What Is SIP Trunking?

Effective communication is a must for any organisation. Businesses depend on the communication network to perform their daily operations. Employees communicate via voice call, video call, or chat.

Most businesses run on legacy systems such as the Public Switched Telephone Network or PSTN. PSTN is based upon the physical telephone line system and uses the principles of a circuit-switched network. It requires a physical line between the two points to establish a connection.

For most businesses, PSTN gets the work done, but if you aim to achieve much more, SIP may be a breath of fresh air in your business. With each passing day, SIP Trunking is covering more ground. The technical support offered by SIP is unmatched, and you can get so much done. Most people and even businesses are unfamiliar with the concept of SIP trunking.

SIP Trunking meaning can be simply defined as communicating over the internet. SIP trunk full form is Session Initiation Protocol. It replaces the need for traditional telephone lines and works with an IP enabled Private Branch eXchange. To optimise your business communication, SIP upgrades your PBX to an internet-based phone connection system.

As further advancements in SIP technology come, you can revolutionise your business communication. Let us dive a bit deeper into the world of SIP Trunking and transmission over the internet.

What Is SIP Calling?

SIP's full form in the telecom industry is Session Initiation Protocol. An application layer protocol allows you to communicate over an internet connection using a phone system. SIP eliminates the need for a phone line to establish the relationship between two points.

If you are wondering what is the meaning of SIP, look at it as a virtual phone line connection. SIP calling allows users across the globe with a phone number to receive or make a phone call. Like a landline provider, a SIP provider offers a subscription to SIP trunking. Some SIP providers allow you to keep your PBX systems and transform them into an internet-powered phone system.

What Does SIP Stand For?

SIP stands for Session Initiation Protocol. SIP trunks enable users to make or receive calls using a packet switch network. Voice calls are first broken down into smaller digital packets to be sent across the network.

What is Trunking?

As the name suggests, trunking is a system where multiple branches are connected to a single trunk. It is a commonly used technique in data communication to provide access to multiple users using various lines or frequencies. It is also used in VHF radio and telecommunication systems.

Trunking is used to define a network that handles multiple signals simultaneously. It allows users to transmit data in audio, video, control signals or images. Trunking reduces the size of the telecom network and increases bandwidth. The connections are less dense as multiple users share them. It also improves the understandability of the network.

How Does SIP Trunking Work?

The session initiation protocol form is predominantly used in IP technology. It sets up a voice over internet protocol or VoIP over the internet to facilitate voice calls with other persons, multiple people on conference calls and video calls.

The SIP trunk is the intermediary between the phone systems and the internet telephony service provider. Previously, ISDN circuits were used that needed to be installed physically, and calls were sent through copper lines, whereas SIP uses data networks to transmit them.

The key components of SIP trunking include:

• Active Internet Connection
• IP-Box (SIP compatible PBX)
• VoIP phones/adapters
• Network connection

Legacy hardware systems require a SIP-ISDN gateway, but newer systems do not need this additional hardware. Communication over SIP is facilitated by codecs that convert the audio and/or video signals into digital packets for transmission over the data network. Some standards need to be maintained to ensure that data is sent and received correctly.

Two primary types of codecs are G.711 and G.729. They vary upon the compression.

• G.711- This codec requires more bandwidth at 128kb/s or 64 kb/s for each direction to make a call. The same codec is utilised by the PSTN network and offers excellent voice quality.
• G.729- This codec requires comparatively lesser bandwidth at 16kb/s or 8kb/s for each direction. While it delivers satisfactory voice quality, it does not compare to the higher bitrate codec.

Difference Between SIP and VoIP

SIP and VoIP are two different terms with distinct meanings. They are commonly used interchangeably but are not the same thing. SIP trunk full form is Session Initiation protocol, while VoIP stands for Voice over Internet Protocol.

VoIP is a broader term used to describe phone calls made over the internet. SIP can be understood as the subset of VoIP and is an example of VoIP protocol technologies. The difference between the two terms is in their scope.

Advantages Of SIP Trunking

As we enter a newer digital age, continuing the same old business practices may be detrimental to your growth. You have to achieve excellent business communication to stand out from your competition. SIP trunking offers many benefits to its users and simplifies the entire process. VoIP is less expensive and provides more growth opportunities to its users.

The following reasons are why many businesses are shifting from the traditional PSTN to SIP trunking.

Affordability

SIP trunking is cost-efficient and reduces a lot of overhead costs. You may be paying for lines you aren’t using with traditional phone lines. Also, long-distance calls and international calls are charged more. Add to it the cost of maintaining equipment and charges for additional connections.

On the other hand, SIP trunking offers simplified charging plans. Generally, you are charged on a per-user basis, so you need only pay for what you use. Based on your requirements, you may opt for a metered on an unmetered plan.

Virtual Connection

SIP Trunking creates a virtual world for employees and businesses where they can quickly post their availability. Messages and calls can be forwarded directly to your assistant if you are busy in a meeting. It’s easier for everyone to connect with each other as SIP trunking grants an address to each user.

Scalability

Technology and business go hand-in-hand. You need your technology to meet the requirements of your growing business at all times. Failure to do so will result in a failed opportunity for growth.

SIP trunking system is developed to facilitate rapid growth in your business. Its adaptive design is ready to incorporate new changes and new users into the system with ease. There is no need for new infrastructure or waiting on a service agent to add a new line. With SIP trunking, you can do almost everything on your own.

Reliability

SIP trunking prevails where traditional phone service is unavailable. Usual disruptions such as phone failure, bad weather, or damage to infrastructure are seldom reported with SIP trunking.

SIP trunking with VoIP offers enhanced reliability to its clients. It means that you will be able to use your phone even in case of a failure. Also, rerouting lines to other offices, numbers or devices is more manageable than physical phone connection lines.

Flexibility

SIP trunking offers a lot of flexibility features. Configurations are simple with SIP, and it provides low-cost migration from legacy devices. PRI is sold in increments of 23 channels, so you may be paying for additional channels. SIP trunking is embedded alongside traditional phone service, and you can request specific additional channels without a visit in a few hours.

Customer Support

SIP trunking platform offers tech support in case of any discrepancies. You can reach out to customer support with much ease. Solutions are provided quickly to avoid any business interruptions.

SIP Trunking Pricing

SIP trunking is much more affordable than paying for phone lines. The following factors affect the pricing of SIP:

• Fixed Monthly subscription
• Call rates
• Add-ons
• One-time charges

The one-time charges need to be paid once at the beginning of the service as activation fees. The fixed monthly subscription charges are priced per channel of the voice service and are charged on both metered and unmetered plans. Outbound call rates are charged per minute on metered plans. Businesses can also opt for special add-on features such as auto-reply assistant, call recording, etc.

The primary feature of SIP trunking is affordability and keeping your phone bills under control. Depending upon your SIP provider and the plan you choose, you will be able to cut down costs. Your SIP provider will move all your communications to the cloud without new infrastructure.

SIP trunking offers low cost and better call quality even if you are running concurrent outgoing and incoming calls. Two primary approaches for a SIP trunking plan are as follows:

• Metered Plans: Monthly Fees and per-minute charges for outgoing calls.
• Unmetered Plans: Monthly fees and Unlimited calling ( for a fixed charge)

SIP Trunking V/S Primary Rate Interface

SIP trunking and PRI are the two primary modes of phone connection systems. They are often compared to each other to understand their feasibility for a business. Let us compare both of them to help you decide which one may be better for your requirements.

Implementation

PRI uses physical lines to establish connections, whereas SIP trunking uses a data network to transmit digital packets of information.

Implementation of PRI is a lot of work as it requires a lot of planning and execution to install a working line physically. SIP trunking works on the principles of VoIP to offer phone connections over the internet.

Quality

PRI lines offer high-quality audio when running on dedicated lines. PRI makes sense for businesses with insufficient bandwidth and limited access to a fibre-optic network. Phone lines may suffer in case of a power outage due to bad weather conditions.

If you have sufficient bandwidth, SIP service will remain high quality with more flexibility in case of discrepancies. ISPs have excellent uptime, but your phone calls may suffer in case of an internet outage.

Upgrades

Upgrading your PRIs are expensive and not easy to implement. You will have to add new lines for more channels physically. The entire process could take over a month as your service provider will conduct an on-premise visit, and you will have to go through lengthy contracts.

SIP prevails here as you can request an upgrade, and the new channel will be installed within a few minutes or hours.

Cost-effectiveness

SIP trunking is more affordable than PRIs. You get a lot of cost benefits with SIP trunking, such as free calls on the same VoIP system and better international call rates than PRI.

Security

PRIs do not require network security needs such as firewalls which is a desirable additional security feature with SIP trunking.

SIP Trunking V/S Hosted PBX

If you consider other VoIP options such as Hosted PBX, slight differences exist between them and SIP trunking. Let us discuss them in detail.

• The initial setup cost is low in both systems if you have on-site PBX equipment or SIP trunking equipment.
• SIP trunking and Hosted PBX offer similar call rates.
• Your provider will maintain the system in the case of PBX, but for SIP, your internal staff will have to handle it.
• SIP trunking handles high volume calls better than hosted PBX.
• SIP trunking offers additional security features over hosted PBX.

Hosted PBX systems may work well for small businesses with lower concurrent calls, but businesses with more than 20 employees should opt for SIP trunking.