Elastic SIP Trunk Tutorial for Call Center Management
November 17, 2022 / 0 comments

By Dean Garfinkel, Founder and Director


What is an elastic SIP trunk (sometimes referred to as elastic SIP trunking or unlimited SIP Trunk)? And why should your call center operation use an elastic SIP trunk?

I realize this is a somewhat basic blog post for many readers, but there are many call center leaders that are exploring new telecom services because their current provider is struggling with calls getting blocked or mislabeled. This blog post is designed for someone that is new to the term "elastic SIP trunk."

Before I explain what an elastic SIP trunk is, I'll first give a little background. First, we had a voice circuit delivered to a company's phone hardware in T1 or PRI format. Then, with the invention of VoIP, SIP trunks became the standard. Now, everyone wants an Elastic SIP trunk.

SIP trunks, which utilize SIP protocol, replaced the old analog voice circuits, delivered in T1 or PRI format, and is now the de facto telecom standard protocol. A SIP Trunk is an IP-to-IP connection, unlike its predecessor, called TDM (Time Division Multiplexing), which was basically a wire using analog signaling, physically run from point A (the telecom company's central office) to point B (your office). Today, SIP trunks co-exist and interop with these legacy networks as it will be for a few more years before the legacy networks are upgraded.


What is an elastic SIP trunk?

SIP trunks are set up to allow a fixed number of concurrent calls or "trunks." Whereas Elastic SIP trunks automatically scale the number of concurrent calls it can carry up or down, eliminating outbound/inbound call congestion or busy signals that can adversely impact your sales team.

Without Elastic SIP trunks, dialer or network admins need to regularly run traffic studies to ensure each SIP trunk is sized appropriately and ready to handle call surges during your business's busy season.


An elastic SIP trunk is easier to manage vs traditional sip trunks


Advanced features of an Elastic SIP trunk

Your teams realize several major benefits with an elastic SIP trunk (also sometimes referred to as Elastic SIP Tunking). It's the same thing, but the correct name is elastic SIP trunk.

The SIP standard which is voice over IP is versatile, providing a lot more information on every call. In fact, the meta data of a SIP call lives cradle to grave. That means everything about that call, from the first type of device that initiated the call, the dialed number, the calling party, the CNAM (caller name display), to every carrier and piece of their switch equipment in the middle of the call to the called party answering the call is contained in this meta data.

Advanced networks can use this information to help route calls to maximize contact rates. Telephone carriers who can recognize various reason codes, which are indicators as to why a call may not be accepted by a called party carrier, can re-route or retry a call over alternate SIP trunks.

SIP allows for additional data to traverse with a call. For example, SHAKEN/STIR (designed to stop fraud calls), is meta data which is used to authenticate a call. The goal of SHAKEN is to ensure every call carries an Attestation that is inserted by the originating carrier. This Attestation is in the form of a Token. The Token tells the ecosystem the name of the telephone carrier that originated the call and includes a level of Attestation of A, B, or C. A means the carrier knows its customer and that the customer is authorized to use the calling number being presented. A government agency can use the token to immediately trace the source of any call.

Another use case is sending meta data in the call like the "reason for call," your company name, and your company logo. We call this Rich Call Data.


Benefits your call center sees from an Elastic SIP trunk

Reduced costs represent the greatest benefit you will see from an elastic SIP trunk. You pay a flat rate for traditional SIP trunks, no matter the call volume, time of day, or even if your call center takes a day off due to a banking or government holiday. An Elastic SIP trunk follows a fee schedule that only charges for what you use.

An elastic SIP trunk is easier to manage and lets your IT staff manage real-time call capacity. During periods with high call volumes and elevated traffic, your capacity increases, reducing rejected calls, lowering customer frustration, and improving customer satisfaction. The system can also make better decisions when re-routing calls to remote customer service reps working from a home office, which can lower incoming call wait times.


The cost of an Elastic SIP trunk vs traditional SIP trunks

Your call centers can lower costs on several fronts:

  • Unlimited call capacity is based on what you use, rather than limits based on a plan. This works perfectly if you have seasonal peaks or times of high traffic volume that you don't expect (like during an emergency or disaster when people call your company).
  • Connection requirements are standard and IP-to-IP. The cloud-based structure works with the software you already have in place.
  • Real-time call monitoring and analytics, call recording, and bring your own carrier (BYOC) are also possible with an elastic SIP trunk.


How QVD helps your call center with an Elastic SIP trunk

Quality Voice & Data is a SIP provider that provides an Elastic SIP Trunk for your call center. We have packages that include features that increase contact rates, that make your company run more efficiently and effectively, giving you the tools you need to be successful.

  • When a QVD customer calls an AT&T, Verizon, or T-Mobile wireless device, their calls arrive with a check mark, the symbol for VERIFIED.
  • When a QVD customer calls a Google phone or Android device, their phone number, logo, and the reason for calling is displayed.
  • QVD SIP Trunk reporting will show you how your SIP trunks are performing, how your caller IDs are performing, and together with our analysts we can make changes necessary to further enhance your contact rates.
  • Utilizing our SIP Trunks, our customers can take advantage of our Trusted Call Completion® suite of services.


Talk to an expert about how an Elastic SIP Trunk can help your business today.


Dean Garfinkel is the President of Quality Voice & Data, an Authorized Shaken Service Providerenhanced telecom solutions provider to the telemarketing and call center industry. Dean’s passion for creating value-added solutions for his clients has resulted in numerous solutions which are industry-standard and used by most Fortune 500 call centers and their call center vendor partners. Dean can be reached at dean@qualityvoicedata.com or 516.656.5115.