SIP Calling: Definition, Uses & Benefits

SIP Calling Article Summary

1. SIP calling uses the Session Initiation Protocol to support voice, video, and other multimedia communications over an Internet connection.
2. Businesses can use SIP to reduce communication costs, improve scalability, support remote work, and centralize communications across devices and platforms.
3. Getting started with SIP typically requires a SIP account, a compatible client, a reliable Internet connection, and suitable communication equipment.

SIP solutions are now a major consideration for companies looking to improve the way they communicate and collaborate. But why is SIP calling so important today? In many cases, it comes down to the availability and quality it provides.

Real-time communication services can achieve availability of more than 99.9% [1], which helps explain why businesses are moving from traditional landline telephony to digital solutions. You can use SIP through VoIP technology or other data communication providers and integrate it with other telecommunications platforms and tools.

This article explains everything you need to become familiar with SIP, whatever configuration or provider you choose to use. Let’s get started!

What Is SIP?

SIP stands for Session Initiation Protocol, a protocol used to establish, modify, and terminate communication sessions over VoIP and other Internet- and cloud-based communication platforms [2]. You can use SIP calling through an application for different types of online communication, including voice and video chat, virtual and augmented reality, and even gaming.

SIP is an application-layer signaling protocol rather than a media transport protocol in itself. It can establish and manage multimedia sessions while working alongside other protocols that describe or carry the media involved [2] [3].

What Is a SIP Call?

In practical terms, a SIP call is a communication carried over an Internet connection—Wi-Fi, Ethernet, or cellular data—using the SIP protocol described above. These calls do not travel through traditional telephone lines and can therefore support a wider range of content.

In addition to voice communications, you can hold video conferences and go even further, since SIP calling also opens up possibilities for gaming, augmented reality, and virtual reality. SIP was designed to establish, modify, and terminate sessions that can include Internet telephone calls, multimedia conferences, and other forms of multimedia communication [2].

What Is the Difference Between a SIP Phone and an IP Phone?

SIP and VoIP are often grouped under the same umbrella, particularly when discussing the equipment used to support these protocols. However, there are some important differences.

VoIP phones include the following solutions:

• Hardware solutions, such as physical desk phones that look like traditional phones but connect to an IP network
• Software solutions, such as softphones that allow users to make IP calls in the cloud without a physical telephone

Here are the differences between SIP and VoIP:

• SIP manages communications through multimedia sessions. VoIP only supports voice calls. As a result, SIP can handle multiple forms of media, while VoIP is limited to sending and receiving calls and voice messages.
• There are also differences in terms of hardware. SIP devices are independent and only require a modem. VoIP devices, meanwhile, require a computer connected to a modem to make and receive calls.
• Finally, a SIP exchange uses several modules to manage different functions. SIP can therefore handle large volumes of both data and traffic. In contrast, a VoIP session uses a single module to manage all functions.

At protocol level, SIP provides signaling and session-management functions and can work alongside other Internet protocols to create a broader multimedia communications architecture [2].

The Difference Between SIP and Landlines

Landlines have existed since the early days of telecommunications. However, tried-and-tested technology is not always the best fit for your business. Modern telephony solutions are often necessary to meet the requirements of companies looking to grow.

Using the SIP protocol is simpler than using conventional telephone lines. You simply need an agreement with a telecommunications company that has traditional telephone lines and can transfer your calls to the public switched telephone network, or PSTN.

SIP systems can interoperate with the PSTN through gateways, allowing SIP-based endpoints and traditional telephone networks to participate in the same call flow 44.

PSTNs use various technologies to route calls to their intended recipients. You do not need to install any particular type of computer hardware. SIP can be an entirely software-based solution.

With SIP, a “trunk”—a communication link that carries signals between two points on a network—on your smartphone allows you to use the Internet to connect to your telephone network. SIP networking can be as simple as making a call. Let’s take a closer look at how it works.

How Do You Make a SIP Call?

The simplest way to make a SIP call is by using your smartphone. If your smartphone settings do not support SIP calling, you can download a SIP application for your computer or smartphone.

Older smartphones may not support SIP calling, while newer models generally do.

If your employees use their own smartphones for work, consider providing them with your SIP provider’s installation and troubleshooting instructions. SIP calling applications extend your phone’s VoIP capabilities, allowing employees to use smartphones as business tools wherever they are in the world.

Personally owned mobile devices can provide employees with flexible access to workplace resources, although businesses also need to address the specific security and privacy considerations associated with BYOD deployments [6].

Just like VoIP, SIP phones provide many features that are unavailable with traditional landline telephony.

Common Features of SIP Phone Devices

A SIP phone, whether connected to a computer or smartphone, typically includes several basic features:

• Call forwarding
• Conference calling
• Call recording
• Caller ID
• Optional hold music
• HD-quality voice calls
• Incoming call customization
• Automated answering services
• Cross-platform integration with the SIP client

SIP itself supports capabilities including user location, availability, media negotiation, session setup, session modification, transfer, and termination [2].

Options and features vary by provider. Comparing available solutions can help you find the best combination of features and pricing.

Why Use SIP?

SIP can help businesses reduce their reliance on intermediaries and streamline their infrastructure. SIP telephony also allows companies to make full use of their existing Internet connection and benefit from more advanced features without disrupting employees’ workflows.

SIP provides a relatively simple path for moving a traditional telephone system toward an Internet-based setup. In the following sections, we’ll look at the other benefits of SIP in more detail.

The Benefits of SIP Calling

SIP calling services can be added to many different communication platforms. While this is one of SIP’s best-known advantages, it is far from the only one.

Here are the main benefits of SIP calling:

Lower Operating Costs

SIP connections allow you to make SIP calls through communication platforms at a more affordable cost. Say goodbye to per-minute call charges, required physical hardware, installation fees, maintenance costs, and service-related complications.

As long as you have a connection, you can make SIP calls.

Greater Scalability

As with any virtual service, deploying SIP is quick and straightforward. With SIP trunking, all your SIP multimedia communications can operate through a simple data connection.

SIP can establish sessions involving different media types, while session descriptions communicate information such as the media involved, transport protocols, addresses, ports, and formats [3].

Your service can scale flexibly depending on the features you use and how frequently you use them.

Unlike traditional telephony, which relies on physical equipment such as desk phones and landlines and may require installation costs and additional inventory, a SIP system provides a much more efficient alternative as your requirements evolve.

Increased Productivity

Unified communications can help increase workplace productivity. Data can be shared both inside and outside a centralized application or platform.

Employees can also improve productivity by bringing their communications together, potentially saving several hours of work each day.

Excellent Call Quality

The days of constantly worrying about Internet call quality are behind us. As long as you have a strong Internet connection, your call quality can be comparable to that of a landline call.

VoIP transmits speech over data networks, making network configuration, availability, security, and related infrastructure important considerations for reliable communications[5].

SIP trunking can reroute your calls to other devices or endpoints on the network, helping provide excellent call quality.

A Low Learning Curve

Moving to new technology can make even experienced employees uneasy. Because communications are centralized, SIP calls and their routing across the network are relatively easy to understand.

SIP technology also makes it easier to share data between teams and with customers through a centralized interface. Many SIP providers also supply documentation, support lines, or other ways to contact them if an issue arises.

SIP vs. VoIP: What Is the Difference?

Although SIP and VoIP are two different services, both allow users to make calls through Internet connections. Even so, there are significant differences between them. Choosing one over the other without considering your business requirements would be unwise.

VoIP refers broadly to transmitting voice over data networks[5], while SIP is an application-layer signaling protocol used to establish, modify, and terminate communication sessions [2].

SIP carries VoIP calls. While SIP calling can be used on a VoIP communication platform, the SIP protocol initiates VoIP calls.

SIP is not the only protocol that can enable VoIP. VoIP and SIP can work together when each service is optimized around the needs of your business. SIP commonly operates alongside other protocols for media transport, session description, and related communications functions [2].

VoIP offers substantial advantages for businesses of all sizes. Initial costs are low, ongoing costs are predictable and based on service usage, VoIP is portable and independent of a single device, and available features are as varied as the businesses providing these services.

How Does SIP Telephony Work?

SIP calling allows you to bypass traditional telecommunications networks and installations. With SIP, there is no need to rely on landlines or other conventional office telephone systems.

One of the main advantages of moving to a software-based solution such as SIP—although hardware-based SIP solutions also exist—is that mobility and portability have become essential to modern business success.

SIP supports user-location and redirection capabilities that allow users to maintain a consistent externally visible identity while communicating from different network locations [2].

Being able to communicate with customers, consumers, suppliers, and employees regardless of their location is a considerable advantage that traditional telecommunications systems cannot provide.

With SIP, you can even launch several sessions simultaneously and increase productivity.

SIP can also be used in less obvious ways, such as sharing files, scheduling meetings with integrated management software, or co-editing documents.

A Quick Overview of SIP Telephone Communications

Calls made over SIP begin with the sender. When the sender starts a call and dials a SIP number, the SIP server or provider receives a notification.

SIP call establishment typically involves messages exchanged between user agents and intermediary SIP servers, with an INVITE request initiating the session and subsequent responses establishing the result of the request [2] [4].

The SIP server sends the call to the intended recipient over the public switched telephone network, or PSTN.

The call is routed either through another SIP extension or by contacting that extension directly. Once the recipient receives the call, the connection is established and the sender can begin communicating.

Documented SIP call flows include direct user-agent communication, proxy-based routing, registration, session establishment, and interworking with the PSTN through gateways [4].

SIP servers assess call status and quality in real time. Additional steps may take place depending on the SIP provider you have chosen or the unified communications platform, such as VoIP, that you use.

SIP services can be software-based or hardware-based, depending on the options you choose from your provider.

How Do You Get Started With SIP?

SIP providers make setup and deployment relatively quick and straightforward. However, you still need a few things before you begin.

First, you need a SIP account. You can obtain one from any SIP provider.

Second, you need a SIP client. A client is an application for your computer or smartphone that allows you to use SIP calling features. Available clients vary by provider.

SIP endpoints, commonly called user agents, can act as clients when initiating SIP requests and as servers when receiving and responding to them [2].

Third, you need a data connection that allows you to access the Internet, whether through Wi-Fi or cellular data. Make sure your connection is reliable and that both upload and download speeds meet at least the minimum levels recommended by your provider.

Fourth, you need SIP communication equipment, such as a headset, microphone, webcam, and headphones. Choose these devices according to your personal and professional preferences.

Once you have completed these four steps, you can begin using SIP telephony.

Many VoIP service providers also support SIP calling. If you already work with a VoIP provider, ask whether SIP services are available. You may be able to skip some or all of the steps listed above.

What Types of Communications Can SIP Calling Support?

One of the first things any business leader needs to know when considering a new communication system is what the new solution can handle compared with the company’s existing setup.

For example, moving from a landline-only policy to a BYOD policy means recognizing that although employees have greater freedom to make calls wherever they are, BYOD policies are inherently less secure.

Personally owned devices introduce distinct cybersecurity and privacy challenges because businesses have less control over factors such as device configuration, software, access, and data handling [6].

IT systems need to be audited to reduce the risk of data leaks and potential network and device vulnerabilities.

The same principle applies to SIP: you need to understand what the system can do. Here is a short list of what a SIP system can provide:

• Caller and device location
• Multimedia communications
• Session management
• Simultaneous contact with multiple people
• Emergency calling services
• Rerouting services for improved call quality
• Internal calls
• Integration of SIP with other technologies
• Scheduling and data sharing
• Enhanced caller security features, such as call-quality monitoring

The SIP specification explicitly covers user location, user availability, media capabilities, session setup, session management, transfers, and termination [2].

Contact your SIP provider to find out which services are included in your contract.

Can Your Business Benefit From SIP Calling?

Businesses in every industry can benefit from SIP thanks to the system’s flexibility and versatility, particularly when extending VoIP services that a company already uses.

SIP calling allows businesses to:

• Collect more call data, which can be analyzed to improve team productivity
• Use free calling services
• Contact long-distance and international customers more easily
• Work from home or while traveling, since employees only need an Internet connection

Internet-based and mobile communication technologies can support remote access and flexible working arrangements, although organizations should apply appropriate security controls to remote and personally owned devices [6].

Let’s take a closer look at the advantages of adopting SIP for your business telephony and network infrastructure.

The Benefits of Unified Communications and SIP Calling for Your Business

Unified communications refers to a centralized communication platform, usually delivered through an Internet-based service or smartphone application.

Facebook Messenger is a good example of unified communications technology. You can message friends and call them by voice or video using a cellular or Wi-Fi connection.

VoIP services are another example of unified communications, particularly when they include SIP calling functions and features.

Unified communications and SIP calling offer two major benefits for businesses.

First, all communication methods are centralized.

Second, this centralization can help reduce operating costs.

Centralizing any service—not just communications—can be valuable for businesses.

If employees have to juggle several applications at once, enter information in one system, and call customers through another, information can be lost or fail to circulate effectively.

You need a communication system that allows you to save and access customer information, call customers, take notes, and manage internal and external business communications.

Centralizing systems can also reduce operating costs. SIP can be bundled with other services, and many communication platforms offer service packages at competitive prices.

Rather than paying several third-party providers for separate SIP services, you can choose a provider that combines those services at a competitive price. A penny saved is a penny earned, especially in today’s economy.

At this stage, you should have a broad understanding of SIP, how it works, and the benefits it can provide to your business.

Although every company may not make the switch, SIP remains a viable option for the future, whether your aim is to reduce operating costs, increase productivity, or move to a better business telephone communication service.

Looking for a SIP System? Ringover Can Help

SIP systems can provide significant benefits for your telecommunications setup, both in the office and on the go.

Ringover includes many services that complement SIP systems, including international calling, mobile applications, conference calling, and more.

Available as a cloud application, Ringover integrates with your existing business applications to help you optimize telecommunications in your daily operations.

As software developed specifically for business needs, it also includes supervision and performance-monitoring capabilities.

Want to find out what a SIP system could do for your business? Contact one of our SIP specialists today to schedule your demo.

Citations

• [1]https://d1.awsstatic.com/whitepapers/Industries/Telco/real-time_communication_aws.pdf
• [2]https://www.rfc-editor.org/rfc/rfc3261.html
• [3]https://www.rfc-editor.org/rfc/rfc4566.html
• [4]https://www.rfc-editor.org/rfc/rfc3665.html
• [5]https://csrc.nist.gov/pubs/sp/800/58/final
• [6]https://www.nist.gov/publications/mobile-device-security-bring-your-own-device-byod

Published on September 17, 2020.