Technical protocols in VoIP communication

VoIP has been the talk of the town for the past few years. Everything is good for those who know about this technology. Yet, there is still a large audience that needs to be well aware of it. Our VoIP protocol technical overview is intended to provide vital information to users who wish to use this communication method. We are going to discuss the basic information and then jump to our actual topic, which is VoIP protocols and their functionality. Let’s get started now.

What is VoIP, or Voice over Internet Protocol?

VoIP is a tool that helps transmit voice over the internet. There is also a facility for the transmission of video content. Yet, that varies from service to service. For instance, Contactivity is currently dealing with voice content transmission. The best thing about the latest communication standard is that it allows users to make and receive calls from anywhere in the world. Most importantly, they do not have to stick to their offices or use some special phone. Users can make and receive calls using laptops, smartphones, and other compatible smart devices. Communication using VoIP tends to be more secure and safe than traditional telephone lines. This is because the technology uses the internet to send and receive data packets. Most service providers, like Contacitivty, use cloud technology for better results and quality.

Understanding VoIP Protocols: A Technical Overview

Voice-over-IP makes communication better and easier. It is reliable, durable, and even scalable. VoIP cloud telephony uses the internet to offer these benefits as compared to traditional landline phones. Thus, it is a good option for businesses that provide customer support services. Before wasting further time, let us get started with the technical protocols for VoIP communication:

Session Initiation Protocol, or SIP:

SIP, or Session Initiation Protocol, is one of the most common protocols used in VoIP telephony. For understanding VoIP signaling protocols, you need to have a basic knowledge of every protocol. Considering this, the SIP establishes, maintains, and terminates connections between all parties. It is one of the basic protocols that has special operations to perform. Likewise, it identifies call participants and then defines the order and format of messages. There is a sequence of protocols that play their role. For instance, when a connection is established by SIP, RTP takes control of the communication. SIP operates at the application layer of the OSI model.

Real-Time Transport Protocol (RTP):

The Real-Time Transport Protocol handles the real-time transmission of audio and video content.  Everything happens in real time between endpoints during a VoIP call. This protocol is activated when SIP establishes communication between endpoints. This protocol takes over audio and video conferencing. This protocol works with the RTP Control Protocol (RTCP). The RTCP provides feedback on the quality of communication. Considering the technical aspects of VoIP transmission, RTP handles the transmission of voice packets, the handling of packet loss and jitter, and managing synchronization between the sender and receiver.

RTP Control Protocol (RTCP):

As mentioned above, the RTP control protocol works with RTP. It ensures the quality of service and provides statistics about packet delivery. It handles tracking call termination. After tracking calls, it provides information about packet loss, packet counts, and round-trip delay time to the calling parties. Thus giving valuable insights to recipients about the call quality and troubleshooting issues, if any. In simple words, it provides VoIP packetization and transmission details to improve service quality.

Secure Realtime Transport Protocol (SRTP):

It is a security protocol that works with RTP. It ensures the security of data packets that are delivered live. This protocol encrypts data and authenticates messages and their integrity. Moreover, it ensures replay attack protection to deal with all possible threats. As this protocol works with RTP, it is an option to have SRTP. However, it is pertinent to mention that it is one of the common protocols that VoIP service providers like Contactivity consider useful.

Session Description Protocol (SDP):

SDP works alongside SIP. It is a signaling protocol that shares basic information between call recipients. It handles providing information about ongoing sessions. For instance, it shares session name, purposes, start time, end time, session invitation, and session announcements. It also gives information about endpoint port numbers, codecs, and the type of media in sessions.

MGCP, or Media Gateway Control Protocol:

MGCP is a transport protocol that has the responsibility of controlling voice gateways between PSTN and the Internet. Not to mention, PSTN is the abbreviation for public switch telephone networks. This protocol is necessary for VoIP calls using both the Internet and the PSTN. Thus providing the gateway to control the packet transmission between call recipients. This protocol is used with SIP to control and manage VoIP calls.


H.323 is considered the precursor of SIP. It is a system specification that has many protocols. All these protocols help in establishing the session to send data packets over the IP network. The VoIP protocol technical overview cannot be completed if we miss this protocol. The reason is that this protocol is responsible for call signaling, handling registration, and opening channels for a VoIP call. As discussed, it has several protocols; therefore, it has a large scope. It can be used for audio, video, and data communication. For instance, H.225 is for signaling, H.245 is for control signaling, and H239 is for data sharing.


The overview of VoIP communication standards cannot be completed if we don’t take note of Jingle. Although it is less popular, it is perfect for businesses that offer message transmission. It is designed to support instant messaging services. This protocol is responsible for peer-to-peer (P2P) transmission. Jingle is a VMPP extension and signaling protocol. It is perfect for file sharing, structured data transmission, and instant messaging.

What is Contacitivity’s take on the VoIP protocol?

A technical overview of VoIP protocols from Contactivity is an effort to make sure all our interested users have the basics. Experts at Contactivity believe that protocols play an important role in voice and video transmission over the Internet. All protocols, as mentioned earlier, bundle up to provide services that are beyond questionable limits. The fairness of these protocols depicts the service quality. Contactivity has always prioritized the comfort of its clients. Thus, it has always strived to ensure the technical superiority of its services. This helps in rendering services of the highest quality.


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