What is BLOX?

Blox is a Session Border Controller(SBC) used to control VoIP signaling and media streams. SBC is responsible for setting up, conducting, and tearing down calls. SBC allows owners to control the types of call that can be placed through the networks and also overcome some of the problems caused by firewalls and NAT for VoIP calls. A common location for a stand-alone SBC is a connection point, called a border, between a private local area network (LAN) and the Internet. SBC polices real-time voice traffic between IP network borders ensuring your private network is robustly secure and fully manageable.


  • SBC is enabled with DPI Packet Inspection on VOIP traffic, supporting the Signatures for Key Malwares/Vulnerabilities observed in SIP Deployments like Extensions Enumeration DoS and Password Cracking. Supporting Open Source PBXs like Asterisk, FreeSwitch, TrixBox.
  • Handles the SIP-NAT issues observed in the common VOIP deployments.
  • Topology-hiding function is to prevent customers or other service providers from learning details about how the internal network is configured, or how calls being placed through the SBC are routed.

Advanced Features

  • Transcoding - SBCs can also allow VoIP calls to be set up between two phones by transcoding of the media stream, when different codecs are in use.
  • TLS/SRTP - support for signaling and media encryption.
  • Policy-based call routing, including crank back of call setup.

Basic Functions

  • Eliminates bad VoIP signaling and media protocol at the network boundary.
  • Built-in firewall which can controls IP Addresses/Port based Filtering, DOS/DDOS Attacks, IP Blacklist & NAT. It opens pinhole in the firewall to allow VoIP signaling and media to pass through.
  • Media bridging, which may include Voice over IP and Fax over IP.
  • Roaming Extension for Internal SIP PBX.
  • Support for SIP Outbound/Inbound Trunk and policies to route the calls.
  • DTMF Support for RFC2833/INBAND/SIP INFO