where i can get the architecture document of JAIN SIP Stack

Parasuraman Kumarasami <[email protected]> Wed, 10 Dec 2008 12:27:07 +0530

Newsgroups	gmane.comp.voip.nist-sip,gmane.comp.java.springframework.modules.devel
Message-ID	<[email protected]>

Hi All,

I would like to know where the jain sip stack architecture or design 
document? or is there any specification for the request and response 
constructed by the jain sip stack must have only one From header or To 
Header (Those headers are not implemented has a list)?

example of sip message as follows

1).SIP/2.0 401 Unauthorized
Call-ID: [email protected]
CSeq: 19 REGISTER
From: <sip:[email protected]>;tag=1b3545a5
From: <sip:[email protected]>;tag=1b3545a5
From: <sip:[email protected]>;tag=1b3545a5
To: <sip:[email protected]>;tag=70f19ee0
Via: SIP/2.0/UDP 
127.0.0.1:5060;branch=z9hG4bK412bb3d200eb1cf8977af4ae4f7844c0
Contact: "UserA" <sip:[email protected]:5070;transport=udp>
Content-Length: 0

2).SIP/2.0 401 Unauthorized
Call-ID: [email protected]
CSeq: 19 REGISTER
From: <sip:[email protected]>;tag=1b3545a5
To: <sip:[email protected]>;tag=70f19ee0
To: <sip:[email protected]>;tag=70f19ee0
To: <sip:[email protected]>;tag=70f19ee0
Via: SIP/2.0/UDP 
127.0.0.1:5060;branch=z9hG4bK412bb3d200eb1cf8977af4ae4f7844c0
Contact: "UserA" <sip:[email protected]:5070;transport=udp>
Content-Length: 0

is it possible to do so?
if so how do i?

Regards
Parasuraman