Interface Specification document for USSD Application Developer communicate with Mobicents USSD Gateway

[sokha]

Hello everyone,

Is there any interface protocol document (SIP/HTTP) for USSD
Application Developer?
I have been testing and playing around with Mobicents USSD Gateway
however i still does not understand on meaning of field used in xml
exchange between ussd application and ussd gateway.

ex:
// USSD gateway --> Application
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<request xmlns="http://mobicents.org/ussd">
<invokeId>1</invokeId>
<dialogId>2</dialogId>
<msisdn>31628838002</msisdn>
<ussdString>*123#</ussdString>
<ussdCoding>15</ussdCoding>
<result>false</result>
<lastResult>false</lastResult>
</request>
// USSD gateway <-- Application
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<request xmlns="http://mobicents.org/ussd">
<invokeId>2</invokeId>
<dialogId>2</dialogId>
<ussdString>Welcome to train station scheduler service. Press
following digits for 1) Train schedule. 2) Station location. 3)
Discount rates. 4) Promo</ussdString>
<ussdCoding>15</ussdCoding>
<result>false</result>
<lastResult>false</lastResult>
</request>
//USSD gateway -->Application
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<request xmlns="http://mobicents.org/ussd">
<invokeId>1</invokeId>
<dialogId>0</dialogId>
<ussdString>4</ussdString>
<ussdCoding>15</ussdCoding>
<result>false</result>
<lastResult>false</lastResult>
</request>
//USSD gateway <-- Application
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<response xmlns="http://mobicents.org/ussd">
<invokeId>1</invokeId>
<dialogId>0</dialogId>
<ussdString>There are no DISCOUNT! Pay the price!</ussdString>
<ussdCoding>15</ussdCoding>
</response>

// from this log, we can assume that there are two primary xml
structure , request and response and here is my questions:

1- InvokeId: what is the purpose of this field? how it is generated?
2-dialogId: what is the purpose of this field? how it is generated?
3-ussdstring : how many characters does the gateway support?
4-ussdCoding: 15 for 7bit coding scheme? how about 8bit? 16bit
5-result: what is the purpose of this field?
6-lastResult:what is the purpose of this field?


Regards,
sokha

[Bartosz Baranowski]

Bartosz Baranowski
JBoss R & D
==================================
Word of criticism meant to improve is always step forward.

Its a bit tricky.

GW                                                    APP

           ------ USSD REQ( InvokeId1)  ------>

           <------ USSD REQ( InvokeId2)  ------

           ------ USSD REQ( InvokeId3)  ------>

           <------ USSD ANS( InvokeId1)  ------

 Yes - its confusing, had hard time to grasp this myself. Now wrt to questions:

1- InvokeId: what is the purpose of this field? how it is generated?

This comes from TCAP, its  counter field which is kind of round robin byte for TCAP/MAP Dialog

2-dialogId: what is the purpose of this field? how it is generated?

This comes from MAPDialog. Its ID of .... :) 

3-ussdstring : how many characters does the gateway support?

ATM - depends on transport, if its M3UA, there is only limitation there.

We did not implement fragmentation and reasemble at SCCP iirc. 

4-ussdCoding: 15 for 7bit coding scheme? how about 8bit? 16bit

protected int ussdCoding; ?? This field is simple copy of one carried by MAP USSD Service messages. 

5-result: what is the purpose of this field?
6-lastResult:what is the purpose of this field?

Used to indicate if USSD Req carries result/lastResult for particular invoke ID - ie. If user Sends USSD Req with InvokeID =2, and response is for instance 500 bytes, application can fragment answer. This is exists to allow data fragmentation without support for it at SCCP. 

Regards,
sokha