What is an SBC and when do you need one?
An SBC is the gatekeeper of your telephony.
A Session Border Controller (SBC) sits between your telephony platform and your provider’s phone network. It secures the connection, lets systems work together that speak slightly differently, and routes calls the right way.
Whether you need one yourself depends on how you connect to the phone network.
With Teams, only for Direct Routing.
No SBC of your own
Microsoft provides the numbers and calling minutes. You don’t need an SBC of your own.
More about Teams Phone →No SBC of your own
A certified operator has already built the connection with Teams. You simply take a subscription.
More about voice and connectivity →A certified SBC
You connect your own provider through an SBC certified by Microsoft. You manage it yourself, have a partner manage it, or take it as a service.
More about voice and connectivity →You can also combine routes. For example Operator Connect for most users, and Direct Routing for a contact center, an older phone system or analogue devices.
With Zoom, only for BYOC on your own premises.
You use Zoom Phone with Zoom numbers, with your own provider through the cloud (BYOC-C), or through your own SBC on premises (BYOC-P). Only in that last case do you manage an SBC yourself. It must be on Zoom’s list of supported equipment.
Four jobs of an SBC.
- SecurityEncrypted connections (TLS and SRTP), and no open door to your network.
- TranslationSystems that speak slightly different SIP still work together.
- RoutingCalls go to the right provider, phone system or contact center.
- SurvivabilityWith a Survivable Branch Appliance, Teams users at a branch keep calling if the internet goes down.
Five things when choosing an SBC.
- CertifiedMicrosoft supports Direct Routing only with certified SBCs. Certification applies per firmware version.
- Hardware, virtual or cloudVendors such as AudioCodes, Ribbon, Oracle and Cisco offer hardware, virtual and cloud versions.
- RedundancyTwo SBCs or a cloud option prevent a single failure from stopping all your calls.
- CertificatesIn 2026 Microsoft moved to a new certificate authority. If your SBC doesn’t trust it, connections fail.
- Keeping upFirmware, certificates and security advisories need follow-up. Agree who does that.
The checklist as a PDF.
Seven questions to take to your meeting or pass on to a colleague. Enter your name and email address and the PDF opens right away.
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We check whether you need an SBC.
We look at which route to the phone network fits you, whether you need an SBC and who manages it. Independent, and we also guide you through implementation and management.