Unified Communications Technology

Unified Communications brings a diverse array of collaboration tools to one central platform. Teams deploying a unified communications system are able to integrate phone systems, messaging apps, voicemail systems, and video conferencing services with real-time interoperability. In a Unified Communications suite, these tools are built on protocols that package, secure, and translate data to and from each connected device on a network. There are different models for delivery, but all unified communications technology is supported by four distinct protocol layers with which any device must interact.

Four Protocol Layers of Unified Communications Technology

Physical Layer

This layer, also knowns as the Network Interface layer, ensures connected devices on a unified communications platform are able to transmit information to the network. This starts with the ability to connect to the internet, but numerous permissions and precautions can be stipulated by a network. Each device is given a unique address on the network and their network interface capabilities are verified. Crucially, the network address is not a physical address. A voice call to a number normally associated with an office phone can be seamlessly re-routed to a cell phone at a different location.

Internet Layer

Sometimes referred to as the Network layer, the Internet layer sends and receives bundled packets of data from one device to another. Packet-switched technology is the bedrock for all Internet Protocol (IP) services and is the basis for the IP telephony systems that gave rise to voice over IP (VoIP), fax, and early video messaging services.

Transport Layer

Also knowns as the Host-to-Host layer, the Transport layer is responsible for end-to-end communication between IP devices on a network. The Transport layer is the primary security layer for all of the information travelling between communication devices. This layer streamlines data delivery, simplifying the structure of information accessed on the application layer. Hypertext Transfer Protocol Secure (HTTPS) and HTTP, which are used by the world wide web to shuttle communications between web browsers and servers, is one of the protocols of the transport layer.

Application Layer

Most end users only interact with the Application layer of a given program. All unified communications and collaboration tools - both software and apps - rely on this layer to translate and present the raw data sent and received on the underlying layers into identifiable sounds and images. The software or app involved with this later will run a series of protocol checks to ensure that any device interacting with the network meets the communication and security requirements of each preceding layer.

Session Initiation Protocol & Presence

The suite of tools included in a Unified Communications solution will vary, but all will be bundled in the application layer. Today, that application layer will interact with desktops, mobile devices, VoIP phones, and integrated programs using a protocol known as the Session Initiation Protocol, or SIP.

SIP is responsible for the initiation of every voice call, video conference, and app interaction on a Unified Communications platform. Likewise, the protocol has custody of all requests to expand, transfer, and terminate a communication.

A key component of Unified Communication is presence. Unified messaging, the confluence of instant messaging, text messaging, voicemail, chat, and web conferencing, relies on a SIP to verify the availability of a network user. However, not every available device on a communication system can receive all of the methods of communication that system distributes. A SIP identifies which media can be accessed by which device and routes communications accordingly.


Traditional telephone systems operate on a protocol similar to the operator/switchboard hand-off of generations past. Internal and external phone calls are routed to a central exchange, known as a private branch exchange or PBX. Traditional PBX identify the extension location of the desired party and connect the calls.

However, each call relies on a telephone line to carry the voice signal; more lines mean more wires hosted on-premise. This proliferation of hardware requires a system that “trunks,” i.e. ties, wires together into a sub-exchange that interacts directly with PBX. The wiring to and from the largest traditional PBX systems do indeed resemble trunks. Wires bound together reach several inches in diameter, branching off to the floors above and below, relaying voice call signals from one exchange to another.

For organizations with thousands of office lines or with serious growth ambitions, old school PBX presents significant cost, maintenance, and scaling considerations. More lines mean more hardware and more staff-hours dedicated to maintaining and servicing the system.

What SIP Trunking?

SIP trunking is the practice of dedicating a Session Initiation Protocol (SIP), or a portion thereof, to specific data relay functions. The SIP initiates, monitors, and terminates contact between connected parties. It also adds or removes conversation participants. Dedicating one SIP to one function of the unified messaging system (i.e. voice calls, document sharing, messaging, or video conferencing) allows organizations to scale the data flow of their business communications without scaling their attendant hardware and servicing costs.

SIP trunking enables an organization to handle all of their business communication needs with tethered SIPs communicating on the Application Layer, relaying data transmission responsibilities to the appropriate Transport Layer protocol without first contacting a central control program. Conceptually, this optimized data sharing system resembles the wire trunks of old PBX; in practice, it is a clean, efficient way to streamline data needs and keep communications flowing in real-time.

Enterprise Communications and Unified Communications Technology

The business applications of a Unified Communications system are as diverse as the ways a team chooses to collaborate. For this reason, service providers tend to tailor solutions to closely match a client’s business processes. Business communications can be optimized for customer support, user experience, or team meetings. Unlike old school chat programs or traditional phone systems, client needs determine which communications tools or products are prioritized and when they are available.

Learn more about the advantages of unified communications

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