2 mins

Due to its increasing reliability and accessibility, in recent years, internet telephony technology has become a plausible choice for many businesses, allowing them to cut down on their communication costs whilst enjoying a rich communication experience.

SIP and VoIP provide the foundations for IP technology. Both technologies provide ample benefits and opportunities for the user to save money whilst increasing their productivity. Each protocol has pros and cons, and they are often used together.

What are SIP and VoIP?

Session Initiation Protocol, (SIP), is a powerful and efficient communications protocol which can be used to send multimedia messages to multiple parties - allowing people around the world to communicate over the internet using their computers and mobile devices.

Unlike similar services, such as PBX trunks, SIP trunks can carry all forms of media including voice, data, and video. As a result, SIP is usually preferred by companies with numerous branches or remote workers, whose employees depend heavily on multimedia communications.

Compared to VoIP and other similar systems, SIP systems can be more difficult to set up and manage, making them most suitable for companies with strong IT support.

Voice over Internet Protocol, (VoIP), is a communications protocol that is used to send voice messages over the internet. VoIP is a wide and rapidly expanding industry - popular apps and platforms such as Skype are increasingly using this technology. Particularly useful in small businesses with minimal locations, VoIP is a very common business protocol.

Unlike similar services, such as Time-Division Multiplexing (TDM) services, VoIP systems run via a data network as opposed to a circuit-switched network dedicated purely to telephony.

Key differences

In simple terms, VoIP means making or receiving phone calls over the internet or internal networks. SIP, on the other hand, is an application layer protocol that is used to establish, modify and terminate multimedia sessions such as VoIP calls.

A major difference between VoIP and SIP is their scope. VoIP is not a discrete technology in its own right. Rather, it is actually a family of technologies used within modern telecommunication networks, whereas SIP is a signalling protocol used within the VoIP umbrella.

A further difference is that, whilst VoIP sends only voice messages, SIP can carry all forms of media, not just voice messages. Transmitted via data networks, SIP trunks send packets, which may include voice, data, or video content. This means that SIP systems allow users to make voice and video calls online, often for free.

In terms of devices, VoIP handsets and SIP handsets also vary (although it should be noted that a SIP handset is also a VoIP handset). VoIP handsets, often referred to as VoIP phones, must be connected to a computer in order to make or receive calls. What's more, the computer must also be turned on. SIP phones, on the other hand, are able to perform without the need for a computer. They only require a modem to be able to work. In this sense, a SIP phone is more like a traditional phone as, unlike a VoIP device, it can function independently of a computer.

VoIP hosts handle traffic differently to SIP systems. SIP systems are processed by individual systems located on each user's system (these individual processing systems are known as 'user agents'). This peer-to-peer style system can handle large amounts of data and traffic as its users have access to much more bandwidth and resources. VoIP hosts, on the other hand, filter, organise, and direct traffic from one central network. When working on this type of system, large amounts of traffic can cause the system to become overloaded, impacting upon the overall performance. The single network system can also be beneficial, however, as the fewer points of communication lead to stronger security defences.

One of the main benefits of SIP over other VoIP protocols is that it has the ability to interact intelligently with other protocols. This means that it can adapt its signalling protocol to match that of the client system. In addition to this, it is fast, flexible and scalable to meet specific user needs.