Calling Plans vs Direct Routing

A significant decision for any organization looking to deploy Teams voice workloads is whether they will use Calling Plans, Direct Routing, or some combination of the two. I couldn’t find a decent comparison between the options, so I wrote this one.

Calling Plans

Calling plans are where your PSTN calling services are provided by Microsoft. Essentially, Microsoft becomes your telco (telephone company). Currently Calling Plans are only available in less than a dozen major countries, with no plans to roll out service to more.

Direct Routing

Direct Routing is where you connect a certified SBC to Microsoft Teams, and then any service you wish can connect to the SBC. This includes PSTN access from a telco, but can also include other PBXs (I’m looking at you Avaya and Cisco) or analog devices like enterphones/door buzzers and overhead paging.

Mix and Match

A user can be assigned a phone number from Calling Plans or Direct Routing. This is a per-user decision – Kim in cube 123 can be on Calling Plans, while Sam in cube 124 is on Direct Routing.

Note here that we’re talking about the user’s phone number. A user who’s PSTN services are provided by Calling Plans can use Direct Routing to reach an Avaya system or analog devices. Calling Plan users cannot be reached via the Direct Routing trunk. If an Avaya user calls a Calling Plan user, the call must be routed via the PSTN.

Here are some other comparisons:

Calling Plan

Direct Routing

Pay per user, per month. Multiple plans available, minutes pooled between users in same country with same plan.

Usually pay per channel. Generally cheaper as more users are added.

No channel limit

Connections will have hard channel limits, or limits with burst capability, but are not unlimited

Users are allocated a number of minutes per month

Generally no minute limitation

Microsoft is your telco, billed with the rest of O365 services

Can use any telco service available, separate bill from the telco

Does not require additional equipment

Requires a Session Border Controller – purchase costs (physical or virtual), ongoing maintenance, channel limits, hosting costs (in your office, a datacenter, or cloud based). Multiple will be required for HA. Will need SBC located in same country as services (typically)

Some telcos offer hosted SBC services along with SIP trunk services.

Cannot provide access to on-prem equipment

Can provide access to on-prem equipment

May have limited advanced emergency calling capabilities for your country

Excellent options for emergency calling in all countries. Usually via SBC but sometimes via feature-rich 3rd party integration.

Limited number translation inbound/outbound

SBC provides for wide array of number translation options

Hit me up in the comments or @bumpinthenet on Twitter and let me know if I’ve missed anything!

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