Ozeki VOIP SIP SDK

Network entities | SIP

Protocols for VoIP connection

To be able to provide VoIP services several protocols need to be employed. On this page we focus on the four most common ones used to describe VoIP connections.

Protocol is a generic term, a standard that describes how the respective participants communicate with each other. For transmitting audio and video packets between communicating computers Real-Time Protocol (RTP) is used worldwide. But before audio or video media are transmitted between computers other protocols need to be used to find the remote device and to define the means by which media will be transmitted between the two devices. These are call-signaling protocols, such as Session Initiation Protocol (SIP).

VoIP connections are basically described with the following protocols:

1. SIP: Session Initialization Protocol

   This article is a brief introduction about the Session Initiation Protocol (SIP) that can be used to create, modify and terminate two-party or multiparty sessions over Internet Protocol.
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2. RFC: Request for Comments

   This page contains a comprehensive list of RFC documents that specifies all of the standard protocols that are required for establishing VoIP calls.
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3. UDP: User Datagram Protocol

   Find out more about the User Datagram Protocol (UDP) that is a part of the IP suite of protocols and it is used for data transferring in VoIP technology.
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4. SDP: Session Description Protocol

   This protocol conveys information on media streams in multimedia sessions. It describes media components and conciliates between participants (codecs and transfer protocols).
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5. RTP: Real-Time Transport Protocol

   It transmits audio and video packets between communicating computers over the network. To identify packages it uses time stamps and ordinal numbers.
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6. RTCP: Real-Time Control Protocol

   This article is a brief introduction about the Real-Time Transport Control Protocol that is a companion protocol of the RTP and it is used to send/receive most media over IP.
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7. H323 Protocol

   This page provides you the basic knowledge about H323 protocol that addresses call signaling/control, multimedia transport/control, and bandwidth control for conferences.
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More information

• Define voip
• Network entity
• Voip supported codec
• SMS vs VoIP messaging

Network entities | SIP