Contents

1Introduction 2CommuniGate Configuration 2.1Generating the Router Rules 2.2External Helper with DNS lookup 3Conclusion

[top]Introduction

ISN provides an easy way for campuses, enterprises, and service providers to acquire globally-unique and globally-routable subscriber numbers to support new communications services.

[top]CommuniGate Configuration

By adding router rules and an optional helper application, CommuniGate Pro can be configured to support ISN dialing without the need for a special dialing prefix (012, for example). Users can simply dial 1234*123.

[top]Generating the Router Rules

In order to route ISN numbers, we must create router rules.

To route ISN numbers, two wildcards are needed, one for the subscriber number (the number before the asterisk) and one for the ITAD (the number after the asterisk).

The CommuniGate Pro router rules are limited to one wildcard per rule. The easiest way to get around this limitation is to generate a router rule for each ITAD. CommuniGate has been tested with over 10,000 router rules without any impact on performance, so adding a few thousand for ISN routing shouldn't cause any problems[1].

Below is a perl script that will generate ISN rules for the TRIP ITAD Numbers 256 - 2000. Only ITADs up to 730 have been issued as of this writing.

The ISN.pl script:
Create an ISN.pl file on your system and run
or use the attached ISN.txt file.

The rules look like:

• Copy the text from ISN.txt and paste them into the CommuniGate Pro Web Admin Interface in the Settings->Router tab.
• Click the Update button to save your work.
• You're done with basic configuration.
• Test your work by entering 613*262 into the Test Address box, change the drop-down box to Signal, and Click the Test button.
• If your get:
  Routed to SIP host fwd.pulver.com(613@fwd.pulver.com) (can relay)
  your configuration is working properly.

This configuration works by sending an ISN-style SIP INVITE to the freenum.org SIP proxy. The SIP proxy then returns a 302 Moved Temporarily style reply. As an example: 613*262 is an ISN for extension 613 on ITAD 262 (Free World Dialup.) When a user dials 613*262, CommuniGate Pro will try to reach 613*262@freenum.org, that INVITE will be re-written by the Freenum redirector to be 613@fwd.pulver.com which in turn will lead to an echo test on the Free World Dialup system.

[top]External Helper with DNS lookup

Instead of sending a SIP INVITE to the freenum.org SIP proxy, the preferred configuration below explains how to configure CommuniGate Pro to use an external helper application to perform an ENUM style DNS lookup to return the destination SIP URI.

• Copy the attached cgp-ISN-resolver.pl perl script into the /var/CommuniGate directory on your CommuniGate Pro server.
• Make sure that the user that owns the CommuniGate files also owns the cgp-ISN-resolver.pl file.
• Make sure that the owner can execute the cgp-ISN-resolver.pl file.
• Go to the CommuniGate Pro Web Admin Interface.
• Navigate to the Settings->General->Helpers tab.
• Check External Authentication.
• Set Time-out to 5 sec.
• Set Program Path to /var/CommuniGate/cgp-ISN-resolver.pl
• Set Auto-Restart to 5 min.
• Click the Update button.
• If you didn't receive any red error messages, the helper application is running.
• Go to the CommuniGate Pro Web Admin Interface Settings->Router tab.
• Find the following line in the router settings:
  
  Code:

  S:isn = freenum.org

• Change the line to:
  
  Code:

  S:isn = external

• Click the Update button to save your work.
• Test your work by entering 613*262 into the Test Address box, change the drop-down box to Signal, and Click the Test button.
• If your get:
  Routed to SIP host fwd.pulver.com(613@fwd.pulver.com) (can relay)
  your configuration is working properly.

[top]Conclusion

Test your settings by dialing an ISN number from an IP phone[2] registered with your CommuniGate Pro server.