Kamailio & FreeSWITCH Clustering: High Availability and Load Balancing Architecture

1. Why High Availability Matters in Telephony

Telecommunications demands five-nines (99.999%) availability. A single hardware failure must never terminate active customer conversations. SanalPBX solves this via decoupled signaling and media clustering.

2. Core Architectural Layers

• Kamailio Edge SIP Load Balancer: Handles stateless SIP registration and routes calls across media clusters using the dispatcher module.
• FreeSWITCH B2BUA Media Pool: Stateless media workers that process IVR playback, call recordings, and WebRTC audio bridging.
• Distributed Redis & Database State: Real-time extension statuses and queue memberships persist across redundant nodes.