Direct Routing Versus Calling Plan for Voice in Microsoft Teams

Mike Hanks
August 6, 2020

As one of the fastest growing collaboration products in the world, Microsoft Teams is being used for internal communication, meetings, and document management. With Microsoft’s announcement of voice capabilities for the platform, there has been a growing buzz about a key technology that will help businesses adopt Teams: Direct Routing.

What is Direct Routing?

Direct routing refers to the process of routing Microsoft Teams voice calls directly to the PSTN. Though Teams is meant to be chiefly used as an internal communication platform, it can be set up to be a fully functioning Phone System with either direct routing or a Microsoft calling plan.

Microsoft Calling Plan

A Microsoft calling plan is a road to the PSTN managed entirely by Microsoft. This option is expensive and only available (at time of writing) in a few territories. Porting numbers can also be confusing and time consuming, with no dedicated contact to help with the process.

Microsoft Direct Routing

Direct Routing allows you to connect Teams to a range of voice service providers. This means being able to take advantage of cheaper call rates, more flexibility and better support. It’s also helpful for users locked into existing contracts with PSTN providers such as Verizon and CenturyLink, allowing them to use Teams without violating the contract in any capacity.

Many businesses find the direct routing model much more appealing as it gives them the flexibility to choose their own provider while integrating with other enterprise systems and taking advantage of Microsoft Teams’ phone system features.

How Direct Routing Works

Direct Routing works by combining the Teams system to the PSTN using two key elements: a Session Border Controller and SIP Trunks.


Session Border Controller (SBC)

Often described as a “firewall for VoIP”, an SBC is used to guard the “borders” between different networks, making sure data is transferred properly between them. More importantly, they’re designed provide a layer of security and protection from attacks and breaches.

> Read: How Microsoft Keeps Your Data Secure.

SBC’s used to be almost exclusively located on premise, but as time goes on, more and more are cloud-based instead. Cloud-based SBC’s offer a much higher level of flexibility and reliability with lower up-front costs.

SIP Trunks

These are devices that connect a business phone system to the internet and the PSTN. SIP Trunks are an essential component for connecting any PBX to the PSTN and a valid alternative to using a hosted “all-in-one” system.

Note that some providers only offer an SBC without SIP Trunks. This means you’ll need to find a separate supplier to provide the trunks, adding complexity and cost.

Who Direct Routing is for

Direct Routing is primarily designed for organizations set on using Teams as a phone system. Any business that matches one of the following criteria is a strong candidate for considering direct routing:

Strong User of Teams

This one is obvious, but any business that is deeply embedded in using Microsoft Teams for internal communications can more easily use the platform for their external communication too. This also means less of a need for a separate PBX (and all the costs entailed) together with better integration between systems.

Limited in-house Expertise

Any business with little to no IT personnel on hand may want external support when considering using Teams as a phone system . Experienced providers and Microsoft partners can help manage the solution and make sure your users are able to get the fullest out of Teams.

Users Want More Flexibility

Microsoft’s own calling plan isn’t a flexible one. With very strict guidelines on carrier and location, there’s not much room for negotiation. This makes direct routing the obvious choice for businesses making excessive amounts of outbound calls, especially to international locations.

The Cost of Direct Routing

Direct routing costs largely depend on carrier rates and individual circumstances. This means there isn’t a one-size-fits-all price for this solution. However, due to its cheaper recurring prices, Direct Routing will almost always cost less per user per month than Microsoft’s own Calling Plans.

Benefits of Direct Routing

Direct routing through Microsoft Teams provides many benefits. The idea of using Teams as a phone system is a huge step forward for businesses who want to combine all their internal and external communications into one tightly knit system. In this way, it embodies a true unified communications solution.

Direct Routing also means third party integration, which has plenty of positive aspects. Choosing the right provider can save you huge amounts of upfront and ongoing fees and gain a large amount of expertise and reliability.

Along with that, switching to Teams as a phone system doesn’t mean losing your old numbers. Microsoft will allow you to port your old numbers and keep using them in Teams. Should you choose not to, ordering new DDI’s is also an option, and can be done just as easily.

Setting up Direct Routing

With Direct Routing, the setup is remarkably painless. A direct routing system can be integrated to your existing phones systems and analog points, even emergency calling points. It also allows for a phased transition to Teams so that calls made between fully migrated Teams users and non-migrated phone system users don’t hamper the user experience. All of this will be made quick and easy with the help of an experienced partner like Continuant.

A third-party integrator will help you port your numbers, or order new ones if you decide to change carriers. Once everything in Teams is cleared with your provider, we’ll deploy your SIP trunks and new SBC’s. If all goes well, this step should take less than a day. From there, it’s all a matter of informing your provider and training your staff.

Start your journey to Microsoft Teams

A Microsoft Teams deployment requires you to fully understand your business’ needs. For Teams’ voice capabilities that means knowing whether Direct Routing or a Calling Plan better supports your business. Is a Calling Plan available in your area? What service providers are you using and are there contractual obligations? What analog endpoints need to be supported? Are there other third-party integrations that need to be included?

With 26+ years of experience in legacy voice and having won the 2020 Microsoft Partner of the Year Award for Calling & Meetings in Microsoft Teams, we are well-positioned to help you answer all these questions and start your journey to Microsoft Teams.

Schedule a 30-minute technology assessment today to find out what the transition to Microsoft Teams could look like for your organization.

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