How to configure BSNL SIP Trunk on Asterisk or Issabel
BSNL now provides SIP Trunk with DIDs in genreal they call it SIP PRI and asking you to buy channels as they were selling copper PRI links .Now they are providing same service with fiber optice cables on FTTH connections.
They are giving fiber link as same they are providing FTTH internet services with ONT and providing PRI service through SIP Protocal over the VPN using OPEN VPN or SoftEther .
Depend on your convinent they are asking which VPN service you will use . Here I am using OPENVPN. But before implementing SIP PRI from BSNL as I was thinking it can be use over OPENVPN from any internet network .
but they have played the game that there OPENVPN server can be accessed by only there network they have provided and sip server can be access only over VPN connection .I dont know why they have used OPENVPN if you are using IP based security and SIP authentication and SIP registration . they have just made it complicated if your Applicance does not support OPENVPN then you have to used additional device or router which support OPENVPN.then you can reach there SIP Proxy server.
Now below are the breif steps to configure BSNL SIP trunk

Step 1- Configure the OPENVPN Client to access there SIP server as OPENVPN configuration file they have provided as example cityname_phone_number.opvn file . Note .opvn is the extension of the file .
VPN Server Details VPN Server: OpenVPN VPN Server Primary IP: 117.19.21.93 VPN Server Secondary IP: 117.19.21.94 VPN Client Details Virtual Ethernet Port IP: 172.0.1.13 Mask: 255.255.224.0 Gateway: 172.0.1.1
Step 2- Configure the routing to access the BSNL SIP server ping and test if you are able to reach ther SIP proxy server. if you are able to reach then you go to next step.
Step -3 Configure SIP trunk and information provided by them .
For Example :-
SIP Account Details SIP Server Domain : upe.stbi.ims.bsnl.in Proxy IP: 10.19.15.1 User ID: +91522222222 Authentication ID: +91522222222 Password: bsnlipvpn@123 ==========================================================
disallow=all allow=ulaw&alaw type=friend dtmfmode=rfc2833 qualify=yes nat=force_rport,comedia insecure=invite,port host=10.19.15.1 username=+91522222222 secret=sipvpn@123 fromdomain=upe.stbi.ims.bsnl.in fromuser=+91522222222 defaultexpirey=120 canreinvite=no ;context=trunkinbound context=from-pstn maxexpiry=600 progressinband=yes
Register String : +91522222222:sipvpn@123@upe.stbi.ims.bsnl.in Note :- I have changes the IP addresses and authentication for security resion. For Support whatsApp +918318841546