Close Button
Book a discovery call

What is SIP Communication? Everything You Need to Know

$500k+ for a custom softphone app?
Compare your options, costs, and other key factors by downloading our new ebook.

SIP communications isn’t a new type of technology. It’s been around for well over a decade by now. So, why are SIP communications so popular within the business world?

Today – high-quality communications are the standard. Whether you’re a business or an individual, you expect nothing but the best when making a call.

Many companies are turning to Session Initiated Protocol (SIP) apps to accomplish this. Read on to learn more about SIP and how it enables essential functions for VoIP communications.

What is Session Initiation Protocol or SIP?

Session Initiation Protocol (SIP) is a flexible protocol used in VoIP platforms to initiate and manage call sessions. SIP is considered a call initiation protocol, but it can do much more than initiate voice calls. SIP also has enhanced functions that make it powerful throughout communications environments.

The Five Major Functions of SIP

SIP handles several functions that make it a core protocol in VoIP services, understanding these 5 terms will give you the necessary tools to better understand the technology. SIP needs flexibility and versatility to meet the demands of VoIP communications platforms. Engineers consider SIP to have five distinct significant functions:

  1. User location and registration: Endpoints leverage SIP proxies to register locations, and SIP uses this information to determine which endpoints will participate in a call, including video calls.
  2. Session management: SIP can terminate calls, transfer calls, or change call parameters, such as adding another user.
  3. Session setup: SIP is used to agree on specific session attributes used by both the called party and the calling party, including telling the called party’s endpoint that it needs to ring.
  4. User availability: Is the called party available to answer the call? SIP can tell the calling party that the user they’re calling is available or unavailable.
  5. User capabilities: SIP supports multimedia communication, so both endpoints must agree on the codec that needs to be used, such as the voice codec.

These functions are used throughout most VoIP calls to enable multimedia and dynamic communication.

SIP technology also enables SIP trunking, a service that allows on-premise PBX networks to connect to VoIP services for outbound calls rather than being restricted to traditional telephony networks.

That old phone you used nearly 15-20 years ago could make calls, maybe it had voicemail if you paid for it, and caller display. You also had to pay an insane amount of money to make long-distance calls. It was pretty basic and couldn’t do much.

What about today? Your smartphone is a sophisticated device that uses your Internet connection to seamlessly integrate web, email, instant messaging, and other services through your IP network. You can instantaneously call anyone from anywhere in the world for free.

SIP phones provide the architecture through a platform that makes all of this possible.

Today – everyone is using them. You may not know it, but your phone carrier has one integrated, apps like WhatsApp and Skype are SIP apps, many companies use them for communications, even creating their own custom solution with our white label VoIP softphone design tool, and many more are rushing to get their own internal SIP phones developed.

When Was SIP Technology Invented?

What Is Session Initiation Protocol

SIP technology was originally invented by Mark Handley, Henning, Schulzrinne, Eve Schooler, and Jonathan Rosenberg in 1996. The technology itself was standardized as RFC 2543.

By 2000, it was accepted as a 3GPP signaling protocol for IP Multimedia Subsystems (IMS) architecture for IP-based streaming in cellular networks.

While today SIP technology is widely used in the telecom industry, it started as a practical solution for IP-based communications. In the early days, it was used for things like:

  • Video conferencing
  • Streaming media
  • File transfer
  • Internet fax
  • Instant messaging
  • Online gaming

How Do SIP on a Phone Work?

Internet telephony has simplified the way we communicate with each other. Long-distance calls are a thing of the past, thanks to the Internet. SIP phones can be implemented as either hardware or as a software phone, commonly called softphone.

But how does SIP make all of this possible, and what is a softphone? SIP technology acts as a middleman between you (the caller) and the person you are calling. Your SIP app will handle the entire process so long as both parties have access to a stable Internet connection, all possible with a softphone app.

In both traditional and IP telephony, network engineers distinguish between two phases of a voice call:

  • Call setup: This phase includes all the details necessary to connect two phones to each other.
  • Data transfer: Once connected, the data transfer phase moves voice packets between the two endpoints.

SIP is classified as a call setup protocol that operates on the application layer. SIP was designed as a general-purpose protocol that enables real-time multimedia communication.

This vital protocol was designed for simplicity. SIP is text-based and modeled after HTTP’s response and request model. The text-based nature of the protocol enables easy debugging and reviewing of error logs. Additionally, SIP can operate on IPv4 or IPv6 and can use either TCP or UDP. In most applications, SIP uses IPv4 and UDP.

Here’s a brief explanation of the process in more relatable terms:

  • You call a friend using your SIP phone. Just like a normal phone, you’ll hear ringing as you make the call.
  • Your voice and video are converted into a series of encrypted data packets that are transferred to your recipient. Their SIP app receives the data, instructions on how to access it, and converts it into multimedia that they can hear. This entire process happens in milliseconds.
  • When the call is terminated, the connection between you and your recipient is terminated as well.

What Is SIP Trunking and How Does it Work?

SIP Trunking is like a modern phone line for businesses, but it works over the Internet. Instead of using old phone lines, it uses a business’s computer network to make and receive calls. SIP changes the sounds of a call into digital signals that travel online.

How do businesses benefit from SIP trunking?

It’s good for businesses because it can handle many calls at once, is cheaper than old phone systems, and adds cool new features. Each call uses a ‘channel’, and businesses can have many channels on one SIP Trunk to handle lots of calls at the same time. SIP Trunking can do a lot of things, like keep calls private, follow emergency call rules, be reliable, work with cell phones, and show how well it’s working. Businesses can talk to SIP Trunk providers to learn more and see what special things they offer.

Replacing traditional telephone lines, SIP works with a business’s Private Branch Exchange (PBX) and allows the use of virtual phone lines that can dial phone numbers and make and receive phone calls over the Internet. It does so by converting analog voice audio into a digital signal that gets sent online.

SIP can create, manage, and terminate communication sessions between parties in an IP network. Those sessions can be either two-way or multi-way for a conference call.

Management teams are interested in SIP because it connects a PSTN network with on-site VoIP phone systems. This way, the cost of keeping legacy communication platforms is lower, and you get the chance to add in some modern features as well.

What Is a SIP Trunk Channel?

A channel is essentially any incoming or outgoing call. Every SIP trunk is capable of supporting multiple SIP channels. A business is capable of running on a single SIP trunk and scales its number of channels based on how many concurrent calls it expects to use.

What Does the SIP Trunking Architecture Support?

The features that SIP trunking enables are numerous and add to the appeal of working with a SIP trunking provider.

  • 911 routing for legal compliance
  • DoS protection for reliability
  • Interoperability with cellular networks to enable call forwarding
  • Usage reporting to measure performance

These are only a few examples of what some SIP trunking providers can offer. Get in touch with a few on your list to find out what else could be in store.

How do you Choose a SIP Trunking Provider?

A SIP provider acts as the glue between your on-site IP-enabled PBX system and your traditional PSTN phone line. An experienced vendor knows how to tailor the system to the individual needs of your business rather than just throw you an “off the shelf” solution.

When looking for a service provider, look for these signs of a good one:

  • Reliability: through redundant call routing or a failover system. You don’t want an outage or network failure to knock out your ability to collaborate.
  • Data security: this is especially important today in the age of cybersecurity risks and data breaches. Business communication often involves the sensitive personal information of customers and staff, so make sure there are protections against fraud and cyberattacks.
  • Data analytics: that can help you improve your customer service or optimize internal operations in real time.
  • Technical support: through documentation or troubleshooting assistance. In case you ever have a problem, it’s good to know you’re in good hands.

Finally, don’t forget to think about the pricing model, specifically the contract you agree to when you sign up. What’s the monthly fee? Is there an upfront charge? And what does the cancellation policy look like?

What’s the Difference Between SIP & VoIP?

VoIP and SIP may seem like competing technologies, but they are part of the same family of technologies enabling IP-based communications. VoIP is the umbrella term for a collection of protocols, including SIP. SIP is the call setup protocol that enables other VoIP protocols.

Why Should My Business Switch to VoIP through SIP?

The average VoIP app on the market is capable of making calls but doesn’t do enough to personalize the communications experience. One of the major SIP trends is to empower businesses with several meaningful benefits that are often attributed to VoIP, but are actually enabled by SIP. Some of these benefits include:

  • Easily scalable: SIP systems are entirely Internet-based. As broadband has penetrated most of the world and fiber optic cables have replaced copper wires, SIP can scale as needed to meet the demands of large enterprises and small businesses alike.
  • Cross-device compatibility: Since SIP works over the Internet, it can operate on mobile devices, laptops, desktops, and tablets. Employees can use any device they need, and SIP will dynamically understand which device needs to ring when receiving a call.
  • Baked-in redundancy for reliability: If a traditional telephony network has an outage, there generally isn’t any redundancy, and businesses need to wait for the network to undergo repairs. Conversely, SIP calling leverages geo-redundant cloud-computing technology for substantially improved reliability. This redundancy provides improved reliability for VoIP services over traditional telephony services.

White-label SIP phones are capable of personalizing and customizing your real-time communications experience. This means more flexibility, more cost savings, and the ability to include the features that matter the most to you.

The right SIP app will save your business a lot of time and money, improve employee productivity, let you tap into detailed mobile analytics, and provide a seamless communications experience.

Want to learn more about our White-label SIP platform? Talk to our team today!

Recommended For You
SIP and AI: Integration of Artificial Intelligence and Unified Communications
SIP and AI: Integration of Artificial Intelligence and Unified Communications

Unified Communications-as-a-Service (UCaaS) providers must stay aware of trends affecting how people communicate and the overall IT landscape. One of the most significant trends shaping the future of IT is artificial intelligence (AI). The global artificial intelligence (AI) market is expected to skyrocket from roughly US$100 billion in 2021 to $2 trillion by 2030. Generative […]

read more →
The Evolution of SIP: 4 Trends and Future Outlook
The Evolution of SIP: 4 Trends and Future Outlook

SIP has skyrocketed in growth alongside the need for dependable and scalable telecommunications. As a result, enterprises and individuals alike are using VoIP and SIP services daily, allowing for higher-quality voice calls and robust capabilities to meet the needs of the modern world. Over the past decade, we’ve seen Session Initiation Protocol (SIP) clients go […]

read more →
Securing SIP: Best Practices for Protecting Your Communication Infrastructure
Securing SIP: Best Practices for Protecting Your Communication Infrastructure

Session Initiation Protocol (SIP) is a robust protocol that enables businesses to run phone systems over the Internet. The rapid adoption of SIP has allowed for organizations of all sizes to establish more dependable and scalable communication systems. Analysts expect the global SIP trunking services market to reach US$43.74 billion by 2031, a substantial increase […]

read more →
Maximizing SIP Benefits in 8 Key Industries [2024 Guide]
SIP Softphone
Maximizing SIP Benefits in 8 Key Industries [2024 Guide]

The market for Voice over Internet Protocol (VoIP) services have been growing globally for many years now. Having been spurred on by the pandemic and various other factors involving digital transformations in modern business, VoIP is projected to be worth $194.5 billion by 2024. It’s clear that there’s a significant demand for VoIP and SIP […]

read more →