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What is a SBC?

 In Blog, General, Unified Communications, Voice



SBC stands for “Session Border Controller”. It’s a device typically found in an organization’s telephony networks, facilitating security, quality of service, data-based communications (VoIP, FoIP, Video Calls, etc), and other systems.

An SBC can either be its own distinct piece of hardware, or just one software function of a more complex device.


What does a session border controller do?

SBCs can be a little hard to define because the exact functions of a given session border controller can vary with the producer and model. In general, they cover these areas:

  • Securing Against Attack
    SBCs can act as a critical line of firewall defense against malicious intrusion by hackers, DoS/DDoS attacks, etc.
  • Quality of Service via Gatekeeper Management of Calls & Data Usage
    An SBC can control the allocation of bandwidth and calls to ensure critical tasks are not overwhelmed or degraded by the data load of others. SBCs can recognize types of incoming data and automatically route them to the appropriate devices (fax systems, phones, PBX, servers, etc).
  • Facilitating Data-Based Communications (VoIP, FoIP, Video Calls, etc)

SBCs can be an important part of an organization’s SIP Trunking setup (what is SIP Trunking?) acting as a sort of router to (among other things) facilitate calls collected via an organization’s hard phone/PBX systems.  This happens on the IP network rather where bandwidth is managed dynamically to ensure calls remain clear.

  • Compliance with Phone Regulations
    SBCs can ensure the system is subject to law-mandated interactions such as the prioritization of emergency calls and provide support for authorized interception (wiretapping) of specific callers under court order.

SBCs are also used at the service provider level to regulate network usage, collect statistics on individual account usage for billing purposes, enforce the details of forwarding agreements with other providers, protect against phone fraud, etc.


What’s happening with Microsoft’s support for SBCs in Microsoft Exchange Online?

If your organization uses an SBC together with Microsoft Exchange Online for Unified Messaging (UM), there’s been an important development concerning your SBC. Microsoft has announced that they will be discontinuing all SBC support on Dec 1st, 2019. This means that if you’re using a SBC to bridge the gap between a PBX and Exchange Online, your UM solution will become inoperable.

Microsoft has suggested three possible solutions; transitioning your telephony infrastructure to Office 365 in the Cloud, deploying an on Premises Skype for Business Server (and eventually upgrading to Enterprise Voice), or moving to a 3rd Party Voicemail System that can bridge the gap between your PBX and Exchange using an API rather than a SBC.


Preserve Your Unified Messaging System with CX-E

Our 3rd party voicemail and unified communications system, CX-E, will bridge the gap between your PBX and Microsoft Exchange.

In addition to preserving unified messaging functionality by replacing an SBC with an API, CX-E also brings a host of other powerful features, including:

  • Industry leading UC interoperability
  • Interactive voice response (IVR) applications and voice recognition automated attendants to save staff time & empower customers
  • Mobile application with a virtual personal assistant to boost call completion by allowing employees to be reachable anywhere
  • Informal call center that functions beyond what’s provided by simple hunt groups.


Read More About the Microsoft Exchange Online SBC Changes


If you would like to learn more about how this system can cost-effectively preserve UM functionality without a costly rip & replace, reach out to our team and we’ll be happy to answer any questions you may have.



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