會談邊界控制器
會談邊界控制器（Session Border Controller, SBC），一種NAT穿透的方式。SBC可確保VoIP 安全，又可提供媒體代理伺服器的套件。
SBC架構於IMS網絡之上，可作為IMS網絡的SIP和RTSP的 Proxy Server，所有的SIP與RTSP訊息都會透過SBC來處理，SBC更具備NAT穿透的功能。目前思科與 Kagoor 對會談邊界控制技術有突破性的發展。
功能
SBCs 會維持整個會議狀態並提供以下功能:
- 網絡安全 – 保護網絡以及其他裝置:
- 連結 – 允許不同網域之間的溝通:
- 服務質量 – QoS 的政策是網絡狀態的優先取捨問題. 其功能如下:
- Traffic policing
- Resource allocation
- Rate limiting
- Call admission control
- TOS/DSCP bit setting
- Regulatory – many times the SBC is expected to provide support for regulatory requirements such as:
- emergency calls prioritization and
- lawful interception
- Media services – many of the new generation of SBCs also provide built-in digital signal processors (DSPs) to enable them to offer border-based media control and services such as:
- DTMF 中繼與互連
- 媒體轉碼
- Tones 與 announcements
- 數據與內網傳真
- 支援音訊與影訊
- 統計與傳單資訊 – since all sessions that pass through the edge of the network pass through the SBC, it is a natural point to gather statistics and usage based information on these sessions.
參考書目
- Hautakorpi, J.; Camarillo, G.; Penfield, R.; Hawrylyshen, A.; Bhatia, M.. Requirements from SIP (Session Initiation Protocol) Session Border Control Deployments. IETF. April 2010. RFC 5853.
- Sinnreich, Henry; Johnston, Alan B., Internet Communication Using SIP, Wiley: 180, 2001, ISBN 0-471-77657-2
- Juniper Networks, The Benefits of Router-Integrated Session Border Control (PDF), 2009, （原始內容 (PDF)存檔於2012-11-07）
- Sonus Networks WhitePaper — Performance reality of Session Border Controllers
- Acme Packet White Paper （頁面存檔備份，存於互聯網檔案館） — defines the need for session border controllers for interactive IP services
- AudioCodes White Paper — on Enterprise Session Border Controllers.