Business phone system providers often hear the question: “How many SIP trunks do I need?” The answer depends on several factors. Find out how SIP trunks work so you can make an informed decision about your communication strategy.

Below, you’ll learn about the basics of SIP trunking. You’ll discover the number of channels in a SIP trunk. After that, you can explore some of the technical requirements and examine how the information relates to your business needs.

First, What Is SIP Trunking?

Session initiation protocol (SIP) trunking is the virtual connection between a business and an internet telephony service provider (ITSP). It transforms telephone communication within an organization.

Trunking makes it possible for business phone systems to operate over a network connection, as opposed to a traditional phone line. Instead of relying on traditional phone lines, a company can easily deploy and scale a virtual system. SIP trunking works in correspondence with a VoIP connection, turning your VoIP phone system into a virtual phone network.

What Are the Benefits of SIP Trunking?

Businesses use SIP trunking for various reasons. Here are the main advantages of implementing a SIP system:

Cost savings: Traditional phone or PRI (primary rate interface) networks can be expensive since they deal with actual physical hardware. But SIP trunking relies upon a virtual connection, making it easy and inexpensive to add more lines. Plus, you’ll only pay for the number of lines you use instead of getting locked into larger packages. SIP trunking leads to cost savings across the board

Easy scalability: Since SIP trunking relies on a virtual connection, you can add lines and modify your service quickly. You can scale up as your business expands or scale your service down during slow seasons

Unified communications: SIP trunking allows you to easily transfer calls between multiple business locations. This will help you provide a cohesive experience, even when your business is spread out across the globe

Improved reliability: Since SIP trunking relies on a virtual network, there's no single critical point of failure. You'll have multiple different options for call answering and routing if an issue does occur

The Difference Between SIP and VoIP

The terms voice over internet protocol (VoIP) and SIP are often used interchangeably, but they are not the same. The simplest explanation is that VoIP is a service that enables you to send and receive phone calls over the internet. SIP is an application layer protocol that sets, changes or cancels multimedia communications, including VoIP.

SIP enhances VoIP by enabling communications beyond mere voice calls. Exchanges can then be made with multiple forms of data including video, files, messages and more.

How Much Bandwidth Does a SIP Trunk Need to Operate?

While SIP is a modern, convenient approach to business communication, there is one main challenge. Users will need a fast and reliable internet connection to get the most from their system. So how much bandwidth do you need?

First of all, you need to look at how VoIP communication works. As a conversation takes place, a codec (coder-decoder) first translates audio data (voice) into digital information. Then, the digital information is converted back to audio as it is sent across the line.

Insufficient bandwidth can lead to excessive latency or voice delays and dropped calls. A poor IT setup leads to an overall inefficient communication system.

SIP providers work with various codecs to translate communication data. Depending on the codec employed, you will need between 30 Kbps and 90 Kbps of bandwidth.

● G.729 codec for compressed toll-quality calls requires 30 Kbps bandwidth. Use this codec to save bandwidth with slightly lower voice quality

● G.711 codec for standard toll-quality calls requires 90 Kbps bandwidth. This codec is employed for typical calls without voice compression

● G.722 codec for HD voice quality calls requires 90 Kbps bandwidth. For the best sound quality, this codec is used

Depending on your provider, you should be able to choose your preferred codec from the SIP system dashboard.

Next, What Are SIP Trunk Channels?

Traditional telecommunication systems relied upon physical hardware. A trunk would be wired from your business to your telecom provider of choice. Within each trunk were different channels that could be used for calls.

Today, with SIP channels, this process has evolved into virtual networks. With a SIP trunk, you utilize virtual trunks, and each trunk has multiple SIP channels within it. SIP channels can be thought of as telephone lines where each channel supports a single phone call.

SIP Lines vs. SIP Channels

Sometimes you’ll see SIP lines used interchangeably with SIP channels. A SIP trunk acts as a container, while a SIP channel is a “line” where the simultaneous calls will travel. The terms line and channel have the same meaning.

How Many Channels Are in a SIP Trunk?

One of the most common questions that comes up concerning SIP is: "How many channels are in a SIP trunk?" There is no universal answer to this question. Every provider differs, so the number will change accordingly. Some providers will only be able to support a few channels per trunk, while others will be able to support dozens.

Most providers allow you to add or remove channels at any time. This means you won’t be locked into a set number of lines.

Now, How Many SIP Channels Does Your Business Need?

The number of SIP channels your business requires depends upon the number of calls you'll need to make at the same time. Look at your overall call volume and the number of concurrent calls that tend to occur. Doing so will help you determine how many SIP channels you need.

You need at least one SIP channel for every call happening at a given time. For example, 50 simultaneous calls will require 50 channels. The more your company grows, the more calls you will send and receive. As a rule, large companies will need more SIP channels than smaller businesses. However, this isn't always the case. Some businesses do most of their communication via email, live chat and other channels, no matter their size.

Ask yourself how many calls your company sends and receives on your busiest hour. The answer to this question is the answer to how many channels you need.

Finally, How Many SIP Trunks Do You Need for Your Business?

You will first need to check with your provider to find out how many channels are offered with each SIP trunk. By understanding the number of channels per trunk, you can make an informed decision. Hence, you ensure that you can always handle your call volume.

The total number of trunks required depends on the number of concurrent calls your business needs to make. If your provider offers 20 channels per trunk and you run 15 simultaneous calls at any given time, one trunk will suffice. If you run 100 simultaneous calls with the same provider, you will need at least five trunks.

Your SIP provider can work with you to determine the proper number of channels for your communication system. With the flexibility of a SIP system, you can scale this up or down as your call volumes change. In most cases, your contract will not be set to a specific number of trunks or channels.

What Happens When You Don’t Have Enough SIP Trunks for Your Organization’s Call Volume?

When there are not enough trunks to handle your call volume at any given time, callers are simply not able to get through. For example, imagine that you have two trunks with 20 channels each. On a random Wednesday afternoon, you receive a higher-than-normal amount of calls, and your 40 lines are all tied up. When the 41st caller and any others thereafter try to connect, they will be met with a busy signal.

Then, they will have to try to call back later and hope that a line has cleared. You're already off on the wrong foot with that customer. For one, they will feel that they can’t depend on you. Furthermore, you give your competitors a chance to help your customers solve their problems. Sufficient SIP channels will ensure you're ready for every customer that calls.

Get Your SIP Plan Right With 8x8

Knowing that you have enough trunks to handle your communications will save your business time and money. An efficient SIP system can enhance your productivity and customer satisfaction.

You now have all the information to determine the right number of SIP trunks for your business. All you need is the right provider. Take advantage of the knowledgeable staff at 8x8 to choose the right SIP plan to grow with your business. Whether you're an individual, a small to midsize business or an enterprise company, we can get you exactly the features you need. Plus, we enable you to leverage reliable and clear communication from any device.

Choosing the right technology is crucial to a growing business. Take the uncertainty out of the equation by choosing a SIP technology provider that can scale to meet your business' needs, whatever they may be at any given time. Call 1-866-879-8647 or fill out the form below to request a no-obligation quote from an 8x8 product specialist.

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