Teams Direct Routing SBC License Fees & TCO
By: Derek Harris | Dialvice CEO | 30+ years’ experience
👉 5 mins saves you 15+ hours!
Updated September 4, 2026
The real cost of Session Border Controllers in Microsoft Teams
When moving business calling to Microsoft Teams, you have three primary paths:
- Microsoft Calling Plans: Native plans ($17/user/mo) offer basic calling, but become expensive at scale and lack advanced features.
- Custom Direct Routing: Buying and hosting your own Session Border Controller (SBC) to connect Teams to a carrier or on-prem PBX.
- 3rd-Party Provider: Connecting a managed cloud phone system (via Direct Connect or Operator Connect) with built-in SBC infrastructure.
Direct Routing paths can start at 25+ users, but true ROI against custom SBC costs typically hits at 150+ seats.
However, building custom SBCs (Path #2) introduces unexpected software licensing fees, VM hosting costs, and setup labor.
Understanding these expenses helps you build an accurate budget—or choose a 3rd-party option instead.
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👉 Related: Explore our Complete Cloud Phone System Guide and the MS Teams Cloud Phone: Legacy Fax & Paging Guide.
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Key Takeaways & Quick Links
- Concurrent Call Model: Software licenses scale on simultaneous call capacity (active sessions), not overall user counts.
- Core Infrastructure Gate: Direct Routing requires a certified SBC (AudioCodes, Ribbon, Oracle, or TelcoBridges) deployed on physical hardware or cloud VMs.
- Required License Stack: Direct Routing sits on top of your base Microsoft 365 seat plus a Teams Phone Standard add-on ($10/user/month).
- Break-Even Point: Organizations with 150+ seats generally recover upfront SBC configuration expenses in 12 to 18 months via wholesale SIP trunk rates.
The short answer ⚡
Microsoft Teams Direct Routing SBC licenses typically run $1,500 to $10,000+ upfront for session capacity, plus 15%–20% annual maintenance.
Paired with Teams Phone Standard ($10/user/month) and wholesale SIP trunks, it offers significant long-term savings for organizations with over 150 users.
Path Overview:
Microsoft Teams Cloud ➡️ (SIP / TLS / SRTP) ➡️ Certified Virtual or Hardware SBC ➡️ (SIP Trunk / Analog) ➡️ Carrier / Local PBX
Manufacturing scenario: 40% phone bill savings
A 75-user manufacturer with two facilities needed to replace an aging PBX. Office staff already used Teams daily, making a voice migration logical.
Microsoft’s native Domestic Calling Plan ($17/user/month) totaled $15,300 annually for 75 seats.
Worse, it added steep international rates for overseas suppliers and lacked native support for factory-floor paging or warehouse intercoms.
Instead of building complex custom SBCs in Azure, they chose a managed 3rd-party cloud phone provider integrated into Teams via Direct Connect.
The provider supplied a managed hybrid gateway for analog gear, handled all SBC routing, and delivered wholesale voice rates.
This slashed their annual phone bill by 40%+ while eliminating upfront SBC software costs entirely.
💡 Derek’s Pro Tip: Got copper lines running to elevators or alarms? Look into a digital POTS Replacement solution to save money, while still being compliant.
SBC license models: Concurrent Sessions vs. Per-Port Pricing
Unlike traditional unified communications platforms where you buy a flat license for every human seat, Session Border Controllers are engineered around traffic density.
You do not buy an SBC license for every employee. You license the system based on how many simultaneous phone calls (concurrent sessions) your business handles at peak volume.
Here is how certified SBC vendors structure their software licensing models:
| Metric | How It Works | Cost Range | Best For |
|---|---|---|---|
| Concurrent Session (CS) | Billed by maximum active calls (e.g., 20, 50, 100 lines). | $1,200 – $6,500 / tier | Mid-market & multi-site businesses |
| Per-User / Hosted | Flat monthly fee per extension via hosted SBC-as-a-Service providers. | $1.50 – $4.00 / user / mo | SMBs seeking fixed OpEx predictability |
| Capacity Blocks | License add-ons unlocking extra channels as traffic grows. | $500 – $2,000 / 10 channels | Expanding operations with seasonal call spikes |
| High-Availability (HA) | Mirrored primary and secondary instances for 99.999% uptime. | 1.5x – 2x base software | Healthcare, finance, & emergency services |
Hardware Appliances vs. Cloud Virtual SBC Software
Choosing where your SBC lives changes both your upfront CapEx and your ongoing admin overhead.
You have two primary deployment paths:
Dedicated Hardware Appliances
Hardware appliances from vendors like AudioCodes (Mediant) or Ribbon (Edge) include built-in digital signal processors (DSPs) for media transcoding.
They also feature native FXS/FXO ports to connect legacy gear like elevators, faxes, and overhead speakers.
Trade-off: Higher initial capital investment ($3,000 – $15,000+) and eventual hardware obsolescence.
Virtual & Cloud Software SBCs
Virtual instances (AudioCodes VE, Ribbon SWe Lite, TelcoBridges ProSBC) running on VMware, Hyper-V, AWS, or Azure scale rapidly via digital license keys.
Trade-off: Eliminates physical hardware, but requires monthly cloud VM hosting fees and active firewall maintenance against SIP scanning attacks.
💡 Derek’s Pro Tip: If your locations use fax machines, gate intercoms, or analog paging, you don’t need a full on-site hardware SBC. Deploying a low-cost Analog Telephone Adapter (ATA) or media gateway with FXS ports connects those legacy endpoints to Teams reliably.
Total Cost of Ownership (TCO) stack
Evaluating Direct Routing purely on SBC software license costs misses the broader financial picture. To build an accurate 3-year IT budget, you must stack all required layers together:
| Cost Layer | Pricing Model | Monthly Impact (100 Users) |
|---|---|---|
| 365 Base License | Business Standard / E3 / E5 | $12.50 – $42.00 / user |
| Teams Phone Standard | Required PBX license ($10/user x 100 seats) | $10.00 / user ($1,000 total) |
| SBC License & Support | Software fee amortized (36 mo) + maintenance | $100 – $300 / mo |
| Cloud VM Hosting | Azure / AWS compute instance | $50 – $150 / mo |
| Wholesale SIP Trunking / PSTN Carrier | Per-minute or bundled channels | $2.00 – $5.00 / user ($200 – $500 total) |
| Total Voice Stack | Combined monthly TCO | $25.00 – $58.00 / user / mo |
How to size and license your SBC correctly
Over-provisioning your SBC concurrent session licenses wastes capital, while under-provisioning causes dropped calls during peak morning hours. Follow this sizing methodology:
- Calculate peak call ratios: As a general rule, 10% to 15% of knowledge workers call simultaneously during peak hours (30 to 45 sessions for a 300-person office). Shift-heavy manufacturing or dispatch environments should size for 20% to 25% peak concurrency.
- Plan for transcoding: If your carrier uses standard G.711 but mobile users require compressed codecs like G.729, your SBC must transcode media in real time. Ensure your license covers this without overloading CPU limits.
- Deploy high-availability pairs: Avoid single points of failure. Run an active-standby pair across two cloud availability zones or physical servers to prevent downtime.
- Consider managed SBC-as-a-Service: If managing TLS certificates, firmware updates, and SIP security internally isn’t practical, let a provider handle licensing and monitoring for a flat monthly fee.
💡 Derek’s Pro Tip: Check if Operator Connect fits your workflow before building custom Direct Routing. Operator Connect offers similar wholesale pricing, but certified carriers manage the SBC infrastructure behind the scenes—saving you upfront software and management costs.
Next steps for your voice plan
Direct Routing gives you complete carrier control, but configuring SIP trunks and managing custom SBC hardware adds unnecessary operational tax for many teams.
An integrated 3rd-party cloud phone system delivers that exact same Teams experience—with wholesale voice rates and $0 in infrastructure overhead.
Let Dialvice find you the exact solution, without the endless research, sales call and spam. 👇
Frequently Asked Questions
Do I need an SBC license for every Microsoft Teams user?
No. SBCs are licensed by concurrent sessions (simultaneous active calls), not total user count. A 500-person organization usually only needs a 50-to-75 session license.
What is the main difference between Calling Plans and Direct Routing?
Microsoft Calling Plans bundle minutes and carrier service directly inside Teams with no infrastructure required. Direct Routing connects Teams to third-party SIP carriers or existing PBX hardware using an SBC, lowering per-minute costs and supporting legacy equipment.
Can I run a certified Teams SBC natively in AWS or Azure?
Yes. Leading vendors like AudioCodes, Ribbon, and TelcoBridges offer virtualized software editions designed specifically for Microsoft Azure and AWS deployments.
Why is an SBC required for Microsoft Teams Direct Routing?
Teams relies on encrypted web protocols (SIP over TLS and SRTP), while traditional carriers use standard PSTN signaling. An SBC bridges these networks securely, managing encryption, firewall traversal, and call routing.
How does Operator Connect compare to Direct Routing?
Operator Connect uses Direct Routing architecture under the hood, but the carrier manages the SBC infrastructure and security. Instead of buying software or hardware, you select a certified carrier and provision numbers directly inside the Teams Admin Center.
What happens if our active call volume exceeds our licensed SBC session limit?
Any call attempted beyond your licensed concurrent session limit will receive a busy signal or be rejected at the SIP gateway. Always build a 15%–20% buffer into your session licensing to handle unexpected traffic spikes.
Notice: For informational purposes only. Emergency systems must be installed by certified professionals to ensure local code compliance.
