Softswitch over IP Network LG 전자 디지털네트워크연구소강태익책임연구원 E-mail : tikang@lge.com 1
Contents I. Softswitch 정의 II. 통신망구조 III. Softswitch 망구조 IV. Softswitch Protocol V. Softswitch Model VI. 서비스구조 VII. 발전방향 2
I.Softswitch 정의 다양한 Signaling에대한 Gateway 역할 Media Gateway 및 IP Endpoints 에대한부가서비스제공 각호에적절한 Service Selection 제공 End-to-end Real-time (RTP-based) Connections 제공 가입자, Carrier 근거의 Call Routing 타 Network Element 로의 Call Control 전환 Management functions 정합 ( for provisioning, fault, billing, etc. ) 세션베이스네트워크서비스를제공하기위해 Media 를 Control하는 Session Management System 3
I.Softswitch 정의 Softswitch 장점 Open Architecture, Open Standard 확장성 : Scalability - Growth to many millions of BHCA 신뢰성 : Redundancy - state persistence 호환성 : Interoperability 타 Gateways, 타 Softswitches 서비스생성 : Service Extensibility - Time to market of innovative new services by third parties 4
I.Softswitch 정의 Application Servers SS7 Gateway SS7 Digital Cross Connect SIP CPL Q.931/Q.2931 Softswitch MGCP Cellular Station H.323 IAD with DSL/Cable Modem MEGACO MGCP MGCP - Media Gateway Control Protocol, combo of SGCP and IPDC MEGACO/H.248, evolution of MGCP H.323 - ITU protocol, originally geared toward LAN specs. SIP - Session Initiated Protocol, speaks between user and IP/media gateways SIP Media Gateways 5 LG 전자 강태익
I.Softswitch 정의 Softswitch API Enterprise Server HLR IN-SCP CAMEL SCP Clearing House Script Server PINT server IP-SCP AAA server PARLAY MAP INAP CAMEL OSP XML PINT SigTran RADIUS... Local application module(s) SOFTSWITCH = Connection control module Softswitch API H.323, SIP MGCP Elements of the transport / media layer 6
I.Softswitch 정의 Softswitch API Softswitch Module 과 Softswitch API는독립적인구조 Softswitch API 는 Remote Data/Logic Servers (Application Server) 와 Interaction 이지원. Softswitch API 는 Remote server 정합을위한다양한 Protocol이지원되어야한다. Softswitch API 는모든 Intelligence (Numbering plan, Billing Schemes, Call Routing, User Authentication, Bandwidth Allocation 등 ) 지원. Softswitch API 는 Establishment of connections, Notification of events, Termination of connections 등을지원. Softswitch API 는 Download/Installation of Scripts (stored procedures) 7
II. 통신망구조 Conventional Architecture Softswitch Architecture Services Billing System Mgmt System Services SCP SS7 Network TDM Switch Controller SS7 Network MGCP/Megaco Softswitch MGCP/Megaco T D M Time Slot Interchange T D M T D M Packet Data Backbone T D M Line Card Trunk Card Media Gateway Media Gateway 8
II. 통신망구조 Circuit-switch vs. Softswitch Open Architecture, Open Standard, Open API - Service(Application), Call Control, Transport 분리 각계층별로다양한제품및 Vendors 존재 - 사업자의 Third Parties 활용이가능 확장성과운용비용등 Cost Reduction Time to Market Multimedai 서비스제공 (Voice, Video, Data Convergence ) 기존서비스및새롭고향상된서비스제공 9
II. 통신망구조 Circuit-switch vs. Softswitch 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 10 Solutions come from a single vendor that supplied everything in one proprietary box: software, hardware and applications Customers were locked-in to their vendor no room for innovation, expensive to implement and maintain Solutions can come from multiple vendors, at all levels who supply open standards-based products Customers are free to choose best-in-class products to build their network. Open standards enable innovation and reduce costs
III. Softswitch 망구조 SS7 Network PSTN SIP/BICC Class 4 Softswitch SIP App Server Softswitch Class 4 Class 5 MGCP/H.248 Class 5 IP/ATM Network Media Gateway Media Gateway Media Server 11
III. Softswitch 망 구조 SoftSwitch Legacy Network Signaling/Service Network Service Layer Legacy Network Media Control Layer Network Independent Services Media Gateway Media Layer Access and Transport Layer Enterprise Customers 12 LG 전자 강태익
IV. Softswitch Protocol H.323, SIP는 IP 기반, IETF 에서표준화주도, VoIP 제공 BICC는 AMT기반, ITU에서표준화주도, VoATM 제공 13
IV. Softswitch Protocol 14
V. Softswitch Model APPLICATION SERVER SIP MEDIA SERVER SIP SOFTSWITCH RTP SOFTSWITCH RTP SIGNALING GATEWAY MEDIA GATEWAY RTP MEDIA GATEWAY SIGNALING GATEWAY SS7 PSTN PSTN SS7 15
V. Softswitch Model Softswitch - Connection Control, Translations, Routing, Gateway Management, Call Control, Bandwidth Management, Signaling, Provisioning, Security, 그리고 Call Detail Record Generation 을제공 - 다음과같은기능을처리한다 (SIP based). User Agent Proxy Server for SIP for SIP communication Redirect Server Location Server / Register 16
V. Softswitch Model Softswitch APPLICATION SERVER APPLICATION SERVER APPLICATION SERVER INVITE 3XX REDIRECT INVITE 200 OK BYE/ALSO 200 OK INVITE 200 OK INVITE 200 OK ACK ACK SOFTSWITCH SOFTSWITCH SOFTSWITCH SOFTSWITCH REDIRECTION ACCEPT AND TRANSFER PROXY Redirection : Routing Type Services Accept and Transfer : Card and IVR Type Services Proxy : Accounting and Monitoring Type Services 17
V. Softswitch Model Application Server - Softswitch 와 Signaling interface 를다루는 Enhanced Services 의 수행과관리를위한 Platform. - 서비스생성및구현을위한 API 제공 - Application Server 다음과같은요소와는분리되어야한다.. Network 구조. Signaling Protocol (e.g. SS7, ISDN, CAS, H.323, SIP). Media Gateway Control Protocol (e.g. IPDC, MGCP, H.248 ) 18
V. Softswitch Model Media Server - Media Gateway 와 Bearer Interface 를다루는특수 Media Resources (IVR, Conferencing, FAX, ASR, TTS 등 ) 를제공하는 Platform. Softswitch SIP Application Server JTAPI JAIN PARLAY AIN/IN Media Gateway RTP Media Server FAX IVR CONF TTS 19
V. Softswitch Model Media Server Slave Device Simple, Plug-and-Play Service Building Blocks, not Service Logic No Billing, No Complex OSS Interfaces No Call Control or Signaling 20
V. Softswitch Model Signaling Gateway - ISUP과 TCAP 같은프로토콜을포함하여 SS7 Signaling Network과 Packet Network 사이의변환을제공하는데, 흔히 Softswitch에통합된다 Media Gateway - Voice Compression, Fax Relay, Echo Cancellation, 그리고 Digit Detection을포함하는 Circuit-Switched Resources와 Packet Networks(IP, ATM) 사이의변환을제공 21
VI. 서비스구조 1. Softswitch Control SCP SS7 Terminate SS7 A/F-links SS7/IP to other devices SS7 Gateway Softswitch Provisioning Services Routing Call Control Circuit Packet Gateway Switch Convert between circuit and packet Echo cancellation Audio processing 22
VI. 서비스구조 1. Softswitch Control Softswitch IP Phone H.323/SIP/MGCP /Megaco MGCP/Megaco MGCP/Megaco RTP PSTN Phone RTP Media Gateway Media Server 23
VI. 서비스구조 2. Application Server Control SCP SS7 SS7 Gateway Softswitch Circuit Gateway Switch Packet Open AS AS Application Servers AS 24
VI. 서비스구조 2. Application Server Control Softswitch Application Server H.323/SIP IP Phone H.323/SIP/MGCP /Megaco MGCP/Megaco MGCP/Megaco RTP PSTN Phone RTP Media Gateway Media Server 25
VII. 발전방향 Carrier 요구사항 Take advantage at each layer Each layer brings vendor opportunities Vendor solutions can plug and play Class 5 Features IP Centrex Capabilities to deliver integrated call center services Softswitch Interoperability Service Creation Capabilities APIs for Carriers Portals for End-users 26
VII. 발전방향 발전방향및전망 다양한 Protocols 지원 ( MGCP, MEGACO, SIP, SS7, CPL, H.323, Q.931/Q.2931, DiffServ, RSVP, RTP, RCP, MPLS, 802.1p, etc.) 다양한 Standards Bodies 와긴밀한공조 (e.g. ITU, IETF, FRF, ATM Forum, IEEE, etc.) 많은사업자에의한구현 Evolving Architecture 에대한호환성유지 Under Legacy Regulatory Conditions (e.g. tariffs, co-location, certifications, etc.) In a Global Marketplace Carrier 요구사항을충족하여야한다. All fully interoperable with the TDM-based PSTN 27