SIP trunking benefits and best practices

Get the most from your enterprise voice calling with these best practices.
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If you’ve spent any amount of time exploring business communications, you’ve probably heard the phrase ‘SIP trunking’ or ‘SIP trunk’–it’s a pretty common component in the rapidly expanding telecommunications world.

In fact, more than 80% of large businesses say that SIP is important to their business a few years ago. Imagine where that’s at now.

The advantages are irresistible. But what exactly are they, and what best practices should I have in mind?

First, a quick overview of the tech at play.

SIP vs. VoIP: What’s the difference?

First, let’s start with another acronym: VoIP.

This stands for Voice over Internet Protocol, and is the name for a variety of technologies used to deliver voice calls over data networks, such as the public internet or VPNs, instead of the traditional circuit-switched networks used for telecommunications.

As businesses scale up in size, most will use VoIP systems to route calls internally across their data network using a private-branch exchange (PBX).

This lets them reduce overheads by removing the need to manage separate data and voice networks.

SIP (Session Initiation Protocol) is a signaling protocol used for the real-time delivery of voice and media.

With the right infrastructure and interconnections in place, SIP calls can be transmitted between data networks and the public switched telephone network (PSTN), the global mass of traditional telephone networks operated by national, regional and mobile carriers.

So in very simple terms, SIP can be used to enable your on-premise phone systems to make and receive calls via data connections.

A virtual phone number, called a DID, can be assigned to your SIP connection so that customers have a phone number to ring when they wish to speak to you.

What are trunks?

As for the trunks, they’re nothing to do with swimwear. Think of them as phone lines in the old parlance, carrying the voice and media content between two endpoints, which could be VoIP terminals or phones.

The beauty of SIP trunks is that you can have as many channels as you want to point to a single virtual phone number.

This is one of the reasons why they offer significant cost savings compared to traditional telecoms.

There’s also no need to invest in expensive onsite infrastructure before using SIP.

Integrating your telephony services into your data network and dynamically managing it in the cloud leads to huge ROI savings on existing infrastructure as well, providing variable options to drive cost savings.

What about the other advantages we mentioned earlier?

4 benefits of SIP trunking

Unlimited call capacity

SIP trunking allows for unlimited simultaneous call capacity – meaning that you can enjoy as many concurrent calls to and from a single number as you wish!

This is especially beneficial for customer contact centers that receive dozens, or even hundreds, of calls a day to a centralized phone number.

Local presence

Because the phone numbers associated with SIP are virtual, they do not need to be tied to your physical location, except in cases where local regulations require this.

This means you can use DID numbers and SIP trunks for a two-way voice service that lets you conduct business from your office in Penetanguishene, even though you don’t actually have an office in Penetanguishene and you’re not exactly sure you could pick it out on a map if you had to (hint: it’s in Canada).

If your SIP service provider’s network is fully interconnected with the national telecoms infrastructure in a given country, you will even be able to make domestic calls that are routed in-country, meaning carrier-grade latency, call quality, and privacy.

You will have access to the entire national dialing plan in that country, including special numbers that can’t be reached by international calling services.

They’ll also show up as coming from true local numbers in caller ID, instead of presenting with the international dialing prefix. This is a big deal because local calls are 4x more likely to be answered than international ones.

Centralized comms

If you have multiple business locations, SIP trunking eliminates the need for individual telephone lines at each location, consolidating all branches or offices and creating a single, centralized platform.

This results in reduced hardware needs and impressive long-term cost savings. Remember though, that to fully replicate the functionality of the PSTN for business purposes, you’ll need a SIP provider that offers:

  • Inbound voice
  • Outbound voice (domestic and international)
  • Number portability
  • Access to local emergency services numbers
  • Consolidation of providers

With traditional telephone carriers, you only ever receive coverage in one country, (a handful, if you are lucky) meaning that you need to enter into contracts with dozens of service providers for a global communications footprint.

This can be a migraine-inducing process because of the local regulatory requirements of each country and the lack of consistent processes across borders.

A SIP trunk provider will take care of these headaches for you, by interconnecting with national networks in each and every country to provide streamlined services around the world.

All that’s left for you is to pick a US toll-free number here, a Chinese mobile number there, and whatever else you need.


SIP trunks are extremely flexible, allowing you to scale your communications system on-demand as your business grows.

You can easily deploy voice services and additional capacity as and when you need it, in offices around the world, without ever having to invest in costly infrastructure.

SIP trunking best practices

After all that I’m sure you’re dying to get up and running right?

Well, it’s a super quick and simple process as it happens, but there are still some best practices that you’re going to want to have in place before you make the jump.

Step 1: Check your PBX

It might seem obvious to some but there are still some legacy PBXs that aren’t SIP enabled and so won’t be able to support your new-found SIP trunk solution.

Take a quick look and see if it has an ethernet port, if it does, you’re good to go.

If it turns out it’s not compatible with SIP, you can still use SIP trunking but you’ll have to use an adapter to do so (not ideal).

Step 2: Check your bandwidth

Another seemingly obvious one on the surface, but as you’re going to be moving your voice data as well as your usual internet data over the same connection, you’re going to want to make sure you have the capacity.

That means checking your bandwidth. If your bandwidth is pretty limited you might want to consider getting a better connection before adopting SIP trunking.

Step 3: Check your settings

This is a bit of manual work you might want to take up before trying out SIP trunks. Don’t worry, it’s not too technical, and you shouldn’t need to move from your desk to get it done.

Basically, your router has this setting called Quality of Service (QoS). Turning this on means that your router will prioritize your voice traffic rather than your regular internet data.

What this will do is reduce latency on your calls and should help prevent your calls from cutting out unexpectedly.

If you happen to have a pretty old setup, you’re going to want to change your router out for one that has this setting. That way you’ll make sure your calls go as smoothly as possible.

Step 4: Decide on the number of channels you need

If you do one thing before contacting a supplier, this is it.

Most SIP trunk suppliers use the number of channels you need to estimate the price. Without it, there’s no way of comparing prices to find the best deal.

Keep in mind that, even though the price of your channels are a baseline for considering who you’re going to go with, different suppliers provide different levels of support, coverage, and compliance that might not seem obvious on the surface.