• VoIP

    What is WebRTC

    At a high level, WebRTC is a way for browsers to have access to video, speakers and microphone directly without an intermediary like Java or Flash.  It’s most common use to-date has been for voice and video calling. WebRTC does NOT have a built-in protocol for call setup.  You can use an existing call setup protocol like SIP or make your own. OnSIP has open-sourced sip.js (https://sipjs.com/) as an OpenSource javascript library to add the SIP protocol to WebRTC. When using SIP as the call setup protocol for WebRTC, WebRTC is simply the conduit to the camera, speakers and microphone.  SIP does all the heavy lifting of notifying each end…

  • Technology,  VoIP

    MD5 Authentication – Working Example

    Ok – here is MD5 authentication: The PhD Course: SIP REGISTER is authenticated via MD5 authentication.  Everything you need to know is sent in the ‘Authorization’ line except the SIP Method which is at the top of the packet and in this case REGISTER – it could also be INVITE for example – and the user’s password.  That’s the key – that password. Here’s a sample REGISTER  Authorization string: Authorization: Digest username="agrabah_aladdin", realm="jnctn.net", nonce="5d02c49e00007aeb4d90b8fe974cf38a6d6a5b7515c24c19", uri="sip:agrabah.onsip.com", algorithm=MD5, qop=auth, cnonce="59f4a2601ec0874", nc=00000001, response="bb9ee2c392839058a01abcfa8192db47"   You create an A1 string for the user.  This string remains the same for the lifetime of the user’s password.  For this example we will assume Aladdin’s password is…

  • Technology,  VoIP

    Verizon Caught Blocking VoIP Traffic

    I was just on a phone call with a new customer who is setting up multiple retail locations.  The reason for the call was their backup network wasn’t working.  Whenever they tested the Verizon 4G LTE Wireless connected to Cradlepoint modem backup network, the phones would not be able to make or receive phone calls. Their IT staff was on the line and they were running Wireshark and grabbed a PCAP that seems to show that OnSIP at was responding to their request with a “500 Server Error”.   The actual text was: SIP/2.0 500 Server Internal Error Warning: 399 sipalg “Internal Error” Call-ID: b876f6fb4aad25a55546217e07dd4f82 CSeq: 47 REGISTER From:…