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Integration
Cybertel Bridge provides a comprehensive range of integration capabilities covering interfaces and systems essential to mission-critical service deployment, including interworking functions, QoS control, authentication, OSS, and multimedia delivery, ensuring seamless compatibility and network-wide interoperability.
Cx Interface
Cx interface enables communication between the MCX SIP Core and Home Subscriber Server (HSS) within an IMS (IP Multimedia Subsystem) network.
It supports subscriber authentication, authorization and USIM-based user identity management using the IMS-AKA procedure.
Through this integration, Cybertel MCX system can authenticate users based on their IMSI, IMPI and IMPU — critical for providing secure and reliable access to Mission Critical Services (MCPTT, MCVideo, MCData).
Key Benefits
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Seamless USIM-based Authentication
IMS-AKA with Cx enables VoLTE-level security for MCX users.
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Secure SIP Registration
Ensures that only authorized users can access MCX services.
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Dual-mode Support
Supports both USIM-based and ID/password-based login models.
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Access Token Mapping
Binds MC Service ID with IMS Public User Identity (IMPU) securely.
Use Cases
- First responder logging into MCX with SIM-based authentication
- Secure authentication for dual-mode MCX/VoLTE terminals
- Interoperability with national mobile networks using HSS
Integration Reference Point
MCX AS ↔ HSS Communication via Cx
Cx interface is a Diameter-based protocol (3GPP TS 29.229) used by the SIP Core within the MCX system to retrieve subscriber profile and authentication vectors from the HSS.
Reference Point
Cx Interface: SIP Core (MCX) ↔ HSS
| Function | Description |
|---|---|
| User Authorization Request (UAR) | Sent to check if the subscriber is valid |
| Multimedia Auth Request (MAR) | Requests authentication vectors (IK, CK) |
| Server Assignment (SAR) | Assigns or removes user-server association |
Authentication Procedure (IMS-AKA)
- SIP Initial REGISTER sent from UE with IMPU & IMPI
- SIP Core sends UAR & MAR to HSS via Cx
- HSS responds with authentication vectors
- UE calculates RES and responds
- If RES = expected response, registration succeeds
Access token includes MC Service ID, mapped to IMPU
Flexible Login Options
- USIM-based IMS-AKA Login (preferred in LTE/5G public safety networks)
- ID/Password Login via Cybertel CSC (alternative for non-USIM devices)
IPSec and SIP Digest Authentication also supported.
Cybertel HSS Integration Highlights
- Cx Diameter Stack Built into SIP Core Fully compliant with HSS protocols for IMS-AKA and session control
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Support for USIM Provisioning
· IMSI, IMPU, IMPI registered to HSS
· IMS Profile configured for MCX application use
- Automatic Token Binding MC Service ID securely mapped to IMPU after SIP registration
Security Features
- IMS-AKA with IK/CK key generation
- SIP Digest MD5 Challenge/Response
- Optional IPSec tunnel setup for SIP signalling
- Token-based 3rd-party registration to MCX server
Why Choose Cybertel?
- IMS-ready SIP Core with Cx support
- Seamless integration with national MNO HSS
- Supports fallback login models
- Proven deployments in large-scale public safety networks
