What is SIP Trunking?

SIP trunking is a method by which business phone systems can operate using an Internet connection instead of a traditional phone line.

SIP Trunking:

Costs Less

Costs Less

Scalability

Scales Easier

Reliable

Offers More Reliability

SIP trunking is provided by SIP providers, which are similar to traditional phone companies, except SIP providers give access to phone lines over the Internet (and SIP service is significantly less expensive – sometimes as much as 60-80% less).

How Does SIP Trunking Work?

SIP trunking works with VoIP phone systems (Voice Over Internet Protocol) and is based on SIP (Session Initiation Protocol).

Sangoma Sip Trunking

SIP, which is the basis of SIP trunking, is the standard communications protocol for voice and video in a Unified Communications (UC) solution across a data network.

SIP trunking eliminates the physical connection to a phone company. There are no hardware, wiring, or circuit boxes to maintain for connection to the PSTN.

A SIP “trunk” is installed virtually over your business’s existing Internet connection, therefore replacing the need for traditional analog phone lines.

Reducing multiple phone lines into a single point of entry drastically reduce charges for incoming lines and the IT cost associated with the maintenance of those lines. (Some organizations prefer to maintain standard lines for faxes and alarms.)

SIP Trunking with Your Phone System

Many companies already use VoIP within their phone system on the Local Area Network (LAN) to connect to IP phones.

SIP trunking also uses VoIP to take advantage of shared lines, such as a company’s Internet connection, to allow more flexibility in communications.

Traditional phone systems (that aren’t already VoIP-capable) can be connected using common VoIP gateways to take advantage of SIP trunking and reap the significant cost benefits.

Direct Inward Dialing Number (DID)

A phone number, or Direct Inward Dialing number (DID), is less expensive when purchased with a SIP trunk.

Traditionally, when a DID is obtained from a phone company, charges are applied for the DID, IT and maintenance services, and the hardware connecting the shared physical lines or channels. A DID provided without these infrastructure costs is more affordable.

Benefits of SIP Trunking

Cost Savings

The cost savings and communications benefits of SIP trunking are substantial. If your business is experiencing any of the following, SIP trunking can likely help in a big way:

  • High monthly phone bills
  • Costly charges for incoming phone lines
  • Long distance charges
  • IT and maintenance fees
  • Constraints of limited communications technology

SIP trunking allows companies to only pay for the number of lines they need as opposed to getting locked into excess analog lines or partially-used T1s and PRIs. This allows companies to make more efficient use of communications costs and reduce or eradicate wasted resources.

Scalability

Scalability

Because SIP trunking uses a virtual connection, adding lines or modifying service is fast and simple.

Reliable

Reliability

SIP trunking with VoIP increases reliability of services by providing a level of redundancy. When system failures and emergencies occur, SIP trunking providers can reroute services to a redundant data line or forward the PBX to mobile phones to keep your business up and running.

Other Benefits

  • Works with most modern phones
  • Ability to transfer and use your old phone numbers
  • Affordable phone numbers for all your team members
  • Less maintenance – No longer have to maintain analog and IP infrastructure

SIP Trunking vs. PRI

If you’ve been shopping around for business phone systems, you’ve probably come across the term Primary Rate Interface (PRI). You’ll often hear people compare PRI to SIP trunking, and it’s important to know the pros and cons of each before making a decision. 

PRI and SIP trunking are two different ways to “connect” your phone system to the outside world. On the most basic level, SIP trunking uses your Internet connection to make phone calls, while PRI uses a dedicated physical connection.

PRI

Uses Traditional Phone lines

SIP Trunking

Uses existing Internet connection
Pros:
  • Quality of Service is guaranteed
  • Works with older phones that aren’t compatible with VoIP


Cons:
  • Typically more expensive than SIP
  • Connections are physical and new lines have to be installed when your company grows
  • Requires in-house IT staff to maintain
Pros:
  • Usually more cost-effective for businesses
  • Scales quickly and service can easily be modified
  • Connections are virtual, so no physical lines


Cons:
  • Quality of Service is not guaranteed, as Internet
    connections can introduce lag and delay if not configured correctly or there is insufficient bandwidth
  • Does not work natively with older analog or digital
    phones

SIP Trunking vs. VoIP

SIP is a protocol that helps enable VoIP phone systems. So, while the two terms can seem like different services, they actually work to accomplish the same goal – to run your business phone system over your Internet connection and internal data network. Check out our VoIP Basics page to learn more about how VoIP works and how it can benefit your business.

Questions to Ask When Switching to SIP Trunking

To prepare your company for SIP trunking, you first need to consider a few questions.


How many people are on the phone at the same time during your busiest hours?

That will determine how many channels you will need. SIP trunks allow for quick and easy scaling, so you may add or remove channels as needed if you under or overestimate.

Will your call volume remain fairly consistent from week to week, or will it fluctuate?

With SIP trunking, you can purchase channels. When call volume increases, Concurrency Bursting allows you to burst beyond the number of channels you have. This is explained more on our SIP trunking pricing page.

Will you need to scale or add new users relatively quickly?

This is an important factor, particularly when deciding between on-premise and hosted phone systems. Click here to learn more about hosted vs. on-premise options.

Is Your Nework Ready for SIP Trunking?

Network considerations that must be examined include total available bandwidth, Quality of Service, and firewalls. Upgrading your Internet connection may be necessary to ensure sufficient bandwidth to carry a new phone system on top of typical Internet usage for your company.

Quality of Service (QoS):
Equally important to bandwidth is Quality of Service. QoS prioritizes your voice traffic and ensures that your phone calls are going to get the bandwidth needed, regardless of what else is happening on the network. The vast majority of business grade network routers will provide QoS for your network.

Firewall:
A firewall is critical to maintain security both within a LAN and Wide Area Network (WAN). Though firewalls are a critical component to any business network, they must be configured correctly to work well with SIP trunking.

E911:
For safety, it is essential to add Enhanced 911 (E911). E911 is a feature of the 911 emergency-calling systems that places VoIP emergency callers with the appropriate resources by associating a physical address with the calling party’s telephone number.

Network Bandwidth Equation

Use the following simple equation to determine the necessary bandwidth to support your calls:

(number of concurrent calls at your company’s peak)

x

100 kilobits per second

=

bandwidth in Megabits per second (Mbps) needed for calls

 

SIP Trunking Pricing

SIP trunking pricing varies depending on how many channels you need. Per channel pricing, also known as “channelized”, is great for businesses that prefer a set, predictable monthly phone bill.

To see how much SIP trunking costs, check out our SIP trunking pricing page.

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