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11/12/2023 - Jodie Penk

What is SIP Trunking?

SIP (Session Initiation Protocol) Trunking is a digital way of making and receiving phone calls and other communications over an internet connection. The term trunking refers to the method of consolidating multiple communication channels into one singular connection. SIP Trunks provision VoIP (Voice over Internet Protocol) connectivity between on-premise phone systems to the PSTN, this allows for the efficient use of resources and connection to the telephone network.

How SIP Trunks work?

SIP Trunks work as a connection between your business phone system and the Internet Telephony Provider (ITSP). This works by using the SIP Trunk to route communications over data networks via a SIP-compatible PBX (Private Branch Exchange). This process may sound complicated however, this will all be handled and managed by your chosen provider. 

Who needs a SIP Trunk Network?

In short, any business who needs to make regular communications (outbound and inbound) needs SIP Trunking! With the ISDN switch-off fast approaching, SIP Trunks are an essential component to ensure that your business communications remain unaffected during the transition.

Sip Trunking for businesses

Small Medium Sized Businesses

SIP is perfect for small to medium sized businesses due to it’s cost effectiveness and its scalability. If your business should expand, it is incredibly easy to increase your systems capabilities all while still remaining affordable.

Large Enterprises

Having a reliable unified communications platform is essential for any large business. Not only do SIP Trunks allow you to consolidate all communication channels into one system, but they can also help with improving productivity and customer experience. Due to the scalability and flexibility of SIP communication, it has never been simpler (or cheaper!) to effectively manage your business communications.

Companies with Multiple Locations

With post-COVID business practices being more popular than ever, we have seen a significant increase in remote working with businesses operating across multiple global locations. By implementing SIP into these businesses internal and external communications are simple and cost effective no matter where they are going in the world! By utilising a provider with a global SIP network, like Fuse 2, gone are the days of paying expensive rates to route voice traffic in and out of different countries.

Businesses with Fluctuating Call Volumes

One of the main benefits of implementing SIP Trunking into your business communications is the ‘pay-as-you-grow’ structure. This means that you can start off with as little SIP Trunks as you need and if the time comes where you need more, you can simply call up your provider, provision more SIP Trunks and away you go! This is a great, cost-effective way to expand your communications as you are only paying for the channels that your business really need. 

Businesses Seeking Disaster Recovery Solutions

All SIP Trunks are configured to automatically failover during any event of an outage. By partnering with a company such as Fuse 2, your communications are in safe hands no matter the situation. If there is an outage at a certain data centre, the technology kicks in to seamlessly failover to another data centre. This results into little to now downtime for the end customer. 

SIP Trunk Example

We operate on a fully independent global SIP network. This means that we can route calls all across the world via SIP Trunking, with the guarantee of lower latency and higher call quality. SIP Trunking via an independent network allows for many enhanced feature-sets such as number porting which is a popular option for many of our customers. This allows a business to keep their old numbers, despite the switch of systems.

Role of SIP in voice over IP (VoIP)

SIP Trunks in short, are the backbone of VoIP! SIP in VoIP works by filtering through the incoming communications and defining the messages sent between different endpoints. SIP is the technology that supports VoIP in an application protocol by carrying all forms of digital media (including SMS, voice and video) over the internet. 

Why use a SIP Trunk?

SIP trunks benefit many businesses from cost savings, scalability, flexibility, geographic flexibility, reliability, integration with unified communications, advanced features, quick deployment, and centralised management of their communication infrastructure with SIP Trunking.

  • Low Installation / Setup Costs
  • Easy to Scale
  • Cost Effective 
  • Easy to increase your investment in your existing infrastructure / PBX

Considerations with SIP Trunks

Choosing how many SIP Trunks you need for your business is essential in keeping your business communications up and running. If you underestimate the amount of SIP Trunks / Channels / Minutes you need, this could cost your business in many ways. Although it may sound cliche…it is always easier to decrease the amount of trunks you need rather than increase them!

How many concurrent calls do you use?

Figuring out the amount of concurrent calls you use is one of the main factors you need to consider when switching to SIP. A concurrent call basically means, how many people will be on the phone making/receiving a call at one time within your business. If you happen to miscalculate your concurrent calls, once the threshold is met your business will not be able to make nor receive any calls.

How many new numbers will you need?

When upgrading to a SIP system, you will need to assess how many new phone numbers you will need. This is great for businesses who work internationally and need phone numbers all to be hosted in the same network for latency and cost reasons. The ability to purchase new numbers from anywhere in the world is great for businesses who, for example, have different customer service representatives in multiple countries.

Are you porting any existing numbers over?

If you would like to keep your existing numbers, this is just as simple as purchasing new numbers. For example, if your business has used the same phone numbers for many years it may be detrimental to change this number. Porting (the process of moving one network to another) can take roughly around two weeks and is a stress free process for the end user.

Security concerns

The security of your SIP Trunks is all down to your SIP providers network. At Fuse 2, we operate on a fully independent SIP network – this means that we have full access to the network and can see all incoming and outgoing phone calls. Our network has been built with reliability and security in-mind, which is regulated and scanned regularly. Encryption is a key part of any network and having technology such as spend limits and DDoS mitigation strategies in place means that the risk of unauthorised access to your phone system is very low.

Integration with existing systems

SIP Trunks are the backbone of all VoIP solutions and as great as they are, you can’t use them on their own. This is why they are compatible with many popular third party platforms – such as 3CX and Microsoft Teams. SIP Trunks are the technology which can turn such platforms into fully functioning phone systems.

As the world becomes more digital the future of SIP Trunking is forever expanding. With the ISDN switch-off fast approaching, the switch to VoIP and SIP is inevitable meaning eventually, all communications will be conducted over the internet. With the switch happening in 2025, it is crucial for businesses to evaluate their communications now. This will eliminate the possibilities of providers taking advantage of the late switchers closer to the time and significantly upping the price of a new system!

Read ISDN alternatives

Conclusion of SIP Trunking

In conclusion, if your business wishes to remain afloat in the ever changing world of communications, now is the time to research how SIP can enhance, simplify and future proof your communications. Should you wish to find a solution that is right for you and your business, get in touch with one of our SIP experts today to find a bespoke package that ticks all of your requirements!

SIP Trunking FAQs

If i have SIP Channels do i need to switch to SIP Trunks?

A SIP Channel is the capacity to support outgoing and incoming calls to a network. Every SIP Trunk contains a number of channels, which are simply virtual versions of telephone lines. You can determine how many channels you need depending on the amount of concurrent calls your business makes and receives.

What are the benefits of SIP trunking?

Low Installation / Setup Costs
Easy to Scale
Cost Effective 
Easy to increase your investment in your existing infrastructure / PBX

What are SIP used for?

SIP (Session Initiation Protocol) Trunking is a digital way of making and receiving phone calls and other communications over an internet connection. The term trunking refers to the method of consolidating multiple communication channels into one singular connection.

What requirements do I need for a SIP Trunk?

The basic requirements you need to implement SIP Trunking into your business is simply an internet connection with a good bandwidth and speed. You will also need an IP PBX (The central component of most modern VoIP phone systems) that is compatible with the SIP protocol required.

Is there a limit on phone numbers for SIP Trunks?

In short, no there are no limits however, do take this with a pinch of salt! You can add a thousand numbers to a trunk however, if your concurrent call / minute allowance do not accommodate for these numbers your business will not be able to make or receive calls.

Fuse 2 are now the official range holder of all iHub numbers. If you have any information regarding legacy iHub services please get in touch +44 330 088 0333