Session Border Controller (SBC) – Security for Your VoIP Telephony

What is a Session Border Controller?

A Session Border Controller sits at the boundary between internal and external IP networks, controlling, protecting, and monitoring real-time communication such as VoIP calls. It terminates and mediates SIP signaling as well as media streams, providing central functions for security, routing, quality, and interoperability.

Typical SBC tasks include protection against fraud and Denial-of-Service attacks, bandwidth and codec control, and hiding the internal topology (Topology Hiding). Modern SBCs also support transcoding, recording, load balancing, and integration into existing UC and collaboration environments.

Why Enterprises and Institutions Need an SBC

As VoIP usage grows, so does the complexity and attack risk at the IP boundary of enterprises and service providers. A Session Border Controller bundles security, routing, and control functions at a central point, making communication more robust and predictable.

SBCs help meet quality requirements (QoS) and compliance regulations, especially in regulated or security-critical environments. They also enable gradual capacity scaling without jeopardizing the existing VoIP infrastructure.

Key Functions of a Session Border Controller / SBC

• Signaling and media proxy: Separation of internal infrastructure from external networks through proxying of SIP signaling and RTP/media

• Firewall functionality: Stateful inspection and packet filtering specifically for SIP and RTP traffic

• NAT traversal: Enables connections through NAT/firewall boundaries using ALG, STUN, TURN, or ICE

• Interoperability: Protocol and codec transcoding, SIP normalization, and header manipulation for compatibility with different endpoints and providers

• Quality of Service (QoS): Prioritization and traffic shaping for voice and video quality

Deployment Scenarios for Session Border Controllers

• Provider boundary: SBCs as transition points between service providers and customer networks for security and billing

• Enterprise networks: Protection of internal IP PBX systems when connecting to external partners or cloud UC platforms

• Cloud integration: Hybrid environments where on-premises PBX systems are securely connected to cloud telephony via SBC

• Roaming and mobile clients: Secure handling of mobile VoIP clients and SIP trunks

ABC SBC: Scalable Session Border Control

The FRAFOS ABC SBC is a scalable Session Border Controller for VoIP service providers and enterprises, which can be operated on high-end hardware, appliances, and virtual machines alike. It combines secure Session Border Control with signaling mediation, call routing, and an integrated media server platform for announcements, transcoding, and recording.

Key functions include centralized management of multiple SBCs from one location, infrastructure relief through Registration Offload, rate limiting, content control, and media control to defend against fraud and DoS attacks. Open REST interfaces enable integration of external routing and authentication logic as well as control of announcements.

secunetSBC: Highest VoIP Security

The secunetSBC targets institutions and organizations that require the maximum security level for their VoIP communication. It combines FRAFOS SBC technology with the certified secunetWall firewall and protects data streams at network, transport, voice, and application levels.

The secunetSBC is certified by the Federal Office for Information Security (BSI) with certification ID BSI-DSZ-CC-1089 according to CC EAL 4+, providing proven resistance to attacks. Additionally, interoperability with Mitel is certified, facilitating integration into existing communication systems.

Advantages of Session Border Controllers: ABC SBC and secunetSBC

ABC SBC and secunetSBC address different requirement profiles but both are based on mature Session Border Control technology. While the ABC SBC is particularly designed for scalability, flexible media functions, and multi-tenancy scenarios, the secunetSBC focuses on the highest security and compliance requirements.

Enterprises can choose the appropriate SBC solution depending on the deployment scenario – from classic enterprise VoIP environments to government and high-security networks – and receive central functions such as secure VoIP telephony, high availability, and easy administration in both cases.

Comparison of FRAFOS Session Border Controllers: ABC SBC and secunetSBC

A Session Border Controller is therefore indispensable for the secure provision of VoIP services. By combining signaling and media control, encryption, attack detection, and routing policies, the SBC provides comprehensive protection, improves interoperability, and ensures voice quality. When planning and operating, encryption, restrictive policies, monitoring, and regular updates should be the focus to ensure VoIP security long-term.

Feature	ABC SBC	secunetSBC
Focus	Scalable Session Border Control for providers and enterprises	Highest-security VoIP communication for institutions
Platform	Hardware, appliance, virtual machine	Appliance with secunetWall firewall
Media Functions	Announcements, transcoding, recording	Audio/video gateway, security focus
Security	Fraud and DoS protection, topology hiding, content and media control	BSI CC EAL 4+ certified, double-protected by firewall and SBC
Management	Centralized management of multiple SBCs via Cluster Configuration Manager	GUI-based administration, remote updates and configuration
High Availability	Active/hot-standby, load balancing	High availability, failover, geo-redundancy
Interoperability	Open REST interfaces, MS Teams Direct Routing	Certified interoperability with Mitel

Conclusion

A Session Border Controller is therefore indispensable for the secure provision of VoIP services. By combining signaling and media control, encryption, attack detection, and routing policies, the SBC provides comprehensive protection, improves interoperability, and ensures voice quality. When planning and operating, encryption, restrictive policies, monitoring, and regular updates should be the focus to ensure VoIP security long-term.

Personal SBC Demo

Enterprises and institutions that want to strengthen their VoIP perimeter and evaluate the appropriate SBC functions for their environment should experience both solutions in a live setting. A personal demo shows how ABC SBC or secunetSBC can be concretely integrated into your telephony infrastructure – from security requirements to routing and connection of existing communication platforms.

Request a personal demo now and together find the right Session Border Controller for your requirements:

Request Live Demo

FAQ Session Border Controller (SBC):

Which deployment areas are particularly suitable for ABC SBC?

The ABC SBC is ideal for VoIP service providers and enterprises seeking a flexible, scalable solution for secure voice communication with integrated media functions such as transcoding and recording. It supports multi-tenancy and high availability, suitable for both small and large networks.

How easy are the management and configuration of the SBC solutions?

The ABC SBC offers a Cluster Configuration Manager for centralized management of multiple SBCs and open REST interfaces for automation. The secunetSBC features a user-friendly GUI with central remote control and granular configuration options.

Do both SBCs support modern VoIP standards and integrations?

Yes, both ABC SBC and secunetSBC support a wide range of audio codecs, SIP standards, and offer integrations such as Microsoft Teams Direct Routing (ABC SBC) or certified SIP interoperability with Mitel (secunetSBC).

How can I test the right SBC for my company?

FRAFOS offers personal demos for ABC SBC and secunetSBC, where you can experience the functions, security features, and integration into your infrastructure live. A demo can be requested directly via https://www.frafos.com/contact.