Physical architecture

This section describes OneContactPBX’s physical architecture from a network deployment perspective.


This solution includes network elements, OneContactPBX core component servers, database servers and client applications. The main components in this architecture are:

  • OneContactPBX servers: These servers host the OneContactPBX software.
  • OneContactPBX SIP server: Handles all call control operations. The SIP servers can be clustered.
  • OneContactPBX Web servers: Handles the OneContactPBX Web Portal and the OneContactPBX Web Services. This Web servers can be in a load balanced arquitecture.
  • OneContactPBX Presence server: Controls the extensions presence and BLF state.
  • Database servers: Microsoft SQL Server that manages OneContactPBX databases.
  • SIP Gateways: Network elements, present in an operator’s network, that perform the interconnection between between the PSTN network and the IP network.
  • Media Gateways/Media Gateway Controllers (MGC): Voice gateway for GSM, PSTN networks and video gateway for the UMTS network. The MGC should have SIP Trunking functionality and should be SIP compliant (SIP2.0 RFC3261, SDP RFC2327, RTP RFC3550).
  • Session Border Controller (SBC): Provides network border control functionalities, implements security, interoperability and reliability features. Collab’s OneSIPConnector is a limited alternative to a commercial SBC.
  • Storage: OneContactPBX servers need storage. As OneContactPBX components can be distributed and need to access the same storage, a shared storage is often used.

OneContactPBX’s servers are deployed in an x64 arquitecture running Windows Server 2012 R2 or later. All the hardware resources are scalable and can be deployed using multiple servers for high service availability.
OneContactPBX's servers and client applications communicate using several standard protocols:

  • SIP: Call setup and signaling.
  • SIPS: Secure call setup and signaling.
  • SDP: Session description, media formats negotiation.
  • RTP: Media (either audio or video) stream transport. The most common encodings are G.711 and G729, for audio; H.263 and H.264, for video.
  • SRTP: Secure media (either audio or video) stream transport.
  • Opus: Audio compression codec.
  • VP8: Video compression codec.
  • RTCP: RTP out-of-band control information.
  • HTTP/HTTPS: OneContactPBX web applications and web services.

If you want to know more about some of the concepts on this article, click here.