SIP User's Manual  354  Document #: LTRT-83310 
  Mediant 600 & Mediant 1000 
5.  Next, the par called A2 needs to be evaluated: 
•  The method type is ‘REGISTER’. 
•  Using SIP protocol ‘sip’. 
•  Proxy IP from ini file is ‘10.2.2.222’. 
•  The equation to be evaluated is ‘REGISTER:sip:10.2.2.222’. 
•  The MD5 algorithm is run on this equation and stored for future usage. 
•  The result is ’a9a031cfddcb10d91c8e7b4926086f7e’. 
6.  Final stage: 
•  The A1 result: The nonce from the proxy response is 
‘11432d6bce58ddf02e3b5e1c77c010d2’. 
•  The A2 result: The equation to be evaluated is 
‘A1:11432d6bce58ddf02e3b5e1c77c010d2:A2’. 
•  The MD5 algorithm is run on this equation. The outcome of the calculation is the 
response needed by the device to register with the Proxy. 
•  The response is ‘b9c45d0234a5abf5ddf5c704029b38cf’. 
At this time, a new REGISTER request is issued with the following response: 
 
REGISTER sip:10.2.2.222 SIP/2.0 
Via: SIP/2.0/UDP 10.1.1.200 
From: <sip: 122@10.1.1.200>;tag=1c23940 
To: <sip: 122@10.1.1.200> 
Call-ID: 654982194@10.1.1.200 
Server: Audiocodes-Sip-Gateway/Mediant 1000/v.6.40.010.006 
CSeq: 1 REGISTER 
Contact: sip:122@10.1.1.200: 
Expires:3600 
Authorization: Digest, username: 122, 
realm="audiocodes.com”, 
nonce="11432d6bce58ddf02e3b5e1c77c010d2", 
uri=”10.2.2.222”, 
response=“b9c45d0234a5abf5ddf5c704029b38cf” 
 
7.  Upon receiving this request and if accepted by the Proxy, the proxy returns a 200 OK 
response closing the REGISTER transaction: 
 
SIP/2.0 200 OK 
Via: SIP/2.0/UDP 10.1.1.200 
From: <sip: 122@10.1.1.200>;tag=1c23940 
To: <sip: 122@10.1.1.200> 
Call-ID: 654982194@10.1.1.200 
Cseq: 1 REGISTER 
Date: Thu, 26 Jul 2001 09:34:42 GMT 
Server: Columbia-SIP-Server/1.17 
Content-Length: 0 
Contact: <sip:122@10.1.1.200>; expires="Thu, 26 Jul 2001 10:34:42 
GMT"; action=proxy; q=1.00 
Contact: <122@10.1.1.200:>; expires="Tue, 19 Jan 2038 03:14:07 
GMT"; action=proxy; q=0.00 
Expires: Thu, 26 Jul 2001 10:34:42 GMT