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Your Ultimate Guide to Direct Routing 

What is direct routing? Your Guide to Direct Routing

If you’re here, you may or may not have heard of direct routing before. You may be wondering what it is, how it works, or why everyone’s talking about it. No matter the reason, we’ve got you covered with the ultimate guide to direct routing.  

What is Direct Routing?  

Any good guide begins with a definition. Direct routing is a technology that lets you make and receive phone calls directly within the Microsoft Teams app. It does this by connecting Teams to your existing phone system, which then connects to the public switched telephone network (PSTN).  

It’s the perfect solution for businesses that want to:  

  • Maintain control over their phone numbers, routing, and call plans,  
  • Keep their current provider,   
  • Create a unified communication system, and   
  • Avoid switching to Microsoft calling plans, which are subscription-based and may not suit their needs. 

How Does Direct Routing Work?  

Direct routing is possible because of session border controllers (SBC). Traditionally, SBCs were physical devices you would install on-premises. But thanks to digital transformation, virtual SBCs are more commonly used these days.   

Here’s how it works:  

Step 1: When a user in Microsoft Teams initiates a call, the platform verifies the user’s credentials, ensuring they’re allowed to make calls. Once verification is complete, the call request is sent to the SBC.  

Step 2: The SBC determines if the user has the required permissions for making the call.  

Step 3: If they do, the SBC decides whether the call should be routed to your current phone system or if it should be handled within Microsoft Teams based on the destination of the call.  

Step 4A: If the call should be routed to your phone system, the SBC converts the call to a “language” (i.e., signaling and media protocols) your system understands and sends it along. Your system will process and complete the call.  

Step 4B: If the call should be handled in Teams, the SBC negotiates with Microsoft Teams to establish the call within the platform, ensuring that all protocols are compatible.  

Step 5: Throughout this process, the SBC monitors the call, logging details for security and auditing purposes. 

Think of the SBC as a mediator. It translates the communication protocols your phone system uses into a language that Microsoft Teams understands and vice versa, ensuring the conversation flows seamlessly between the two. It also acts as a gatekeeper, only allowing authorized communication to and from Teams. 

Inphografic about how direct routing works: Ultimate guide for companies

Direct Routing Deployment Options  

Now that you understand the basics, our guide to direct routing will touch on how this solution can be deployed.  

Option 1: Self-Managed Direct Routing  

These options are the ultimate version of “do it yourself” direct routing.  

1. Hosted On-Premises  

When you choose to host on-premises, you manage all the hardware required for Teams telephony on your property using appropriate hardware.  

  • More Control. You have complete control over your telephony infrastructure, so you can customize it to fit your specific needs.  
  • In-Depth Customization. The ability to design and configure your system according to your preferences.  
  • Extra Security. Physical control over hardware adds an extra layer of security.  
  • Specialized Expertise Required. Managing on-premises systems demands technical expertise in system design and maintenance.  
  • Physical Requirements. Setting up and maintaining physical hardware requires dedicated space.  
  • Complicated Collaboration. Coordinating with multiple third parties can be complex and time-consuming.  

2. Hosted in the Cloud  

Opting for cloud hosting means that your PBX and SBC gateways are hosted virtually.  

  • More Flexibility. There is no need for physical devices or infrastructure, making managing and scaling resources easier.  
  • Cost-Efficiency. Avoid upfront costs associated with physical hardware and reduce maintenance overhead.  
  • Better Accessibility. Access your telephony system from anywhere with an internet connection.  
  • Cloud Access Oversight. Managing cloud access adds complexity to the overall setup.  
  • Telecom Negotiations. Negotiating with telecom carriers for PSTN connectivity can be difficult if you don’t have the proper connections.  
  • Compliance Challenges. Adhering to the proper communication rules in the right places requires in-depth research and planning you may not have the time to conduct.  

Option 2: Service Provider Managed (DRaaS)  

Direct Routing as a Service (DRaaS) is the option where you trust the deployment of your direct routing to a service provider like TeamMate. They handle system design, configuration, infrastructure maintenance, and more. It lets you focus on your mission while providing best-in-class connectivity 24/7. 


  • Hands-Off Management. Outsourcing allows you to focus on your business while experts handle telephony management.  
  • Expertise Access. Benefit from the specialized expertise of service providers for system design and configuration.  
  • Cost Savings. DRaaS eliminates the need for an in-house IT team, specialized hardware, expensive provider contracts, and more – saving you a pretty penny.  


  • Service Fees. You pay regular fees to the DRaaS provider, usually every month. It’s like a fixed cost you can plan for, similar to a monthly subscription. 
  • Potential Premium Pricing. Some DRaaS options may cost more, especially if you require a unique setup. 

Want to Continue Learning About Direct Routing? Download our eBook! 

This blog is just a taste of the knowledge you’ll find in our eBook. With it, you’ll learn:  

  • Why direct routing is so powerful  
  • What kinds of things to look for in a direct routing provider  
  • Which deployment method works best  
  • Plus, a whole lot more  

Download it today to unlock the full potential of Microsoft Teams with direct routing! 

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