一种基于P2P-SIP的可管理和可运维VoIP系统架构

An Administrable and Manageable P2P-SIP Based VoIP System

基于SIP的VoIP系统由于其客户端/服务器的服务架构,在用户规模增大时会引发其固有的单点失效和性能瓶颈问题.P2P和SIP融合的VoIP系统具有良好的扩展性和容错能力,但是现有系统并不能满足可管理和可运维的要求.从运营商的角度考虑,提出了一种基于P2P-SIP的可管理、可运维的VoIP系统架构AMAP.在AMAP系统中,由少量部署的服务器按照DHT协议组成服务覆盖网络.服务覆盖网络使用扩展的SIP信令来维护,为用户代理的注册和会话建立、系统的管理和运维等服务提供支持,可有效地与现有VoIP系统兼容.AMAP系统借助备份和缓存技术提高容错能力,缓解服务热点问题.设计了分布式元数据收集和分发算法,满足了运维信息收集和管理策略下达的需求,对比分析了系统的维护开销,结果表明与现有基于P2P-SIP的VoIP系统相比,AMAP系统减少约80%的开销.详细分析了AMAP系统的功能组成和所涉及的关键技术,并实现和测试了原型系统.

SIP-based VolP systems use C/S architecture, which brings two intrinsic issues when the user number grows to a large scale, namely single point of failure and performance bottleneck problems. The systems based on P2P-SIP are scalable and fault-tolerant. However, existing systems cannot meet the administrable and maintainable requirements from the service providers. The authors propose an administrable and manageable VoIP system based on P2P-SIP, called AMAP. In an AMAP system, a number of servers, deployed by service providers, form a DHT-based service overlay network, which provides services for the user agents, such as registration, session initialization, etc. The AMAP system leverages extended SIP messages for the overlay maintenance and, thus, is compatible with traditional SiP-based VolP systems. To further improve the fault tolerance and relieve the hot spot problem, the AMAP system replicates and caches the user information on the service overlay. A distributed meta-data aggregation and dissemination algorithm is proposed to support the management. This algorithm leverages the tree structures which are implicitly defined on the service overlay based on DHT nodes＇ finger table. The analysis results show that, compared with existing VoIP systems based on P2P-SIP, the AMAP system reduces the maintenance overhead by 80 %. A prototype has been implemented and some functional tests have been performed.