Session Border Control in Enterprises

Overview

The mass adoption of IP-based voice and video services is now being driven by improvements in quality and features, in addition to the well-known cost advantage.

For the enterprise market, reliability and security are key factors. These present growing challenges as traffic volumes over all network links (internal, inter-site, and Internet) rise.

Enterprises also need to offer their staff a consistent experience whether they are in the office, at home or on the road. This mobility requires deep integration into the global next generation telecommunication network – blurring the boundary between the enterprise and carrier networks.

As a result, enterprises are increasingly deploying Session Border Controllers (SBCs) to protect their network border and retain control of this new network environment. For example, Infonetics reports that the enterprise session border controller market bucked the overall negative spending environment to grow more than 50% in 2009 over 2008.[1]

By deploying Session Border Controllers, enterprises can ensure QoS for business-critical services, protecting sensitive data and servers, and optimizing costs through fine-grained access policy, per-user limits, and intelligent routing.

Session Border Controllers enable the use of otherwise incompatible devices and services, so minimizing disruption and upgrade cost when rolling out new services. SBCs can interwork between enterprise services (e.g. PBX), carriers (IMS or non-IMS), hosted services, other third-parties and a wide range of client devices. For example, SBCs can enable an H.323 based conferencing server to support SIP phones and tunnel services through NATs and firewalls.

Session Border Controllers also include extensive monitoring capabilities to enable reconciliation with carrier charges, for management accounting, and to record usage for compliance.

Metaswitch has extensive experience in supplying Session Border Control (SBC) software products to communications equipment manufacturers, enabling them to build SBC products that meet enterprise requirements.

Features and Benefits

The Metaswitch Session Border Controller solution for IMS offers the following features and benefits.

• Protects from malicious and faulty devices – controlling signaling access to the enterprise network, and normalizing signaling traffic (call attempt rate limits, concurrency limits (number of calls, bandwidth requirements), ANI / DNIS).
• Controls routing of traffic to peer networks and subscribers, including prioritized location-aware handling of emergency calls.
• Maximizes usable capacity of shared-usage, bandwidth-constrained links using flexible enterprise-configured policy to apply QoS marking, bandwidth limits and prioritization to signaling and media traffic based on numerous inputs including: end-user identity, network loading, and resources requested.
• Enforces privacy of operator and customer information – strips private headers from messages leaving the core, enforces security policy on trusted and untrusted links, provides NAT for private to public address mapping, and topology hiding.
• Monitors usage and generates billing records for the media resources used by each call – the billing records are cached locally in the event of failure to contact a billing server.
• Supports wire-tapping by national intelligence agencies.
• Enables interworking with non-IMS carriers, enterprises and end-users, including H.323 / SIP interworking, DTMF and codec interworking, and NAT and firewall traversal.
• Supports multiple standard profiles e.g. IMS, SIP, H.323, including interworking between variants, extended with multi-layer policy rules and flexible customization options to support non-standard requirements.
• Provides a multi-stage policy engine to control media and signaling flows per user / user group / source / destination.
• Supports NAT, NAT traversal, codec interworking, and media policy enforcement.
• Delivers carrier-class scalability, performance and high availability – maintaining active calls over failover and in-service upgrade of signaling and media components.
• Scales to hundreds of thousands of concurrent calls and millions of BHCAs with integrated and distributed deployment models, including optimized multi-core and multi-processor support.

Solution Elements

The Metaswitch Session Border Controller solution for IMS is based on the following elements.

• DC-SBC is a fully portable source-code Session Border Controller solution for equipment vendors.
• DC-SIP is a robust, high function, flexible, portable Session Initiation Protocol (SIP) toolkit.
• DC-Diameter is a flexible, portable source code implementation of the Diameter Authorization, Authentication and Accounting (AAA) protocol.
• DC-MGCP/Megaco is a complete, scalable, and fault-tolerant source code implementation of the MGCP and Megaco/H.248 protocols.
• High Availability Framework (HAF) - Metaswitch's architecture for delivering fault tolerance and reduced downtime across the range of network protocols.
• N-BASE - Metaswitch's portable operating environment for network protocols.
• Metaswitch professional services, training, and support directly from the Metaswitch engineering organization.

---

[1] "Enterprise SBC Market Outlook", Infonetics Research, July 2010