1、NGN承載網(wǎng)體系結(jié)構(gòu)探索,華為技術(shù)有限公司 戰(zhàn)略與Marketing未來(lái)網(wǎng)絡(luò)研究部 李國(guó)平,2,一、對(duì)NGN承載網(wǎng)體系結(jié)構(gòu)的思考 二、NGN承載網(wǎng)解決方案（IPTN） 三、國(guó)際標(biāo)準(zhǔn)化進(jìn)展,3,第一部分 對(duì)NGN承載網(wǎng)體系結(jié)構(gòu)的思考,4,網(wǎng)絡(luò)控制架構(gòu)的演變,Traditional Network Control Model,IN, AIN, & Camel,Switch Fabric,Call Control,Bearer Path Control,IN Services,Analog Circuit Wireless,IP/MPLS Domain,Session Control Plane D

2、omain (Softswitch,CSCF),App Servers,App Servers,App Servers,SIP,Diameter,Analog Circuit Wireless,SIP Endpoints,NGN Network Control Model,基于設(shè)備的解決方案,基于網(wǎng)絡(luò)的解決方案,不成熟，發(fā)展中,5,對(duì)通信網(wǎng)控制體系的分類,通信網(wǎng)控制三對(duì)象：路由、鏈路資源（Link Resource）、會(huì)話（Session） 路由的控制模式：靜態(tài)生成、動(dòng)態(tài)生成；分布路由控制、集中式路由模式 鏈路資源的控制模式有：分布式、集中式；動(dòng)態(tài)資源控制、靜態(tài)資源控制 Internet網(wǎng)絡(luò)只

3、控制路由，所以簡(jiǎn)單 PSTN、ASON同時(shí)在一個(gè)設(shè)備上實(shí)現(xiàn)對(duì)三個(gè)對(duì)象的控制 SDH網(wǎng)對(duì)三個(gè)對(duì)象的控制全由網(wǎng)管實(shí)現(xiàn) NGN網(wǎng)絡(luò)將對(duì)這三個(gè)對(duì)象的控制分布不同的設(shè)備上實(shí)現(xiàn),6,對(duì)NGN“承載與控制分離”的置疑,軟交換和承載層路由器不發(fā)生任何聯(lián)系行得通嗎？ 承載與控制分離是要付出代價(jià)的 承載與控制不能絕對(duì)的分離 可能造成軟交換計(jì)費(fèi)精度不及PSTN，很難達(dá)到秒級(jí)計(jì)費(fèi),軟交換和承載網(wǎng)一定要以某種方式發(fā)生聯(lián)系！,IP/MPLS Domain,Session Control Plane Domain (Softswitch, CSCF),7,3GPP對(duì)“承載與控制分離”的考慮,在R5/R6中引入PDF功能實(shí)體

4、，將控制層和承載層有機(jī)的聯(lián)系起來(lái),“這就需要IMS（控制平面）和GPRS網(wǎng)絡(luò)（用戶平面）之間的溝通。Go參考點(diǎn)最初就是出于這個(gè)目的被定義的?！?Nokia專家書,8,ITU-T對(duì)“承載與控制分離”的考慮,There is interaction between control plane in service layer and control plane in transport layer. This interaction includes request/modification acceptance/rejection/release/report for resources of

5、service for session-based or non-session based services.,9,為何IP網(wǎng)絡(luò)不能滿足電信的需求？（一）,如果不考慮復(fù)雜的商業(yè)運(yùn)營(yíng)，目前的IP網(wǎng)絡(luò)提供的隨時(shí)隨地的連通性基本能滿足人們的溝通需求 一旦考慮復(fù)雜的商業(yè)應(yīng)用環(huán)境，Raw IP網(wǎng)絡(luò)的很多問(wèn)題就暴露出來(lái)了 計(jì)費(fèi)問(wèn)題（商業(yè)網(wǎng)絡(luò)的基石）： 用戶身份如何識(shí)別？企業(yè)網(wǎng)無(wú)需BRAS，電信網(wǎng)需要BRAS 提供差異化業(yè)務(wù)問(wèn)題（QoS）： Internet無(wú)法按質(zhì)論價(jià)；為提升網(wǎng)絡(luò)價(jià)值，針對(duì)不同客戶提供不同等級(jí)的服務(wù)？ 安全問(wèn)題：(可用性) 提供商業(yè)服務(wù)的網(wǎng)絡(luò)老被攻癱能行嗎？IP網(wǎng)絡(luò)固有設(shè)計(jì)缺陷,Raw

6、IP和電信網(wǎng)在觀念上存在巨大差異,10,為何IP網(wǎng)絡(luò)不能滿足電信的需求？（二）,Internet的設(shè)計(jì)思想是智能分散在終端，網(wǎng)絡(luò)是傻瓜，網(wǎng)絡(luò)不了解用戶業(yè)務(wù)的質(zhì)量要求 路由器的網(wǎng)絡(luò)層智能太少，路由器計(jì)算出來(lái)的路由可能是不可用的，路由器只根據(jù)局部信息計(jì)算路由 現(xiàn)在因特網(wǎng)是無(wú)連接的，如果下一代網(wǎng)是基于IP的是無(wú)連接的，無(wú)連接歸根到底是解決不了QoS的，只能有限范圍解決 NGN將采用Internet的技術(shù)（IP或IP友好的傳送技術(shù)）但不是其機(jī)理，即不再讓網(wǎng)絡(luò)作為傻瓜把復(fù)雜功能推給終端，在資源分配和業(yè)務(wù)傳遞方面網(wǎng)絡(luò)必須是主動(dòng)的和有智能的，不能象Internet那樣靠終端來(lái)適應(yīng),11,BT對(duì)IP技術(shù)的深刻

7、反思（一）,下一代網(wǎng)選擇何種技術(shù)架構(gòu)？,Convergence does not mean: Only 1 IP layer controlling all services (e.g. GMPLS) Connectionless (CNLS) only (e.g. Internet). Connection Oriented (CO) only (e.g. ATM). Technology Service,Internet,Frame Relay,ATM,SDH,Converged multi-Service network,12,BT對(duì)IP技術(shù)的深刻反思（二）,三種網(wǎng)絡(luò)模式,Functio

8、nal Convergence,There are 3 networking modes that all technologies map into: CNLS e.g. IP, Ethernet. CO Packet Switch e.g. FR, ATM, MPLS. CO Circuit Switch (for bulk transport) e.g. SDH, PDH, OTN. We need all 3 modes to deliver all the services required by our customers: It is not a VHS v. Betamax p

9、opularity competition.,CNLS,CO-PS,CO-CS,13,BT對(duì)IP技術(shù)的深刻反思（三）,為何需要三種網(wǎng)絡(luò)模式？,CNLS delivers the Internet. CO-CS delivers the raw bandwidth circuits. Noting that: The size of the circuits we want to switch are getting larger. Well cease to circuit switch the smaller bandwidths ( VC4). Packet switching a flo

10、w that is large enough to be circuit switched is expensive. CO-PS fits the role for customers wanting the strong SLGs of circuits but wanting VC4 worth of bandwidth.,Why do we need 3 modes?,14,BT對(duì)IP技術(shù)的深刻反思（四）,Raw IP能不能解決問(wèn)題？,The infinite bandwidth all the time solution! With some bandwidth squeezing

11、mechanisms to compensate. Besides misses the point of what a connection is.,Use lots of bandwidth,Try to save a little,Use slightly less than lots of bandwidth,Could CNLS Do It All?,15,BT對(duì)IP技術(shù)的深刻反思（五）,面向連接對(duì)電信網(wǎng)的重要性,The essence of a carriers service. It is what we manage to provide customer isolation

12、& identification. Transparent transport between end points of the network. The basis of performance guarantees on the probability of obtaining reliable transparent transport of information. The basis of end to end monitoring of the integrity of the transparent transport of the information.,Connectio

13、ns,A Connection Is:,16,BT對(duì)IP技術(shù)的深刻反思（六）,下一代網(wǎng)的技術(shù)架構(gòu),The “Architecturally Good” IP Friendly Label stacking Variable length frames Y.1711 OAM,MPLS for CO-PS infrastructure,17,BT對(duì)IP技術(shù)的深刻反思（七）,QoS如何解決？,We need the capability to have both a packet view, and the packets parent connection view, to fully addre

14、ss the QoS, fairness, meaningfulness, charging problem across all types of service. There is a need for both CO-PS & CNLS network operation in order to support both CO & CNLS services The network needs to be able to deliver both to customers as a seamless services carried over a common network capab

15、le of both CO-PS & CNLS network operation CO-PS operation requires bandwidth allocation, routing and admission control to be coordinated to ensure that SLAs are met and to achieve efficient use of bandwidth,Whats the answer to QoS?,電信網(wǎng)需要的不是基于包的QoS機(jī)制，而是基于連接的QoS機(jī)制,18,BT對(duì)IP技術(shù)的深刻反思（八）,帶外控制是解決安全的唯一出路,Pho

16、ne freakers return if we stick to todays IP architecture! The PSTN learnt the control plane had to be out of band to be secure. The Cisco “packets of death” demonstrated the weakness of todays IP architecture with the control & user planes congruent. Current fixes of layering security on router oper

17、ating systems to protect routers control & management planes are expensive & unsafe. OOB control & management planes are essential for security. Does not require significant protocol modification. Requires change of architecture thinking. Lower cost & safer.,Out of band management & control data pla

18、ne must be independent of all the elements being managed & controlled.,SecurityThere have been more attacks in the last six months than there has been in the last 10 years, Eslambolchi, AT&T.,19,NGN對(duì)IP承載網(wǎng)的需求總結(jié),IP承載網(wǎng)必須以某種方式和業(yè)務(wù)層發(fā)生聯(lián)系 IP承載網(wǎng)必須同時(shí)支持COPS和CNLS兩種網(wǎng)絡(luò)模式 基于COPS網(wǎng)絡(luò)模式構(gòu)成的承載子網(wǎng)必須有QoS、安全性、可靠性保證 MPLS及其OA

19、M技術(shù)在COPS網(wǎng)絡(luò)模式中將發(fā)揮重要作用,20,第二部分 NGN承載網(wǎng)解決方案,21,NGN承載網(wǎng)總體架構(gòu),22,骨干網(wǎng)部分的總體架構(gòu),23,骨干網(wǎng)方案的主要特點(diǎn),采用MPLS技術(shù)將IP物理網(wǎng)絡(luò)劃分為COPS和CNLS兩個(gè)子網(wǎng)，COPS子網(wǎng)承載有QoS保證的業(yè)務(wù)，CNLS承載Internet業(yè)務(wù) COPS子網(wǎng)采用MPLS轉(zhuǎn)發(fā)技術(shù)，同時(shí)采用帶外控制技術(shù)嚴(yán)格保證電信業(yè)務(wù)的QoS 采用LSP逐段建立和分域分層技術(shù)，保證了方案的可擴(kuò)展性 不改動(dòng)骨干路由器，可同時(shí)承載Internet業(yè)務(wù)和電信業(yè)務(wù),24,骨干網(wǎng)QoS選路過(guò)程,25,業(yè)務(wù)識(shí)別及數(shù)據(jù)平面安全解決方法,端局路由器,輸入 處理,流分類表,業(yè)務(wù)流

20、,RM,IP電信網(wǎng),查流分 類表,MPLS,漏桶算法,輸出 處理,其他 處理,路由 轉(zhuǎn)發(fā),命中 否？,其他 處理,Internet網(wǎng),IP1,IP2,每個(gè)流分類表項(xiàng)代表的是一個(gè)連接 查流分類表的過(guò)程實(shí)際上是判別數(shù)據(jù)包屬于哪個(gè)連接的過(guò)程,業(yè)務(wù)識(shí)別完全受網(wǎng)絡(luò)控制,IP端局功能框圖,26,接入網(wǎng)總體方案,27,第三部分 國(guó)際標(biāo)準(zhǔn)化進(jìn)展,28,TISPAN：RACS Subsystem,29,TISPAN: RACS Functional Architecture,30,華為在TISPAN RACS的活動(dòng),參加2004年9月13日9月17日會(huì)議，提交文稿9篇，“WI for Bearer Contro

21、l Requirements” 的建議得到大會(huì)批準(zhǔn)，鄒婷當(dāng)選為該Work Item的Rapporteur,31,ITU-T SG13: Y.1291,Approved in 05/2004: “An architectural framework for support of Quality of Service (QoS) in packet networks” Describes six QoS approaches: IntServ,DiffServ,MPLS, IPCablecom Dynamic QoS,Centralized and Path-decoupled Resource

22、Control, Priority Promotion Scheme Centralized and Path-decoupled Resource Control: provided by Huawei and China Telecom,32,ITU-T SG13: RACS (1),In drafting stage: “Functional Requirements and Architecture for Resource and Admission Control in Next Generation Networks” Co-Rapporteur and Editor: 劉恩惠 核心思想來(lái)自華為,33,ITU-T SG13: RACS (2),Core RACF,Access RACF,Resource Mediation,Application Functions,CPN,Network Access Attachment Functions,Other networks,IBCF,I-BGF,M-PDF,ENF,A-BGF,I-PDF,C-TRCF,A-TRCF,I d,G q,Go,G3,I1,SCPF,C3,X