【作者】 苟先太；

【导师】 金炜东；

【作者基本信息】 西南交通大学 ， 电气系统控制与信息技术， 2005， 博士

【摘要】 下一代网络NGN(Next Generation Networks)融合传统的PSTN语音网络、计算机网络、移动通信网络。NGN中存在一些复杂的计算任务和通信任务。Multi-agent技术研究通过多个Agent之间的通信、协作、互操作来完成单个Agent很难或无法单独完成的复杂任务。为此,本文讨论如何将多代理技术用于NGN完成一些复杂的通信任务与计算任务。 多媒体通信穿越NAT/Firewall是NGN中一个复杂的通信任务。由于多媒体通信属于集束回话通信(Bundled Session Communications),多媒体通信不能直接穿越NAT/Firewall。如何全面完善地解决这个问题,已成为一个国际性的难题。为此,国际标准组织IETF,以及Cisco、Microsoft、3COM等国际大公司已经给出的一些解决方法。但是,这些方法主要针对一些特定的协议,仅适合于一些特定的应用模式,还不能用于NGN较为全面地解决穿越问题。软交换需要完成信令转换、呼叫控制、业务控制等多种计算,它是NGN中的一个复杂计算任务。 目前,Agent技术主要用来完成对实时性、交互性要求不高的知识交换和知识操作,不太适合于大数据量的信息交换。如何扩展Agent之间的通信能力,让Agent除了支持知识共享,还能支持实时性、交互性强的多层次、多回合的多媒体通信任务,支持大数据量的语音、视频格式的信息交换:以及如何将Agent技术,特别是Multi-agent技术用于NGN,以解决一些复杂的任务,还存在诸多理论问题和技术实现困难,是一个需要深入研究的问题。 本文旨在给出一种新的代理通信语言及其执行模型,通过扩展Agent之间的通信能力,使多代理系统能对实时性、交互性要求高的多层次、多回合的多媒体通信任务提供支持。并将其用于NGN中完成多媒体通信穿越NAT/Firewall问题和软交换计算任务。 本文从以下几个方面进行了研究: (1) 给出支持多媒体通信任务的代理通信语言 ACLMC(Agent Communication Language for Multimedia Communication)的通信原语和语法定义。ACLMC语言通过定义特定交互原语来直接表达多媒体通信任务的交互意图,并能支持实时交互。以ITU-T Q.931作为呼叫基本参考模型,并兼顾ACLMC语言与MoIP(Multimedia Communication over IP)协议之间的映射需要,同时结合KQML和FIPA ACL的两种通信语言基本特性,给出ACLMC原语。除此之外,考虑每次通信任务对呼叫标识、地址、媒体格式等呼叫知识的表达需求,描述了KIF 、KIT两种呼叫知识表达方式。为了保证Agent和周围环境中的实体进行多媒体交互,需要考虑如何使只能理解ACLMC语言的Agent,与只能解析MoIP协议的外部实体之间完成多媒体交互。更多还原

【Abstract】 The next-generation network (NGN), based on IP, will converge all telecom traffic as public switched telephone network (PSTN), wireless networks and computer networks into one. There are many complex computing tasks and communication tasks in NGN. Based on the cooperation, coordination, communication of agents, Multi-agent System (MAS) can be employed to accomplish the complex task that is difficult or even impossible to accomplish for a sole-agent system. Therefore, we mainly discuss how to apply multi-agent technologies to accomplish the complex computing tasks and communication tasks in NGN.At present, agent technologies are mainly employed to accomplish the knowledge sharing and manipulating that does not require high real-time and interactive proceeding. They are not suitable for the switching mass information too. So, how to extend the capability of communication between agents, and to have agents to be able to deal with real-time, interactive, multi-level and multi-round task? How to have agents to be able to deal with switching mass information, especially such as multimedia information? And how to have agent technologies to be employed in NGN to achieve complex its computing task? There are many difficulties in theory and realization to address them. It should be researched in depth.It’s a complex communication task for multimedia communication to traverse NAT/Firewall in NGN. As bundled-session communication, multimedia communication can’t traverse NAT/Firewall directly, which is a global difficult problem for audio and video application to be really deployed in NGN. Although several solutions has been proposed separately by Microsoft, Cisco, 3Com and some international standardization organization, they can’t resolve the problem very well at all by now. Softswitch needs to accomplish signaling switch, call control and service control etc. It is a complex computing task in NGN.This dissertation focuses on proposing a new Agent Communication Language and its executing model to have Multi-agent system to support the multimedia communication task in NGN. Furthermore, we use it to resolve the problem of multimedia communication traversing NAT/Firewall, and design multi-agent based Softswitch.Concretely, the main research works are as follows:(1) This dissertation proposed a new specification of Agent Communication Language for multimedia communication (ACLMC) task. The primitives of ACLMC are designed by referring to ITU-T Q.931, KQML and FIPA ACL. This design is also fully taken account of the message mapping between ACLMC and MoIP protocols such as H.323, SIP etc. The semantic of ACLMC are defined. Compared with KQML, ACLMC can directly express the intention of interaction of agents by providing the interactive primitive. Therefore, it can support the real-time interaction among agents. The communication structure is also presented. Take account of the requirement of agents interacting with periphery entity based on MoIP protocol, the mappings between ACLMC primitive and MoIP protocol, including message mapping, message sequence mapping, media coding format and call addresses mapping, are also presented. The using KIF (Knowledge Interchange Format) as content language of ACLMC is discussed. The way of call knowledge expression and format of knowledge exchange arc also presented.(2) Based on the BDI (Belief Desire> Intention ) agent model, the dissertation defines the interpreting and executing model of ACLMC. As to describe the Belief, Desire and Intention, a new agent (describe) language MC-agentspeak is proposed. Its format and semantic are defined. MC-agentspeak looks an agent as an object composed of a group of static sets and operations that are on behalf of the events, beliefs, plans, intentions, actions goal of agent. The ESA rules are given to plan the actions of agents. The executing model is described by using Operational Semantics of MC-agentspeak.(3) The multi-agent system for multimedia communication traversing NAT/Firewall is designed. Through the communication based on ALCMC among agents, the system converts the bundled session communication into non-bunlded session communication in NAT/Firewall, and non-bunlded session can traversing multi-level NAT/Firewall directly. The theory of this traversing way is also proved. The security and performance of the system are discussed too. The system has better capability than that of the other solutions. It can meet the traversing of all MoIP protocols. It can traverse multi-level NAT/Firewall. Its implementation does not need to update the installed NATs/Firewalls. The experiment verified the design of the system.(4) The multi-agent based Softswitch is presented. The architectureof the system and function model of agents has been designed. The communication method and procedure of interaction has also been discussed. The simulation results verified the thinking of the dissertation.This dissertation proposed the ACLMC language and its interpreting and executing model, which is the fist-step for multi-agent technologies being used in NGN to accomplish those complex multimedia-concered tasks. Besides resolving the two problems of this paper, the ACLMC language can be also used to implement the intelligent, distributed and personalized service control and management in company with mobile agent technologies in the future.更多还原