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WiFi Calling

Enable carrier WiFi Calling over your network with IronWifi.

Overview​

WiFi Calling allows mobile devices to make and receive calls over WiFi instead of cellular networks. IronWifi supports WiFi Calling through:

  • Passpoint/Hotspot 2.0 integration
  • OpenRoaming federation
  • Carrier partnerships for seamless calling
  • Quality of Service for voice traffic

How WiFi Calling Works​

Traditional WiFi Calling​

Without special configuration:

  1. Device connects to WiFi
  2. Mobile carrier routes calls over internet
  3. Works but may have quality issues
  4. Requires open internet access

Carrier WiFi with IronWifi​

With Passpoint/OpenRoaming:

  1. Device automatically connects (no captive portal)
  2. Carrier authenticates device via RADIUS
  3. Voice traffic gets priority (QoS)
  4. Seamless handoff between WiFi and cellular

Benefits​

For Venues​

  • Improved coverage in areas with poor cellular
  • Reduced complaints about call quality
  • Differentiated service for guests
  • Carrier partnerships potential

For Users​

  • Better voice quality in buildings
  • Automatic connection (no login)
  • Seamless handoff WiFi ↔ cellular
  • Free calling over WiFi in roaming areas

Requirements​

Network Requirements​

  • Passpoint-capable access points
  • WPA2/WPA3-Enterprise enabled
  • Quality of Service (QoS) support
  • Sufficient bandwidth for voice

IronWifi Requirements​

  • Passpoint or OpenRoaming subscription
  • RADIUS configuration for carrier authentication
  • QoS policies configured

Device Requirements​

  • WiFi Calling enabled on device
  • Passpoint/Hotspot 2.0 support
  • Carrier that supports WiFi Calling

Configuration​

Step 1: Enable Passpoint​

  1. Log in to IronWifi Console
  2. Navigate to Networks
  3. Create or select a Passpoint profile
  4. Configure Hotspot 2.0 settings

See Passpoint Overview for detailed setup.

Step 2: Configure OpenRoaming (Optional)​

For global roaming:

  1. Enable OpenRoaming in your network
  2. Configure federation settings
  3. Connect to OpenRoaming infrastructure

See OpenRoaming Overview for details.

Step 3: Quality of Service​

Configure QoS for voice traffic:

DSCP Marking:

Voice traffic: EF (46)
Video: AF41 (34)
Best effort: BE (0)

WMM (WiFi Multimedia):

  • Enable WMM on access points
  • Voice → AC_VO (highest priority)
  • Video → AC_VI
  • Best Effort → AC_BE
  • Background → AC_BK

Step 4: RADIUS Attributes​

Configure RADIUS to return appropriate attributes:

Tunnel-Type = VLAN
Tunnel-Medium-Type = IEEE-802
Tunnel-Private-Group-ID = "voice-vlan"

Or for QoS:

Filter-Id = "voice-qos-policy"

Supported Carriers​

WiFi Calling works with carriers that support:

  • Passpoint/Hotspot 2.0
  • OpenRoaming federation
  • Standard SIP over WiFi

Major Carriers:

  • AT&T
  • T-Mobile
  • Verizon
  • Vodafone
  • Orange
  • And many more worldwide

Check with specific carriers for their WiFi Calling support.

Access Point Configuration​

Passpoint Settings​

On your access points, configure:

  1. Hotspot 2.0: Enabled
  2. WPA2/WPA3-Enterprise: Required
  3. RADIUS Server: IronWifi servers
  4. NAI Realm: Configure for carriers
  5. Roaming Consortium OIs: Add relevant OIs

Example: UniFi​

Hotspot 2.0: Enabled
RADIUS Profile: IronWifi
WPA Mode: WPA2 Enterprise
Network Access Identifier Realm: ironwifi.com
Roaming Consortium List: 5A03BA0000, F4F5E8F5F4

See vendor-specific guides:

QoS Best Practices​

Voice Traffic Priority​

  1. Identify voice traffic

    • SIP signaling (UDP 5060)
    • RTP media (UDP 16384-32767)
    • Carrier-specific ports

  2. Mark appropriately

    • DSCP EF for voice
    • Trust upstream markings

  3. Reserve bandwidth

    • Minimum guaranteed for voice
    • Fair queuing for other traffic

Network Design​

  • Separate VLAN for voice (optional)
  • Low latency path to internet
  • Redundant uplinks for reliability
  • Local breakout if possible

Troubleshooting​

Calls Dropping​

  1. Check WiFi signal strength
  2. Verify QoS is working
  3. Check for packet loss
  4. Review bandwidth availability

Poor Call Quality​

  1. Test latency to carrier servers
  2. Check jitter levels (under 30ms ideal)
  3. Verify DSCP markings preserved
  4. Inspect for bandwidth congestion

Device Not Connecting​

  1. Verify Passpoint is configured
  2. Check device supports Passpoint
  3. Confirm carrier WiFi Calling enabled
  4. Review RADIUS authentication logs

Authentication Failures​

  1. Check RADIUS configuration
  2. Verify carrier credentials
  3. Review authentication logs
  4. Test with known-good device

Monitoring​

Key Metrics​

Monitor these for WiFi Calling quality:

MetricTarget
LatencyUnder 50ms
JitterUnder 30ms
Packet LossUnder 1%
MOS ScoreAbove 4.0

IronWifi Monitoring​

Track in IronWifi console:

  • Passpoint authentications
  • Session duration
  • Device types
  • Carrier breakdown

Access Point Monitoring​

Monitor at AP level:

  • Client RSSI
  • Channel utilization
  • Airtime fairness
  • QoS queue statistics

Testing WiFi Calling​

Basic Test​

  1. Enable WiFi Calling on mobile device
  2. Connect to Passpoint network
  3. Make test call
  4. Verify "WiFi" indicator on phone

Quality Test​

  1. Use voice quality testing app
  2. Measure MOS score
  3. Test during peak hours
  4. Compare to cellular quality

Roaming Test​

  1. Walk between APs while on call
  2. Verify seamless handoff
  3. Check for call drops
  4. Test WiFi → Cellular handoff

Security Considerations​

Encryption​

  • WPA2/WPA3-Enterprise required
  • End-to-end encryption by carrier
  • No interception possible at venue

Privacy​

  • Voice traffic encrypted
  • No venue access to call content
  • Carrier handles all voice routing

Compliance​

  • Voice data doesn't touch venue systems
  • CALEA compliance handled by carrier
  • No additional venue obligations

Best Practices​

  1. Deploy Passpoint for automatic connection
  2. Enable QoS for voice priority
  3. Test thoroughly before launch
  4. Monitor continuously for issues
  5. Work with carriers when possible
  6. Educate staff on troubleshooting

Limitations​

Technical Limitations​

  • Requires Passpoint support
  • Not all devices support WiFi Calling
  • Carrier must support WiFi Calling
  • QoS needs end-to-end support

Coverage Considerations​

  • Captive portals interfere with WiFi Calling
  • Open networks may have quality issues
  • Need good WiFi coverage throughout