Make An Enquiry

Please use the form below to contact us directly, if you wish to make a reseller enquiry then please visit our reseller enquiry page.







What is SIP Trunking?

Session Initiation Protocol diagram

SIP Trunking is a service that allows you to connect via Session Initiation Protocol to an Internet Telephony Service Provider’s network. In simple terms, this means that you can use this service to send and receive phone calls across the internet.

The trunk or connection to the provider’s network can be tailored to your specific needs.

It can have a limit on the number of calls that can be made at the same time. This is generally known as channel usage and this forms the basis of how the service is billed. Each channel is charged at a cost per month. What differs from traditional telephony is the ability to increase and decrease this without having the penalty of always paying for the highest amount. The service can be set up to allow for national calls only, or for national and international together, in fact, you can choose to either allow or disallow calls to any worldwide destination.

Benefits of SIP over traditional
fixed line and digital services

Reduced costs

Reduced costs

By utilising your existing PBX or IP infrastructure and purchasing the small amount of equipment required, companies can save over 40% on their legacy business telephony system.

Reduced time to deliver

Reduced time to deliver

SIP trunks can be created on the day and can be deployed by the client in a very short timescale, as opposed to traditional analogue and digital solutions, which can take anything from seven days to multiple months.

Choose your numbers

Choose your numbers

Remove the restriction of being tied to your local exchange area and the numbers that are provided within that area. You can have numbers from London, Birmingham or Manchester all sent to your office located anywhere in the country.

Choose your PBX

Choose your own IP PBX

Choose your own IP PBX. Our service is proven to work on most popular IP PBX models via our simple registration method.

No Compromises

No extension costs

Pay for how many concurrent calls your business requires, not how many extensions.

Trusted by companies throughout the UK

Latest SIP Trunking Blogs

SIP Trunking FAQ

What is the platform ability of SIP trunking?

Thanks to SIP being a standardised technology, compatible PBXs are not hard to come by. If a PBX, or phone, or hosted system, is SIP compatible, then you should be able to use a provider’s SIP trunking service.

What are benefits of VoIP Calls with SIP Trunking?

A benefit of VoIP calls with SIP Trunking is that since the user has their own PBX system, they will be able to control exactly what happens with their own VoIP calls. Whilst there won’t be many benefits to the call quality, there will be routing benefits which will ultimately allow your business to operate more efficiently.

Advantages of SIP trunking?

One of the many benefits of SIP trunks is that businesses typically save over 40% in costs when they adopt SIP trunks into their phone system. Saving is mainly due to the fact that SIP trunks can work with pre-existing IP-PBX systems, meaning that you may only need to purchase the odd piece of equipment here and there.

The ability to be flexible is of utmost importance in a business and with SIP trunks, you’ll get just that. If your business has increased the number of its employees or is experiencing a surge in calls, then you can instantly add channels to your system with the click of a button.

Unlike traditional phone systems, SIP trunks can be delivered and deployed quickly. SIP trunks can be created and deployed on the same day, a stark contrast to traditional phone systems which can very well take a week to months to function properly.

What are reasonable prices for SIP trunking?

Pricing varies. For example, here at Packnet, we charge less for a SIP trunk channel than extension because of two things. One, a customer is using their own PBX, therefore not taking advantage of extension level features. Second, the customer will be doing most of the work, which ultimately means that they’ll be using less resources.

What is a list of market niches that need SIP trunking?

Here’s a list of common ones:

  • Training facilities
  • Hospitals
  • Call centers
  • Schools
  • Enterprise companies
  • Resorts and hotels

When is it best to use SIP trunks?

Perfect for any large business with employees who need their own lines. SIP trunking is also preferable if as a company, you prefer to have all your phone systems in one place for security and management reasons as well as having the added benefit of no extension costs.

Is SIP Trunking more reliable than PSTN Telephone network?

The answer is yes.

SIP trunks work by sending calls over data, therefore connectivity is all the more important. If your internet bandwidth is not all up to par, then you may not experience A-star worthy call quality. So before you jump headfirst, make sure that you have an estimate of how many calls may be going through the business.

One of the important things you need to consider is, does your SIP provider have a redundant network? If they do, this means that calls are able to route around in case of hazardous weather and technical failures. This will make SIP trunks all the more reliable.

In addition to that, make sure your SIP trunk provider can provide your organisation with redundant server hardware. This hardware will ensure that if the hardware on one piece of equipment fails, others will not be affected.

Should I separate my voice and data network?

Yes, wherever possible. Benefits are, it’s a logical separation, you gain more control over the bandwidth used by devices, computers don’t impact voice services.

Can I replace my ISDN lines with SIP Trunking?

Of course. When you have made the decision to switch, it is important to plan and consider what changes switching over from ISDN to SIP trunking could make.

Is SIP Trunking as good as traditional
communications services?

When set up correctly voice quality is as good as, or better, than traditional communications. A well managed local network is recommended, as well as an internet connection with enough bandwidth to ensure the service can operate in the best manner possible.

The cost of calls using VoIP is generally cheaper than those made using traditional telephony services. SIP trunking differs from fully hosted in that an on-site IP PBX is normally required. However, forget waiting over 48 hours for your service fault resolution, in the rare occurrence of a fault, most issues can be diagnosed and resolved on the same day.

Connectivity is king, Packnet offers a wide range of connectivity products from Leased Lines to FTTC.