The advantages and disadvantages of SIP trunking

Phones are essential for most businesses, so there comes a time when you have to choose between ISDN and SIP trunks for connecting to the PSTN and wider world.

Choosing the wrong option can be very costly for your business, so it’s important to make the right decision now.

Do you know whether or not SIP trunking is the right option for your business? If not, this blog post is written to help you. I wrote this blog post to take about the advantages and disadvantages of SIP trunking, so you know everything you need to know about the technology.

What Is SIP Trunking?

A SIP trunk is essentially just a direct replacement for an ISDN line. In a traditional business telephone system setup, ISDN lines would connect your PBX to the PSTN (public switched telephone network). SIP trunks are in essence a virtual replacement for these physical lines.

An image showing how SIP trunking works.

A SIP trunk is a virtual line between your PBX and the PSTN or your VoIP provider. The connection is made using your data service. So instead of having voice and data services into your building, you only have a data service.

An interesting fact to know is that a ‘trunk’ previously referred to a bundle of phone lines shared between users. This ‘trunk’ enabled every phone to connect to the PSTN so phone calls were possible. So a SIP trunk works very much in the same way. While it isn’t a physical bundle of phone lines, it connects every device capable of making calls in your office to the outside world using your internet connection.

Now we’ve recapped what SIP trunking actually is, why don’t we take a look at the pros of investing in SIP trunking?

SIP trunking advantages and disadvantages: Advantages

Before modifying your PBX and implementing any new telecommunication solutions, it’s important to know the pros and cons of the technology. First and foremost, let’s take a look at the advantages of using SIP trunking.

Consolidated Network

One of the key reasons to choose SIP trunking over ISDN is the fact you’ll have a consolidated network if you do. Consolidation in this context basically means merging your networks. So instead of having separate voice and data services, you’ll only have a data service that you can utilise for your voice communications.

The advantages of consolidating your voice and data services.

The benefits of having a consolidated network are numerous, for example:

  • Your power costs will be lower
  • There are fewer components to manage
  • Your technology will scale easier with your business

If you’re currently using ISDN, you’re paying for your voice and data services separately. Not only does this mean more expense, but it means more management as well as more hardware.

With SIP trunking, your data service is used for your voice communications too. When you are using VoIP to make calls, your voice signals are digitised and transmitted as data packets using your internet connection, before being reassembled at the endpoint (the other user’s phone). So when using VoIP and SIP trunks, you still have a fully functional telephone system without paying for a costly voice service.

Lower Ongoing Costs

The ongoing cost of using SIP trunks is usually much lower than the ongoing costs associated with using physical phone lines.

Depending on the provider that you choose and the number of SIP trunks you need, SIP trunks can reduce your monthly phone bill by around 50%. Why?

SIP trunks are virtual, which means no physical infrastructure to maintain. With any type of physical infrastructure, there are ongoing maintenance costs. With SIP trunking, you don’t have to worry about maintaining lines or equipment.

Furthermore, calls made possible with SIP trunking use the internet – which you’re already paying for – rather than a separate voice service. Once you move over to VoIP and begin using SIP trunking, your monthly outgoings will immediately reduce substantially.

Easier Scaling In The Future

A traditional phone system really limits the growth of your business. Many business owners will remember the days of deliberating over investing in a second ISDN30 connection because they needed more capacity. Unfortunately, this is just one of the problems that prevent a traditional phone system growing with a business.

SIP trunking and VoIP are technologies developed with the future in mind. As SIP trunking uses your existing internet connection, you won’t need to invest in new lines in the future as you require more capacity.

Because using SIP trunking consolidates your voice and data into one network, your telephone system will grow easier and cost-effectively as your demand does.

We all dread having site visits from engineers. Why? Because they’re so expensive! That’s why it’s also worth mentioning that an IP PBX can often be modified remotely. Changes can be made and new users can be added without an engineer needing to visit your location. Furthermore, some providers can increase your concurrent call capacity without a site visit.

Easier Management

Managing ISDN lines isn’t just something that anyone can do. If you don’t have an in-house IT team, you would need to get in an engineer every time you need some assistance. Not only can this be very costly, but you can end up waiting a while for an engineer to come and manage your system. Even something as simple as adding a new user could be an expensive task that took a long time.

While SIP trunking and VoIP might sound confusing and seem complex, they’re both relatively easy to manage. Whether you’re from a telecommunications background or not, you’ll have no problem adding phone lines, extensions, features and so on. SIP trunking and VoIP is normally managed through a intuitive portal that makes adjusting your system simple.

If you do need to modify your system in some way and you cannot do it yourself, most changes can be done remotely by your VoIP provider. This can save your business a fortune because remote support is often much cheaper than onsite support. In fact, many VoIP and SIP trunking providers will bundle remote support costs in with the price you pay every month. So it’s possible you won’t have to pay a penny if you need support!

SIP trunking advantages and disadvantages: Disadvantages

Now we’ve had a look at the advantages of SIP trunking, it’s important to look at the cons too. Before making your decision on SIP trunking, here are a few cons to keep in mind.

The main disadvantages associated with using SIP trunks.

Not All Providers Are Made Equal

While SIP trunks can save your business a large sum of money and enhance your communication capabilities, they can also hold you back if you choose the wrong provider.

Some providers will offer a high-quality service that you can rely on; a service that will benefit your business massively and save you money. On the other hand, some providers will charge over the odds without any service guarantees and leave your business with a solution that doesn’t work.

Choosing the right provider for your business is tough, but here are some tips for finding an appropriate provider for your company:

  • Read reviews of providers you’re interested in: If you can’t find any reviews or the company has a lot of negative reviews, look elsewhere. One of the best places to look for reviews is Google. Search the provider’s name and a listing should come up at the side with reviews of the company’s services.
  • Read the provider’s terms and conditions: It’s always good to read through the provider’s terms and conditions before agreeing to anything. Remember that you will have to sign a contract with your chosen provider, so you need to ensure you are happy with what their terms and conditions say.
  • Know your needs before looking: Before looking for a provider, know exactly what you’re looking for. For example, how many calls you will be making concurrently. Some providers won’t offer what you’re looking for, others won’t have the capabilities to support your business. That’s why it’s so important to know your needs before looking!

Compatibility Issues

Is your current telephone system capable of integrating with SIP trunks in its current form? This is a question you need to know the answer to because it will impact how much moving over to SIP trunks will cost your business.

Is your current telephone system an IP PBX? If it isn’t, you can’t start using SIP trunks just yet. This may or may not mean that you need a new telephone system. It really depends on the telephone system that you have and whether it can be adapted to work with SIP trunks rather than ISDN lines.

If you don’t have a SIP-based PBX at the moment, it isn’t the end of the world. SIP trunking can be provided on a PBX that isn’t SIP-based using a SIP gateway. The gateway connects to your PBX via the analog or digital trunk ports. This piece of hardware then converts the calls as they leave your telephone system.

Using a SIP gateway is a great way of IP-enabling your existing telephone system. You can save your business the expense of having to invest in costly hardware all over again.

Good Bandwidth Needed

Only having one network to manage is one of the biggest advantages of using SIP trunks. However, it’s also one of the biggest downsides if you don’t have enough bandwidth.

If you’re going to move over to IP telephony, having a reliable connection with enough bandwidth is a must. If you don’t have enough bandwidth, you will run into numerous issues including calls dropping and poor voice quality.

Fortunately, good providers will ensure your connection is suitable before setting up SIP trunking and VoIP for you. And if your current connection doesn’t cut the mustard, they’ll advise that you need a better data service.

If upgrading your connection isn’t possible because of costs or other limitations, there are ways around the issue. For example, it’s possible that your provider can install a second connection for SIP trunking and VoIP alone. With a second connection, you will have guaranteed voice quality and support for the number of concurrent calls you need to make.

Need help? This is a free service for Business Tech Planet readers. Pop in your problem below and we'll be in touch soon!

Jack Mitchell

Jack Mitchell has been the Operations manager at telecoms and MSP Optionbox for more than 4 years. He has played a crucial role in the company, from marketing to helpdesk, and ensures that the IT requirements of over 300 clients are continuously met. With his innate passion for technology and troubleshooting and a particular interest in Apple products, Jack now delivers the most comprehensive tech guides to make your life easier. You can connect with Jack on LinkedIn.

Recent Posts