDP", :order=>"100", :preference=>"1", :priority=>"0", :weight=>"5"}, {:nap=>"NAP_TCP", :nap_proxy_ip=>"10.3.14.192", :nap_proxy_port=>"8081", :transport=>"TCP", :order=>"100", :preference=>"2", :priority=>"1", :weight=>"10"}]

---

Add dynamic routes

The ENUM query could also add dynamic routes base on DNS query responses. This could be requested using the "add_dynamic_routes" call parameter:

---

params[:enum_query][:dns_query] = true params[:enum_query][:add_dynamic_routes] = true

---

Note that it is mandatary to send DNS query to add dynamic routes.

The "base_routing.rb" script version should be greater then 1.37 in order to allow dynamic routes creation base on DNS query responses.

When requesting to add_dynamic_routes, the dns_query responses are used to create routes. Make sure that your configuration includes a route with remapped_nap = "Registered or DNS users". A route will be created for each DNS query responses. The routes "remapped_nap" takes NAP value from DNS query responses.

It is required to modify main routing script (i.e. simple_routing_sbc.rb) to forward IP/port values from params[:routes] to params[:call] like we are doing for NAP. See following example:

---

...

# This will select the outgoing NAP for this call according to the "remapped_nap" route parameter route_remap :call_field_name => :nap, :route_field_name => :remapped_nap

# This will select the outgoing NAP proxy ip address for this call according to the "remapped_nap_proxy_ip" route parameter route_remap :call_field_name => :nap_proxy_ip, :route_field_name => :remapped_nap_proxy_ip

# This will select the outgoing NAP proxy port for this call according to the "remapped_nap_proxy_port" route parameter route_remap :call_field_name => :nap_proxy_port, :route_field_name => :remapped_nap_proxy_port ...