What is SIP Trunking?
SIP Trunking (Session Initiation Protocol) is the virtual equivalent of a traditional business phone line – a SIP trunk is a virtual connection to the Public Switched Telephone Network (PSTN), utilizing your internet connection. The term “trunking” itself dates back to the original days of telephone service. A trunk was a shared communication path for a large number of telephone users. SIP itself is one of the specific protocols that enable VoIP services to work. While traditional phones use physical lines and circuits to connect to the PSTN, a SIP trunk replaces the physical connections with virtual connections over your existing IP networks. Because information is transmitted through the internet and not landline telephone lines, SIP integrates voice, video data and internet services into one single line.
With the invention of VoIP and PBX, voice communications were no longer restricted to traditional circuits and landline phones. Instead through SIP, a signaling language designed to carry data like voice, video and instant messaging, we can utilize the internet to highly cut down on the cost and rigidity of older phone systems.
All SIP calls are local calls and you won’t even need a phone line. SIP Services are offered by most business VoIP providers for both small and large application, and offer a cost effective way for small businesses to maintain the professional presence – and for large companies to maintain a local presence.
How SIP Trunking Works:
SIP trunking delivers your telephone and Unified Communications services over an existing IP network, and replaces your traditional telephone lines. Through a SIP trunk, VoIP users can make calls directly to any phone on the PSTN without telephone lines by connecting to a compatible hosted PBX system.
The only three necessary elements to operate a SIP trunk are the SIP Provider that supplies the services, a phone system that has a trunk side to enable SIP, and a border element to facilitate the connection between your enterprise network and the PSTN or an external IP carrier network. These border elements can be a firewall or switch, and are usually managed by your SIP Trunking provider. With only these three simple elements any business can vastly boost its telecommunications reach. A pre existing IP-PBX installed will only make the process even easier.
Most Common Advantages of SIP Trunking Services:
Thanks to SIP, small businesses can easily appear large and professional with a level of service often reserved for more expensive solutions or Fortune 100 companies. This also makes it easier for a large business to maintain their local presence, as all SIP calls are local calls – customers don’t have to dial a generic call center number. Of course, the benefits of SIP don’t end there.
- SIP’s inherent flexibility allows for users to add or even subtract as many phone lines as they need, without the hassle of overpaying for unused lines, or waiting for your phone company to sort it all out. Everything can be handled through dedicated web portals to tailor the phone system to your needs on the fly.
- While analog trunks can be disrupted by bad weather and rely on expensive phone companies, SIP trunking can help mitigate disaster scenarios by properly rerouting and prioritizing calls to different networks or phones.
- Consolidated hardware and setups reduce the installation and maintenance costs of adding or changing your existing phone system. The system can grow without even adding new hardware, a new trunk for extra phone lines doesn’t require any new devices.
- Take your phone number with you anywhere you travel or move offices, as your number isn’t bound by location. If your primary link to the SIP provider fails or just isn’t where you are, any internet connection can serve as a temporary link to your SIP network.
- If your business does a lot of calling oversees, SIP can offer free international calls based on your provider and pricing plans (compare industry leading SIP providers above).
How SIP Trunking Can Improve Your Business Communication
SIP trunking replaces old school styled connections that were just way more limited than IP networks. Adding phone lines required the purchase of a new trunk that included at minimum, 24 additional lines. You may only needed just one additional line, but had to purchase an entire trunk – now you spent more money and have 23 useless lines. One of SIP Trunking’s strongest points is its scalability, it will grow painless with your business, or even shrink if your needs change.
Because SIP trunking combines video, data and voice all into one single line, your local, long distance, broadband internet service, and even video calls are all handled through one network. With dynamic bandwidth allocation, you can ensure the necessary resources are available for basic web use, while maintaining a consistent call volume and quality.
Not to mention with every service on the same network, the necessary hardware you need in house drops dramatically. No longer will you need in house IT managers just to stay on top of your phone lines, with Sip technology nothing is on-site. Your provider sets up a SIP proxy server to provision incoming, outgoing and PBX calls and they even take care of all technical support to cut down on costs and headaches.
Service outages are a thing of the past with SIP trunking. If one location shuts down temporarily, SIP trunks will automatically reroute calls to any other locations and extensions to at least partially restore services. If there is an unexpected power outage, calls can be rerouted to a separate satellite office. Companies with an international presence, or even considering outsourcing, can take advantage of this benefit. The flexibility of SIP trunking allows you to spread staff across the country or even the world. More on How SIP Trunking Will Help Your Business.
Why Use SIP Trunking Over Alternative Solutions:
By sending all of your data over one single connection, it doesn’t take much to start saving money with a SIP trunk. SIP trunks alone are more than 25% cheaper than PRI trunks, and that’s before calling rates. Beyond a level of flexibility that just not available in traditional phone services, SIP even allows you to make free voice calls between any offices on the same VoIP system. With a large list of providers and hardware taken care of on their end, pricing and installation costs are much lower, and rates for calls are lower as well.
Another option, Primary Rate Interface (PRI) trunking allows for large businesses to transmit a large number of voice and data communications from multiple locations, but is mostly seen as an older, almost outdated alternative to SIP. As it relies on the use of T1 lines, telephone circuits might need to be added and calling fees are generally more expensive. More on SIP vs PRI here.
Whereas PRI trunking can fail in adverse weather, SIP services ensures you will stay connected and automatically reroutes calls as necessary. As an internet-based replacement for traditional phone service, SIP is a central part of how VoIP works and allows for a more robust, and flexible unified communications system.
Choosing the Right SIP Trunk Solution:
Once you’ve decided SIP trunking is the right method of connectivity for your business, the most important step is to then choose which SIP provider best fits your needs.
- Network - With a lot of provider’s simply rebranding SIP trunking service hosted on other provider’s networks, it’s important to distinguish if the network is hosted and run by your SIP provider directly. Everything is easier without a middleman.
- Security – A standard concern for almost any service over the internet, it’s important to ensure the necessary security measures are in place to keep your information safe. With all of your data transmitted over the Internet you would want your SIP trunk to be secured with a solid, protected network and anti-fraud system in place to monitor any feedback and mitigate any risks.
- Number Porting - If you want to keep your existing phone number, make sure your provider is capable of number porting from your specific region. Most services and providers do offer porting, but it can be limited in different regions around the world.
- Customer Service – Although SIP Trunking itself does a good job and disaster mitigation, if everything goes down you’ll want to make sure you can get ahold of your provider as soon as possible. A five minute outage could quickly turn into a massive, and costly, headache.
- Pricing - As with any service, pricing will vary based on different providers and levels of service offered. Of course, you pay for what you get and if you want business-class service you should be prepared to pay respectively. Those rebranding offers tend to be on the cheaper side, but quality might suffer.
How to Get Started with a SIP Trunking Service:
In order to properly set up a SIP trunk system, you first need to determine the resources that you will need.
- Router/firewall setup that has support for port address translations and static port mappings
- A Fully Qualified Domain Name (FQDN) with a resolution to a static external IP
- Bandwidth with the capacity to handle real time VoIP traffic (anywhere from 30-120 kb/sec)
- A provider of VoIP that is supported
After you have the appropriate setup, you can move forward into the actual installation.
Setting Up an Account with a VoIP Provider
The first step to establishing a SIP trunk is to create an account with a SIP compatible business VoIP service provider.
Conducting a Test of the Firewall
The firewall that is between your system and the VoIP provider may not be able to route traffic properly if the configuration is not properly set up. As the middleman, you must test the firewall for compatibility for the SIP port and the Audio Port range. If the check does not work out, the firewall itself must go through a troubleshoot.
Add the VoIP Account
The next step is to configure the VoIP account into your system. You should see an option to add the SIP trunk settings in your user interface. Select the options appropriate to your geographic location and the numbers that are assigned to your new trunk.
You will need to name your VoIP account. Compare the details for your server hostname and outbound proxy with the details from your VoIP provider. Set the number of simultaneous calls that are allowed by your provider. Set whether the authentication is based on your registration details or on your IP. Specify how the routing on your main number should be set up, and specify your DID numbers by adding the ones that are associated with your account. Set the number that you want to show up on your caller ID. Be sure to save your settings.
Route Your Calls Over the New Trunk by Setting Outbound Rules
You must now decide which kinds of calls will be routed over your SIP trunk. Create the outbound rules based on your needs and the capacity of your infrastructure. Keep in mind that you can route calls through different trunks - SIP trunks or gateways. You can base these rules on the group or individual that is making the call, the length of the number or the number that person is dialing.
Make sure that the names for the rules that you set up are intuitive enough to translate between departments. Specify the rules that will trigger each rule. For instance, you can create rules only for numbers that have a certain prefix, calls that come from a certain range of extensions, calls that go to numbers with a certain length or calls from a specialized extension group.
You will also need to specify how these outbound calls will be routed. Each new gateway and your SIP trunk will be listed in the route dialog. You may also be able to set alternative outbound rules that will step in when the first set of routes is not available. You may also transform the number that is set up to match with the outbound rule by stripping the digits and using the prepend option for each of the routes.
Setting up SIP trunking can create a much simpler communications structure within your organization and future proof your infrastructure for expansion into real time enhancements. You may also experience a huge cost savings. Follow the tips above to ensure the viability of your new system, and be sure to test it periodically to maintain its day one veracity.