Exam MS-721 topic 1 question 64 discussion

Actual exam question from Microsoft's MS-721

Question #: 64
Topic #: 1

You have a Microsoft Teams Phone deployment.

You have a PBX that connects to the PSTN by using an E1/T1 Primary Rate Interface (PRI).

You plan to migrate to Direct Routing by using the existing PSTN services.

What should you install upstream of the PBX?

A. a virtual Session Border Controller (SBC)
B. an FXO SIP Analog Telephony Adapter (ATA)
C. a physical Session Border Controller (SBC)
D. a Session Border Controller (SBC) in Azure

Show Suggested Answer

Suggested Answer: C 🗳️

by Nico282 at Jan. 17, 2024, 10:26 p.m.

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shah2

5 months, 3 weeks ago

Selected Answer: C

To migrate to Direct Routing using your existing PSTN services, you should install a physical Session Border Controller (SBC) upstream of the PBX. This will allow you to connect your existing PSTN services to Microsoft Teams Phone.

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Nico282

11 months, 1 week ago

All other things being equal, a virtual SBC (whether hosted in Azure or not) or physical SBC is required for Direct Routing. But as far as I know, the only SBC's that are available with PRI interfaces (as opposed to SIP trunking) are physical. An ATA FXO SIP interface may or may not be required, depending on the specific SBC, but an SBC is certainly required. Therefore C is indeed the best answer IMO.

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