Special VCX route is needed when dialing the restricted conference via the conference attendant

Special VCX route is needed when dialing the restricted conference via the conference attendant

1.                   Scenario：

There is no special requirement on the scenario，here are a VCX server and an IP Conferencing server.

2.                   Problem Description：

This problem is found during test in Lab， the symptom is as follows：

1）Can NOT dial in the restricted conference via the conference attendant;

2）Can enter this restricted conference directly, not via the conference attendant;

3）Can get in the same conference via the conference attendance if only change the conference type from restricted to public.

3.                   Analysis：

3.1 Introduction to background knowledge：

Participants access the conference attendant, input the conference name and passcode (Only for the restricted) using DTMF tones compatible to RFC 2833 (obsoleted by RFC 4733).

The conference attendant then uses SIP Refer method to do an unattended or blind transfer to the conference server via VCX, where SIP Refer-To header carries the conference name.

For the public conference, the conference attendant uses Refer-To header to carry the original conference name.                           

But for the restricted conference, the conference attendant will generate a 5-digit random number when the first participant accesses this restricted conference, and translate the conference name to another number comprising the conference name minimum numeric value appended by this 5-digit random number, save this translation into the Database, then send the translated number in the Refer-to header to VCX.          

If VCX has a route for this translated number to the conference server, the transfer will be successful, the conference server then look up the Database and get the original conference name back.  

If not, VCX will hang the transferred call until timeout.

Below is an example:

The conference name is 6600, and the conference name minimum numeric value is 6000.

When the conference type is public, the conference attendant will send 6600 in the Refer-To header to VCX; 

But if the conference type is restricted, the conference attendant will generate a 5-digit random number, taking 25308 for a example. and translate the conference name like this: 6600--->600025308, which is saved to the DB, then send 600025308 in the Refer-To header to VCX.               

When the transferred call arrives at the conference server, it will get the original conference name 6600 back after looking up the DB.

3.2 Troubleshooting：

The route plans are checked out on the VCX in this case as below：

Pattern 7000 is routed to the conference attendant with port 5092；

Pattern 66* is routed to the conference server with port 5060。

Therefore, when VCX receives the Refer message, the number in the Refer-to header is 600025308, which couldn’t be matched against any route plan, then VCX will hang the transferred call until timeout.

4.                   Solution：

There are two fixes here：

One: add a route plan whose pattern can match any translated number from the restricted conference name, such as 6000*，its route is the conference server;

Two: modify the existing route pattern 66* to 6*，so that this can match the original conference names, but also the translated number for the restricted conferences.