What is SIP?

The Session Initiation Protocol (SIP) is a communications protocol for signaling and controlling multimedia communication sessions. The most common applications of SIP are in Internet telephony for voice and video calls, as well as instant messaging all over Internet Protocol (IP) networks.

The SIP protocol defines the messages that are sent between endpoints, which govern establishment, termination and other essential elements of a call. SIP can be used for creating, modifying and terminating sessions consisting of one or several media streams. SIP is an application layer protocol designed to be independent of the underlying transport layer. It is a text-based protocol, incorporating many elements of the Hypertext Transfer Protocol (HTTP) and the Simple Mail Transfer Protocol (SMTP).

What is SIP Trunking?

In simpler terms, SIP Trunking was developed to allow both voice and data to be transmitted over the internet at the same time. It enables organizations to place telephone calls over a WAN connection which would then connect to Public Switched Telephone Network (PSTN). SIP behaves as an application on your network and requires either an Internet connection, or a VoIP vendor, plus an IP-enabled PBX, and a border element or gateway to support IP-based voice communications.

However, it’s not as simple as relying on the internet to ensure everything operates smoothly. Despite the growth, data breaches and interoperability issues can plague SIP trunking services when not researched and tested properly. The smooth functionality of SIP trunking and its call quality relies on ensuring that service providers, edge device vendors, and IP-PBX all work harmoniously. If not, expect to experience functionality issues, including call quality problems, delays, dropped calls, and jitter.

SIP Trunking Is On the Rise

With the exponential growth of VoIP, it’s only natural that the SIP trunking services market is rising with it. Expected to reach US$20.70 bn in revenue by 2024, rising from US$4.47 bn in 2015 in North America, Europe, and the Asia Pacific, companies around the globe are making the switch from MPLS and PRI during large-scale migrations to IP networks. Low cost and increased flexibility are the main factors driving SIP adoption.

6 Advantages of SIP Trunking

SIP TrunkingAs a text-based protocol, SIP keeps it pretty simple. The scalable, easy and fast implementation of SIP trunking requires far less time than its predecessor protocols and delivers real-time sessions when and where you need. As a peer-to-peer protocol, it doesn’t require implementation at the network level. Instead, the logic is applied at the communication endpoints. But how does that actually translate into tangible benefits? Let’s explore:

1. Cost Savings of SIP Trunking
As the perennial benefit to technology improvements, cost savings is one of the leading advantages of SIP trunking. By removing the need to manage and maintain separate networks and the associated hardware and software, costs can be greatly reduced.

More specifically:

  • Paying on a per-user basis, rather than line-item fees for local, long distance, and international calling. With predictable monthly rates, businesses can save 50% each month (or more for businesses with a large volume of long distance and international calling).
  • Eliminating the need to purchase Primary Rate Interfaces (PRIs) or local PSTN gateways to lower costs.
  • Connecting directly to the chosen IP service without requiring a subscription fee.
  • Relying on a connection over the internet, so that services can be added or modified fast and easily, unlike with traditional PSTN and PRI lines. This allows for a “pay as you go or grow” model, where business owners can pay on a quarterly basis, as need and budget become available.

2. Automatic Call Failover At Anytime
One of the biggest advantages to any business that relies heavily on their ability to communicate with outside customers (such as a Contact Center or remote worker) is SIP trunking’s ability to guarantee automatic call failover.

There are many components involved in routing calls between users and any business continuity plan should account for failure in one or more of these components. For instance, hardware failure can occur at any time, especially with heavy traffic on the network and calls being routed to different locations. Components such as IP servers, session border controllers, the enterprise LAN/WAN, routers, IP phones etc. can fail, causing a service disruption.

In order to ensure that the SIP trunks failover gracefully – if something fails – the SIP trunk automatically finds an alternate destination for the failed call. The alternate destination may be a mobile number or another SIP trunk. The “load balancing” features of SIP trunking ensure that call load is allocated to a different channel to ensure that no single trunk reaches hundred percent utilization. Therefore load-balancing is a good option even during normal business hours to ensure consistent and constant voice services.

3. ROI You Won’t Have to Wait For
In the digital transformation, businesses of all shapes and sizes find themselves jumping into technologies that don’t have clearly defined return on investment (ROI) paths. A common example is cloud storage where businesses just assume computing power is cheaper, without giving full attention to security implications, changing product matrices, and disaster recovery. In these types of technology investments, it may take years before organizations achieve a positive ROI.

Newer technologies may have the “shiny” factor, but SIP trunking has the advantage of being a well-established technology. With minimal upfront investment costs, businesses won’t have to swallow large CapEx bills that can degrade starting margins. Instead, organizations that switch to SIP will experience cost savings from the first monthly bill.

4. Unshackled from Infrastructure
Ultimately, traditional phone services can no longer keep pace with modern businesses. Lengthy wait times for installation of new phone lines don’t align with the instant gratification mindset and the pace of business. And really, organizations shouldn’t be held back from growing. SIP trunking unshackles businesses by allowing phone lines to be added by just connecting handsets to the existing data connection and scaling the monthly service agreement.

If a company wanted to hire an employee on the other side of the world, it’s easy to integrate that person into the company network and have them reachable with a dedicated internal phone number and five-digit extension. No wait times. No large hardware investments.

5. Reliability, No Matter What

For organizations in areas that frequently experience hurricanes, floods, or other natural disasters, reliability is one of the first questions asked when exploring a new service. They understand that for one reason or another, service can be interrupted, and so will their business. The fact of life is that things happen – and it’s not just big weather events that can cause a ruckus.

SIP trunking offers a high level of reliability by offering mobile-failover as a form of redundancy. In the event of a failure or outage, calls can be re-routed to alternate offices or mobile devices so that every day is business as usual, no matter what the circumstances. Not only does that improve the user experience, it also shows a high level of professionalism to customers.

6. Management Just a Click Away

Sure, hold music has improved over the years, but would employers rather IT call into a queue to troubleshoot connectivity issues or dedicate that time to pressing initiatives that impact the bottom line? Probably the latter. SIP trunking and VoIP phones free precious time by providing a single pane of glass administrative portals for on-site management, including adjustments to call routing, assigning or changing extensions, and adding phone lines on-demand.

Is a Switch to SIP Trunking the Right Choice for Your Company?

With a laundry list of benefits that can be applied to a multitude of use cases, SIP offers a few disadvantages compared to alternatives. If you’re considering a switch to SIP trunking, start by asking:

  • Does my organization struggle with confusing phone bills?
  • Are we plagued by unreliable phone lines?
  • Is balancing on-site phone lines with mobile devices becoming a struggle as employees work outside of the corporate network?
  • Do we need to reduce and consolidate our high calling costs into a predictable monthly rate?

Answering “yes” to any of these questions indicates SIP trunking could be the right fit – along with sufficient data connectivity bandwidth to ensure it works seamlessly as promised.

Rely on Expertise to Make the Switch to SIP Trunking
Before planning on SIP trunking as part of a larger on-premise VoIP solution, most organizations will need to seek help from experienced telecommunications professionals. As in any other technology change, there are many factors that should be taken into consideration (e.g. up-front capital investments for equipment and interoperability testing). A bit of planning will ensure that you reap the benefits that SIP trunks offer without any disruption to your business.


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