SIP Trunking Benefits: What Features Does My Business Need

This is our 2nd of 12 blogs on the subject of SIP Trunks. Subscribe in the box to the right to receive an email notification for each one in the series.

Considering SIP Trunking for your business? Take a peek at some of the top benefits of SIP Trunking that Bay Area businesses enjoy and see if it matches up with your needs!

Cost Efficiency of SIP Trunking

SIP Trunks are far more cost effective than traditional circuits. A typical business could save 50% or much more on their monthly communications bill.

Minutes No Longer Matter with SIP Trunking

Most SIP Trunk providers offer unlimited inbound and outbound phone calls.

Sizing Increments

Traditional PRI circuits have 23 voice channels. SIP Trunking comes in increments of one channel. You pay only for what you need.

SIP Trunking Eliminates Hardware

Most SIP Trunking implementations do away with traditional line cards. This lowers costs and eliminates future hardware failures.

Geographic Resilience

Traditional telephone lines (PRI and analog) are directly connected to a single Central Office location near your office. A major physical disaster such as a fire or earthquake can wipe out your communications. SIP Trunks are typically designed so the service is redundant at two separate locations to avoid catastrophic failures.

SIP Trunking Disaster Recovery

If your PBX fails, you have a major power outage or building damage, or your connection to the Central Office goes down, your SIP Trunks will still work. You can simply re-route calls to any telephone number in the world.

Choose Phone Numbers from Anywhere

Numbers can be provided from almost any location in North America. This permits enterprises to establish a “virtual” presence with incoming calls ringing at a centralized facility.

Caller ID

Caller ID is a standard feature.


DID is a standard feature.

Caller Name ID

Caller Name ID is an optional feature.


SIP trunking supports voice and video traffic.

Adding & Removing Capacity

You can add or remove a SIP Trunk in one business day and usually less. Traditional phone companies take weeks to make these changes.

Geographic Location Independence 

The traditional voice is attached to a physical location, but the flexibility of SIP Trunking allows call routing to any IP address worldwide, including home offices and softphones.

If you’re going to switch to SIP Trunking, you need to determine how many trunks (call paths) you’ll need to support your calling needs.  Remember that one Trunk supports one phone call to the outside world.

Calculating Your SIP Trunking Needs

When trying to size a SIP Trunking solution, many vendors just use an old rule of thumb: one Trunk for every three employees.

Another simple method is to duplicate the number of Trunks that you are presently using.

Using either of those methods can lead you to the wrong answer.  Since PRI circuits come in increments of 23, duplicating that number of SIP Trunks is just perpetuating your present configuration, with no consideration as to your true needs.  And using the “one trunk per three employees” ratio is using a business average as your basis for calculations, rather than a well-reasoned decision that’s right for your organization.

Fortunately, determining the proper quantity of SIP Trunks for your business is a pretty straightforward process.   First, if you have a receptionist, that person will have a very good idea of the maximum number of simultaneous calls your company experiences in the course of business. If you have a relatively small office, you can also ask the employees how many of them are on the phone at once. 

A fact to consider is that most businesses are experiencing less phone calls than in the past, as employees and customers are communicating more on email and mobile phones. You need to ask yourself if that is the case for your business. If so, you are probably currently over-trunked.

Once you feel comfortable that you know the number of simultaneous calls at your peak times, you’ll have a good baseline number.  Now, just to be safe, increase it by 20% to provide a buffer. Remember, you are saving money by converting to SIP Trunking, so the extra trunk costs won’t kill you and you sure don’t want busy signals.

In my next blog in this SIP Trunking series, we discuss Data Circuit considerations. You’ll definitely want to read this!

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