SIP http:/ 1 3 2 4 3 5 4 7 5 8 6 9 7 10 8 11 9 12 10 13 11 .14 12 15 1 A REGISTER (1) 401(2) REGISTER(3) 200 OK (4) 1 A REGISTER 2 / 401 Unauthorized 3 REGISTER 4 REGISTER / A 200 OK 2 3 4 5 6 7 8 9 10 11 12 /IT Vo I P NGN IMS FMC GSM CDMA 3G IPTV SP linux/unix voip NGN 3G http:/ http:/ =1&extra=page%3D1
