Session Border Controller (SBC) for Air Traffic Control (ATC)
An SBC (Session Border Controller) for air traffic control (ATC) is a specialized device that provides secure and resilient voice communication over IP networks, which are replacing older radio systems. It ensures reliability and security by managing, routing, and protecting voice traffic according to aviation standards like ED-137B and C. Key functions include network security, quality of service (QoS) assurance, protocol translation, and load balancing to prevent network failures and ensure uninterrupted communication for controllers.
Key functions and benefits
- Security: SBCs act as a firewall for voice networks, protecting critical ATC infrastructure from unauthorized access and attacks. They provide network separation to isolate specific areas for maintenance or security. SBCs use protocols like TLS and IPSec to secure network traffic and prevent eavesdropping.
- Reliability: SBCs ensure high availability through features like redundant hardware and smart call routing, which redirects calls if a path becomes unavailable, all without the controller noticing.
- Interoperability: SBCs translate between different IP versions (IPv4 and IPv6), different VoIP voice signaling protocols (like SIP and H.323), and voice codecs (like G.729 and G.711) to ensure seamless communication between diverse systems.
- Quality of Service (QoS): SBCs prioritize voice traffic to ensure a high quality of service and maintain clear communication, even on congested networks.
- Traffic management: SBCs balance voice traffic across multiple trunks to the same destination, preventing overload on any single connection. They also monitor the status of other network components to ensure the most efficient call routing.
- Troubleshooting: By collecting data on all voice traffic, SBCs help pinpoint the source of communication issues more quickly, saving time and aggravation during outages.
- Standardization: ATC SBCs are built to comply with aviation standards such as EUROCAE’s ED-137C, which is critical for the interoperability of new IP-based communication systems.
- Scalability: Using industry-standard systems and protocols for logging and administration like syslog and Simple Network Management Protocol (SNMP) allows large numbers of SBCs to be managed via a remote server, making configuration and monitoring of the network from a central point possible even in large deployments with many devices.
How it works in ATC
- An ATC SBC sits at the boundary between different parts of the voice network.
- It handles the secure connection between Air Traffic Service Units (ATSUs) and other ATC systems, ensuring that only authorized and secure voice traffic is allowed through.
- When an air traffic controller needs to speak with an aircraft or another controller, the call goes through the SBC.
- The SBC then manages the call setup, media transmission, and call teardown, providing security, QoS, and reliability throughout the conversation.
- It can also support both legacy TDM-based systems and modern VoIP-based systems, allowing for a smoother transition to IP-based communication.