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SIP Trunking FAQs

A Blog for ‘Frequently Asked Questions About SIP Trunking’ by SIP Specialist Susan!

Susan Thorogood

Hi everyone, my name is Susan Thorogood. Also known as one of the ‘Super SIP Specialists!’ I’ve earned that nickname here at ClearlyIP by being one of the go-to people for SIP questions for business telecom.

I have been learning so much and fielding questions from customers and partners about our SIP Trunk services, so I thought, why not take what I have learned and help educate you on my most frequently asked questions. I thought I would write a blog and clear up some of the confusion around SIP Trunking for business. I get calls almost daily asking me about the difference between metered and unmetered, trunks, channels and porting costs, and processes. Some people don’t know what exactly SIP Trunking is, and that’s what I’m here for.

I wanted to write a clear explanation that all our customers can read to help them along their SIP-tastic journey! This blog is also in line with some new options posted on our updated SIP Trunking webpage explaining different call path options. Check it out here:

Plus, we recently set up some automation on the back-end of our porting process for live updates to allow ports to happen faster by communicating with the losing carrier and vendors more automatically. That time saving gives us a serious competitive edge. It can shave days off our porting process since updates are real-time. A typical SIP carrier takes 10-14 days to port numbers. At ClearlyIP, we are closer to 5-7 days with the ability to submit faster to our upstream carriers. Have I lost you already? Don’t worry, I’ll clarify in just a bit.

My goal is to help you better understand what SIP is and how it can help your business. SIP is a buzzword that’s been trending for the last three years. Still, it is getting increasingly more popular as businesses move to VOIP. So let’s start solving SIP!

SIP Trunking 101

SIP stands for Session Initiation Protocol. SIP trunking works with an IP-enabled PBX (Private Branch eXchange), also known as VoIP. It’s a method of conveying voice and other unified communications services over the internet. The bottom line is this; SIP trunking replaces traditional telephone lines.

SIP trunks utilize a packet switch network; they are virtual phone lines that let users make and receive phone calls over the internet to any other phone number. SIP trunks utilize a packet switch network. Voice calls are broken down into smaller packets and sent across a network to the recipient.

Before SIP became a popular and reliable method of transmitting voice signals, the Public Switched Telephone Network (PSTN) carried all telephone calls. The PSTN is the network that has those copper phone lines we traditionally associate with the “telephone.” The PSTN is a circuit-switched network, which requires a physical connection between two points to complete a call.

Understand Locations, SIP Trunks, and SIP Channels

ClearlyIP allows you the flexibility to have multiple locations (SIP Trunk system registrations) on an account. You can manage these in our trunking store and even create CDR reports for each location. But I am getting ahead of myself. Let’s get back to understanding our verbiage and services. When you get started, you are going to create a location. This will be where your SIP channels, numbers, and additional services are going to be configured and managed. What is a SIP channel vs. a SIP Trunk? A SIP channel is equivalent to one incoming or outgoing call. A SIP trunk (or location in our Trunking store) can hold an unlimited number of channels. That means that your business only needs one SIP trunk/location, regardless of how many concurrent calls you expect. The number of channels required depends on how many calls your business will make at any one time.

I’ll give you an example here. Let’s say you are moving away from a physical phone system onsite that has a full channel PRI, and you want the same call capacity. We would recommend a single SIP Trunk with 23 Channels. A full channel, PRI/T1, typically has 23 channels/lines, which would be the equivalent. If you have a 10 OL analog overline service, it would be one SIP Trunk with 10 Channels. It’s that simple! But let me tell you, the features and cost savings will be no comparison!

Why Go SIP?

There are many benefits to utilizing SIP for your business. One of the most important is the reduced communications costs.

In many cases, unlimited local and long-distance calls to most of North America are bundled in with the monthly fee for each SIP channel. What’s more, top SIP providers like ClearlyIP allow you to provision channels on-demand. Meaning you get and pay for only the number of channels you need right now and can quickly grow at any time.

Another one of the excellent benefits is the ability to have burstable channels; these are channels that are available to the location that you just use on a “per minute rental” for when the line is in use, and otherwise, you just have your standard billing. This is flexibility at its finest to have the ability to burst and support additional calls or callers only when needed and not have these fixed costs on your monthly services.

Additional benefits include built-in business continuity features, network consolidation, and unified communication features like video, presence, application integration, and instant messaging.

Key Steps to Implement SIP Trunking: Porting Process & Network Changes

Number Porting:

Many, if not all, customers want to retain some or all of their telephone numbers as they move to SIP. Your primary business phone number is your companies identity and is key to how customers reach you. This process is called “porting.” We make this process so simple and work with you through the process to make this as painless as possible. When you turn up a new location, you must assign a number to the location. This is usually used for testing the services before porting. Once you have ported in your numbers from your current provider, you can cancel this new number or keep it. Again, ClearlyIP allows you to customize your solution to keep what you want and cancel what you do not need.

Business Phone Numbers

When porting your numbers, you need to submit all of the numbers you want to be ported to your new carrier. Since you’re paying to port each number, make sure you bring all the numbers you want to keep and not ones that the other provider has allocated to you for billing or other reasons. There is no reason to continue to pay for numbers that you do not want or need like before; with Clearly IP, you only pay for what you want and not what we want you to have.

Typical Porting Timeframe

Transitioning from your old analog or PRI to SIP Trunking is a process that can take from 10 days to two months, depending on your provider. At ClearlyIP, we pride ourselves on a standard 5-7 business day turnaround. My girl Emily oversees porting here at Team Clearly, so customers work with her to ensure smooth transitions. She has magical porting powers, but we are always at the mercy of the losing carrier, so we can only do so much to get porting completed quickly.

Moving a few numbers that are on one phone bill is relatively quick. Multiple phone bills or larger blocks of numbers will require more time. Lastly, some carriers have put up roadblocks or PINs on numbers in an attempt to avoid losing numbers, purposefully slowing the process down and trying to keep the revenue coming in for a bit longer. If you want to get ahead of the game, a PRO tip is before submitting the port order, request CSR (Customer Service Record) from the current carrier. This will provide you with all the pertinent information the losing carrier will accept for a port out. It also gives us the ability to dispute them if they reject the port for a piece of info on that CSR. Always nice to beat them at their own game and have the resources at hand to make this transition as smooth as possible. Rest assured, we work with you to travel these bumps in the road to get a successful transition.

Point-of-Sale Systems, Alarm and Fax Numbers

To rid yourself entirely of your old telephone company, you’ll need to convert Fax and POS devices to an alternative connection method, one that is preferably Internet-based. Most businesses find savings once free of their old telephone company.

Carrier Letter of Agency

In order for the numbers to be ported, you’ll need to sign a carrier letter of agency. This authorizes your new carrier to act on your behalf and place the necessary Local Number Portability (LNP) order. This is completed in your trunking store under Porting and then Submit Porting Request.

Recent Copy of Business Phone Bill

To verify, you will be asked to provide a copy of your telephone bill (one that’s less than 30 days old) to your new carrier. As per my PRO tip above, to be proactive, you may want to request a CSR from your current provider to make sure you have everything detailed to have a smooth port.

Prep Work of Existing Phone System

A gateway will need to be installed on legacy PBX’s and should be tested in advance. For an IP-based system, the requirements vary. Some require a card, others an external device called a Session Border Controller (SBC), and some only require a simple SIP Trunking license. For SIP-based PBXes such as ClearlyIP’s Business Connect or Clearly Cloud Platforms or the open-source project- FreePBX®, no additional equipment or licensing is required. We also work hard to have all the steps detailed on how to get your services all up and ready on our Wiki. You can find this on our website under Support and then WIKI and Documentation.

Potential Network/IT Infrastructure Upgrades

You or your data company may need to install a new router or firewall, set up, depending upon your configuration, Quality of Service (QoS), and define the proper routes for voice and data traffic. Your router and firewall need to be voice-friendly and reliably pass phone traffic in both directions. If you are going to change circuits, add a new dedicated to SIP Trunking circuit, or set up a redundant network, you’ll have some technical work to do to establish this new cloud-friendly, VoIP-capable network.

New Data Circuit (Optional)

According to your SIP Trunking provider’s recommendations, You may need to order a new data circuit. Lead times for data circuits range from 10 business days (DSL) to several months (fiber). Testing will be necessary after the new data circuit is delivered. Finally, your data vendor or IT person may have to make additional internal network changes.

How The Porting Process Works

The actual porting of phone numbers on the due date is a quick process. It is the preparatory work of organizing all the paperwork, the phone numbers to be ported, and the copies of phone bills that take the most time. Once organized, you can submit the port to the new carrier. Once submitted, the porting of the numbers is all done in the background between the Losing Carrier and the new SIP Trunking provider.

Cancellation of Old Services

Most companies don’t port all of their numbers over, opting for new numbers from the new provider. Some circuits will be automatically disconnected while porting numbers to the new carrier. Ensure you contact your old phone company immediately after the port to confirm that they have or will disconnect all unused circuits. Just remember to check out your current account status to see your cancellation terms, so you are informed going in.



Critical Pointers for Choosing The Right SIP Trunk Provider

Since SIP trunking is an active market, you may find several players in the industry. How to choose the best for your company? Check out these essential criteria:

Platform Interoperability

A reputable partner will offer platform interoperability, meaning they can customize their services to your unique business communication needs versus offering a cookie-cutter approach. ClearlyIP does this for all our partners regardless of platform.

See Data Real-Time

Your chosen SIP provider should make available as much data as possible to you in real-time. This data (call records, for instance) will help you drive your sales, marketing, and customer service. It’s essential to ask to see real-time data of the provider you are considering. I know that at ClearlyIP, we can show this quickly and easily in real-time as this is so important to businesses with remote workers for data tracking.

Security is Key

A reputable SIP trunking provider will focus on protecting your customer’s data. Find out what security measures they have to protect against toll fraud and hacking methods.

BYOIP: Bring Your Own Internet Provider

Top suppliers will allow you to choose your internet provider, which will make the SIP trunking services available in as many locations as possible.

Redundancy: Back-Up Plan

To ensure business continuity, ask about redundancy capabilities to seamlessly route calls in case of network failure.

Access to Customer Support

Your SIP trunking platform should offer expert tech support with service via chat, phone call, email.

System Agnostic Connectivity

Besides offering low-cost options to migrate to SIP trunking, industry leaders can directly configure their service to operate with almost any brand of IP-PBX or softphone.

Advanced Carrier Troubleshooting

The best SIP trunking providers will help you solve any carrier-related issues that may pop up.

Try Before You Buy

Ask if your provider offers a free trial, so you can test the service to experience the benefits of SIP trunking first-hand before investing.


Another criterion to verify is whether they offer comprehensive SIP trunking training to you and other users/administrators of your system.

Competitive Price Offerings

Evaluate the pricing model. Is it straightforward and transparent? Do you have to sign a lengthy contract? Do they charge a monthly fee or require you to make an upfront investment instead? Top partners will offer prepaid and no-contract services with affordable monthly payments per unlimited SIP trunk channel. You can then add or cancel channels at any time and upgrade channels online with a simple control panel.
ClearlyIP offers those options and more, contract or month-to-month, per call path, or per minute. In summary, we have three options you can consider:

  1. Unmetered where you pay by the channel
  2. Metered where you pay by the minute
  3. A hybrid approach of both Metered and Unmetered Call Paths on the Same Location

Check on the level of automation they offer. Are their implementation, monitoring, and maintenance procedures remote and easy to manage? You want to reduce human intervention as much as possible.

With all of these basics covered, you have enough information to choose SIP trunking for your business confidently. Remember, you don’t need to be a networking, IT, or telecommunications expert to take advantage of SIP for your company.

By choosing ClearlyIP as your SIP Trunking Partner, you will receive support to walk you through the implementation process – by yours truly or my gal pal, Em! And we will be there with you as the needs of your business change over time.

The world is your oyster! We have lots of details about this on our SIP Trunking webpage.
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