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1 通信网络与交换 1

2 7 软交换与 SDN 网络软交换网络 SDN 网络 2

3 7.1 软交换网络 3

4 下一代网络 (NGN) 的背景当前电信业务发展迅猛, 以互联网为代表的新技术正在改变着传统电信的概念和体系推动下一代网络发展的因素主要包括两个方面 : 基础技术的迅猛发展, 芯片系统业务组成的飞速变化, 新业务层出不穷下一代网络的概念可以有两种定义广义的 : 不同于现有互联网技术的新型网络技术狭义的 : 以软交换 (Softswitch) 设备为控制核心, 能够实现语音数据和多媒体业务的开放的分层体系结构

5 软交换 (Softswitch) 的概念传统的电路交换机将传送硬件呼叫控制和交换以及业务和应用功能结合到单个昂贵的交换机设备中, 是一种垂直集成的封闭的和但厂家专用的系统结构传统的电路交换机的系统结构造成了新业务的开发也是以专有设备和专有软件为载体, 导致开发成本高周期长, 无法适应快速发展的市场和多样化的用户需求软交换将传输呼叫控制和业务控制这三个功能之间的接口打开, 采用开发的接口和通用的协议, 构成一个灵活的系统结构, 使业务提供这能够灵活选择最佳和最经济的组合来构建网络

6 电路交换和软交换的对比 Circuit-Switched Soft-Switched P R O P R I E T A R Y Services & Applications Call Control & Switching Transport Hardware Services, Applications & Features (Management, Provisioning and Back Office) Open Protocols APIs Softswitch Call Control Open Protocols APIs Transport Hardware 所有解决方案由单一厂家提供, 并封装在一个设备中 : software, hardware and applications 用户和厂商之间形成了僵化的绑定, 无法进行高效的创新, 运维成本也较高所有解决方案由多个厂商依据开放的接口提供客户可以自由选择最佳的一流的产品来构建自己的网络, 开放标准实现创新, 降低成本

7 为何要引入软交换? 高性价比 Revenue Cost Packet New revenue streams Improved competitive position Lower port costs Lower operating costs Space and power savings Transport Efficiency Increased development productivity Converged Services Demand creation Traditional Packet Traditional Higher Services Margin Operational Saving 基于分组交换的体系具有更好的性价比! Time

8 软交换的体系结构 Network Management Server Softswitch Application Server Services PSTN, GSM, ATM,... Multiservice Access IP network Media Gateway Transport

9 软交换体系所提供的新契机 PC Application Server Web Collaboration PDA Mobile Phone POTS Converged Service Portal JAIN Parlay JTAPI OSA VXML Service Management Environment Gaming Virtual Reality Multimedia Apps IP Appliance Access Media Communication Server MMS SMS H.323 SIP PRI M-Commerce 3 rd Party Application Enabler for vendor independence, third party service creation

10 软交换交换机的功能模块 Service & Application Plane Management Plane Application/Feature Server (SCP, Service Logic, LDAP Server) IN/AIN Subscriber & Service Provisioning, Network Management, Operation Support, Billing Support Application Signaling (SIP) Media Server Open APIs & Protocols (JAIN, Parlay, XML, SIP) Call Control & Signaling Plane Call Agent, MGC, Softswitch, GK Signaling (MGCP, H.248, SIP) Transport Plane IP Transport Domain: IP Backbone, Routers, Switches, BGs QoS Mechanism (RSVP, Diffserve, MPLS...), MS (Bearer Portion) Interworking Domain: TG (MG), SG, Interworking Gateway SIP-T; H.323 Inter-Network Switch PSTN/SS7/ATM Networks other VoIP Networks Non-IP Access Domain: Wireline Access (AG, Access Proxies) Mobile Access (RAN AG) Broadband Access (IADs, MTAs) IP Phones (H.323, SIP, MGCP,...), IP Terminals, IP PBX Non-IP Terminals/ Mobile Networks

11 关于软交换的 ITU-T NGN architecture (Y.1001) 标准 Softswitch includes MGC, SG, Call Agent Media Gateway is protocol converter Media Gateway Controller is master controller of a media gateway Intelligent Database - Network directory, Billing, Call records H.323/SIP/SIP-T/ SIGTRAN IP Network IW Functions ID/MGC. ID/SG. MGC/MGC. RTP Packet Flow (Voice/Data/MM) Intelligent Database (ID). Signaling Gateway (SG) SG/MGC. MG Controller (MGC) MGC/MG.. Media Gateway. (MG) PSTN/ISDN API Parlay/OSA/LDAP. CC7 ISUP (MTP) MGCP/Megaco(H.248) TDM Flow (Voice)

12 基于软交换的 NGN 体系结构 Application Server IB AAA Network Manager SG Softswitch Switch SS7 STP Softswitch SG Switch SS7 STP PSTN/ISDN MGC PSTN/ISDN Media Gateway Media Gateway Gatekeeper/ Proxy Server Core IP Network (QoS)

13 软定义构建 NGN 网络的关键功能模块 Media Gateway - protocol converter Media Gateway Controller - master controller of a media gateway Softswitch =MGC+SG Signaling Gateway Application Server Information Database (ID) - Network directory, Billing, Call records, Authentication, authorization, and accounting (AAA) Network Manager Operation, Administration, Management (OAM); provides network elements management from a centralized web interface

14 各功能模块相互之间的关系 Application Server IB AAA SOFTSWITCH Signaling Gateway Media Gateway Controller Gatekeeper Network Manager АDSL POTS ISDN PRI V5.x (VoIP) Multiservice Access Multiplexer Media Gateway

15 Media Gateway Media gateway (MG) protocol converter between different types of networks (Example MG between circuit-switched voice network - TDM flows, and the IP network - RTP packet flows. The media gateway (MG) terminates IP and circuitswitched traffic. MGs relay voice, fax, modem and ISDN data traffic over the IP network using Quality of Service enabled IP technology.

16 Softswitch Signaling Gateway Signaling Gateway (SG) offers a consolidated signaling interface for the NGN platform. Media Gateway Controller MGC acts as the master controller of a media gateway Supervises terminals attached to a network Provides a registration of new terminals

17 Application Server Application Server (AS) consists a number of modular application building blocks The modular design of the next generation communications platform makes it easy to deploy enhanced services such as unified communications solutions, multimedia messaging services, and presence & availability management applications.

18 Application Server Application Server generates application documents (VoiceXML pages) in response to requests from the Media Gateway via the internal Ethernet network. The application server leverages a web application infrastructure to interface with data stores (messages stores, user profile databases, content servers) to generate documents (e.g., VoiceXML pages). AS provide interoperability between applications like WAP, HTML, and voice allowing the end user to simultaneously input voice command and receive presentation via WAP or HTML.

19 Authentication, Authorization, Accounting (AAA) Authentication, Authorization, Accounting (AAA) is a term for a framework for intelligently controlling access to computer resources, enforcing policies, auditing usage, and providing the information necessary to bill for services As the first process, authentication provides a way of identifying a user, typically by having the user enter a valid user name and valid password before access is granted. The AAA server compares a user's authentication credentials with other user credentials stored in a database. If the credentials match, the user is granted access to the network. If the credentials are at variance, authentication fails and network access is denied.

20 Authentication, Authorization, Accounting (AAA) Following authentication, a user must gain authorization for doing certain tasks. The authorization process determines whether the user has the authority to issue commands. The authorization is the process of enforcing policies: determining what types or qualities of activities, resources, or services a user is permitted. Usually, authorization occurs within the context of authentication. Once you have authenticated a user, they may be authorized for different types of access or activity.

21 Authentication, Authorization, Accounting (AAA) The final term in the AAA framework is accounting, which measures the resources a user consumes during access. This can include the amount of system time or the amount of data a user has sent and/or received during a session. Accounting is carried out by logging of session statistics and usage information and is used for authorization control, billing, trend analysis, resource utilization, and capacity planning activities. Authentication, authorization, and accounting services are often provided by a dedicated AAA server, a program that performs these functions. A current standard by which network access servers interface with the AAA server is the Remote Authentication Dial-In User Service (RADIUS).

22 RADIUS Remote Authentication Dial-In User Service (RADIUS) is a client/server protocol and software that enables remote access servers to communicate with a central server to authenticate dial-in users and authorize their access to the requested system or service. RADIUS allows a company to maintain user profiles in a central database that all remote servers can share. RADIUS provides better security, allowing a company to set up a policy that can be applied at a single administered network point. Created by Livingston (now owned by Lucent), RADIUS is a de facto industry standard used by a number of network product companies and is a proposed IETF standard.

23 软交换相关的协议 Signaling Protocols H.323 SIP MGCP Megaco/H.248 SIP-T SIGTRAN Mechanisms (QoS, Resource Allocation) MPLS IntServ DiffServ

24 用于支持 VoIP 的协议 : H.323, ITU-T H first call control standard for multimedia networks. It was adopted for VoIP by the ITU in 1996 H.323 is actually a set of recommendations that define how voice, data and video are transmitted over IPbased networks The H.323 recommendation is made up of multiple call control protocols. The audio streams are transacted using the RTP/RTCP In general, H.323 was too broad standard without sufficient efficiency. It also does not guarantee business voice quality

25 用于支持 VoIP 的协议 : SIP - Session Initiation Protocol SIP - standard protocol for initiating an interactive user session that involves multimedia elements such as video, voice, chat, gaming, and virtual reality. Protocol claims to deliver faster call-establishment times. SIP works in the Session layer of IETF/OSI model. SIP can establish multimedia sessions or Internet telephony calls. SIP can also invite participants to unicast or multicast sessions. SIP supports name mapping and redirection services. It makes it possible for users to initiate and receive communications and services from any location, and for networks to identify the users wherever they are.

26 用于支持 VoIP 的协议 : SIP - Session Initiation Protocol SIP client-server protocol, Rq from clients, Rs from servers. Participants are identified by SIP URLs. Requests can be sent through any transport protocol, such as UDP, or TCP. SIP defines the end system to be used for the session, the communication media and media parameters, and the called party's desire to participate in the communication. Once these are assured, SIP establishes call parameters at either end of the communication, and handles call transfer and termination.

27 用于支持 VoIP 的协议 : MGCP/Megaco/H.248 MGCP - Media Gateway Control Protocol, IETF [Telcordia (formerly Bellcore)/Level 3/Cisco] MGCP control protocol that specifically addresses the control of media gateways Megaco/H.248 (IETF, ITU) - standard that combines elements of the MGCP and the H.323, ITU (H.248) The main features of Megaco - scaling (H.323) and multimedia conferencing (MGCP)

28 SIP-T SIP-T (SIP for telephones, previously SIP-BCP-T) is a mechanism that uses SIP to facilitate the interconnection of the PSTN with IP. SIP-T defines SIP functions that map to ISUP interconnection requirements. The protocol is intended to allow traditional IN-type services to be seamlessly handled in the Internet environment. It is essential that SS7 information be available at the points of PSTN interconnection to ensure transparency of features not otherwise supported in SIP. SS7 information should be available in its entirety and without any loss to the SIP network across the PSTN-IP interface.

29 SIGTRAN SIGTRAN (for Signaling Transport) is the standard Telephony Protocol used to transport Signaling System 7 signals over the Internet. SS7 signals consist of special commands for handling a telephone call. Internet telephony uses the IP PS connections to exchange voice, fax, and other forms of information that have traditionally been carried over the dedicated CS connections of the public switched telephone network (PSTN). Calls transmitted over the Internet travel as packets of data on shared lines, avoiding the tolls of PSTN.

30 SIGTRAN A telephone company switch transmits SS7 signals to a SG. The gateway, in turn, converts the signals into SIGTRAN packets for transmission over IP to either the next signaling gateway. The SIGTRAN protocol is actually made up of several components (this is what is sometimes referred to as a protocol stack): standard IP common signaling transport protocol (used to ensure that the data required for signaling is delivered properly), such as the Streaming Control Transport Protocol (SCTP) adaptation protocol that supports "primitives" that are required by another protocol.

31 SCTP TCP transmits data in a single stream (sometimes called a byte stream) and guarantees that data will be delivered in sequence to the application or user at the end point. If there is data loss, or a sequencing error, delivery must be delayed until lost data is retransmitted or an out-of-sequence message is received. SCTP's multi-streaming allows data to be delivered in multiple, independent streams, so that if there is data loss in one stream, delivery will not be affected for the other streams. Because multi-streaming allows data in error-free streams to continue delivery when one stream has an error, the entire transmission is not delayed.

32 NGN as converged networks PSTN Data networks Switch Switch Switch Switch QoS Flexible bandwidth Services SOFTSWITCH Effective transmission Voice services for IP-users VoIP

Master Thesis_專門用來製作目錄.doc

Master Thesis_專門用來製作目錄.doc Introduction All-IP [1-4] All-IP packet switching long delay time, jitter packet loss All-IP Budget-Based QoS End-to-End QoS (real time on demand) 1 1.1 Circuit Switching Packet Switching DWDM IP VoIP