1、 International Telecommunication Union ITU-T Series YTELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Supplement 11(01/2010) SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS ITU-T Y.2600 series Supplement on scenarios for independent scalable control
2、 plane (iSCP) in future packet-based networks (FPBN) ITU-T Y-series Recommendations Supplement 11 ITU-T Y-SERIES RECOMMENDATIONS GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS GLOBAL INFORMATION INFRASTRUCTURE General Y.100Y.199 Services, applications and m
3、iddleware Y.200Y.299 Network aspects Y.300Y.399 Interfaces and protocols Y.400Y.499 Numbering, addressing and naming Y.500Y.599 Operation, administration and maintenance Y.600Y.699 Security Y.700Y.799 Performances Y.800Y.899 INTERNET PROTOCOL ASPECTS General Y.1000Y.1099 Services and applications Y.
4、1100Y.1199 Architecture, access, network capabilities and resource management Y.1200Y.1299 Transport Y.1300Y.1399 Interworking Y.1400Y.1499 Quality of service and network performance Y.1500Y.1599 Signalling Y.1600Y.1699 Operation, administration and maintenance Y.1700Y.1799 Charging Y.1800Y.1899 IPT
5、V over NGN Y.1900Y.1999 NEXT GENERATION NETWORKS Frameworks and functional architecture models Y.2000Y.2099 Quality of Service and performance Y.2100Y.2199 Service aspects: Service capabilities and service architecture Y.2200Y.2249 Service aspects: Interoperability of services and networks in NGN Y.
6、2250Y.2299 Numbering, naming and addressing Y.2300Y.2399 Network management Y.2400Y.2499 Network control architectures and protocols Y.2500Y.2599 Future networks Y.2600Y.2699Security Y.2700Y.2799 Generalized mobility Y.2800Y.2899 Carrier grade open environment Y.2900Y.2999 For further details, pleas
7、e refer to the list of ITU-T Recommendations. Y series Supplement 11 (01/2010) i Supplement 11 to ITU-T Y-series Recommendations ITU-T Y.2600 series Supplement on scenarios for independent scalable control plane (iSCP) in future packet-based networks (FPBN) Summary Supplement 11 to ITU-T Y-series Re
8、commendations describes application scenarios provided by an independent scalable control plane (iSCP) which separates the control plane from the data plane in the future packet-based networks. This supplement can be used for providing guidance for defining iSCP requirements. History Edition Recomme
9、ndation Approval Study Group 1.0 ITU-T Y Suppl. 11 2010-01-29 13 Keywords Control plane, data plane, FPBN, scenarios, separation. ii Y series Supplement 11 (01/2010) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications,
10、information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on
11、a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid dow
12、n in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this publication, the expression “Administration“ is used for conciseness to indicate both a telecommunication adm
13、inistration and a recognized operating agency. Compliance with this publication is voluntary. However, the publication may contain certain mandatory provisions (to ensure e.g., interoperability or applicability) and compliance with the publication is achieved when all of these mandatory provisions a
14、re met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the publication is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the poss
15、ibility that the practice or implementation of this publication may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the pub
16、lication development process. As of the date of approval of this publication, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this publication. However, implementers are cautioned that this may not represent the latest information and ar
17、e therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2010 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Y series Supplement 11 (01/2010) iii CONTENTS Page 1 Scope
18、 1 2 References. 1 3 Terms and definitions . 1 4 Abbreviations and acronyms 2 5 Conventions 2 6 Issues with current IP networks 2 7 Overview of the iSCP . 3 8 Application scenarios 4 8.1 Cluster router scenarios 4 8.2 CE/SCEs cooperation scenarios . 5 8.3 Configuration scenarios 7 8.4 Forwarding and
19、 processing scenarios . 9 Y series Supplement 11 (01/2010) 1 Supplement 11 to ITU-T Y-series Recommendations ITU-T Y.2600 series Supplement on scenarios for independent scalable control plane (iSCP) in future packet-based networks (FPBN) 1 Scope This supplement describes the issues with current Inte
20、rnet Protocol (IP) networks and provides application scenarios and improvements provided by an independent scalable control plane (iSCP) which separates the control plane from the data plane in the future packet-based networks as described in ITU-T Y.2601. 2 References ITU-T Y.2601 Recommendation IT
21、U-T Y.2601 (2006), Fundamental characteristics and requirements of future packet based networks. IETF RFC 3654 IETF RFC 3654 (2003), Requirements for Separation of IP Control and Forwarding. IETF RFC 3746 IETF RFC 3746 (2004), Forwarding and Control Element Separation (ForCES) Framework. 3 Terms and
22、 definitions This supplement defines the following terms: 3.1 control element (CE): A control element is an entity which makes routing computation and decisions on Internet Protocol/multi-protocol label switching (IP/MPLS) forwarding table for one or multiple forwarding elements (FEs) based on a net
23、work-wide view according to network-level optimization and consistency objectives. 3.2 forwarding element (FE): A forwarding element (FE) is an entity which forwards the user data traffic according to the routing decisions of the CE(s). 3.3 management element (ME): A management element is an entity
24、which manages control elements (CEs), service control elements (SCEs), forwarding elements (FEs) and service processing elements (SPEs), and partitions them into multiple re-constructible virtual network elements (VNEs). 3.4 service control element (SCE): A service control element is an entity which
25、 makes network service decisions on security, network address translation (NAT) and other layer 4 to 7 services for one or multiple service processing elements (SPEs) at the network level. 3.5 service processing element (SPE): A service processing element (SPE) is an entity which handles the user da
26、ta traffic according to the network service decisions of the service control element(s) (SCEs), including deep packet inspection (DPI), network address translation (NAT), firewall, encryption/decryption, protocol conversion, monitoring, content processing and application acceleration, etc. 3.6 virtu
27、al network element (VNE): A virtual network element is a virtual heterogeneous cluster router consisting of multiple control elements (CEs), service control elements (SCEs), forwarding elements (FEs) and service processing elements (SPEs), which supports the appearance of a single functional network
28、 entity with high throughput for a given application service traffic (video, voice or data). 2 Y series Supplement 11 (01/2010) 4 Abbreviations and acronyms This supplement uses the following abbreviations and acronyms: CE Control Element DPI Deep Packet Inspection FE Forwarding Element FIB Forwardi
29、ng Information Base IP Internet Protocol iSCP independent Scalable Control Plane ME Management Element MPLS Multi-Protocol Label Switching NAT Network Address Translation QoS Quality of Service RIB Routing Information Base SCE Service Control Element SPE Service Processing Element VNE Virtual Networ
30、k Element 5 Conventions In this Supplement, the following convention is used: The keyword “Entity“ indicates CE, SCE, FE, SPE and ME. 6 Issues with current IP networks The original IP networks were simply designed to support easy internetworking and best-effort communication for research use. Curren
31、tly, IP networks have been widely deployed for commercial usage on a huge network scale and user scale, which will continue to increase rapidly. More and more new services, features and capabilities have been introduced into the IP networks. Currently serving as the most important public data networ
32、ks, the existing IP networks are encountering serious architectural problems as they evolve. These problems include issues related to capacity, scalability, controllability, security and QoS. With the continued rapid increase in the number of users and their bandwidth and service requirements, the s
33、calability and functionality for the network nodes and the whole network are of major concern. The control plane is becoming more and more complex. Scalability and controllability of the control plane, the management plane and the data plane of network nodes and the whole IP network are major challe
34、nges for future evolution. The major reason for issues related to the scalability and controllability of todays IP networks is that the functional architecture of the control plane is not optimal. In an IP network, the control plane and the data plane are integrated into a network node, and more and
35、 more control signalling and service functionalities are added into the network node. IP networks have become complex, thus making it difficult to maintain or extend. Separation of the control plane from the data plane can alleviate scalability and controllability problems related to the current IP
36、networks. Therefore, separation of the control plane and the data plane can improve the robustness of IP networks. Y series Supplement 11 (01/2010) 3 7 Overview of the iSCP Figure 7-1 shows the relationship among three planes and the re-constructible components of the iSCP. The control plane contain
37、s mechanisms dealing with the network services and deciding the pathways for user traffic. These mechanisms will be implemented in CEs and SCEs. The data plane contains mechanisms forwarding and processing user traffic. These mechanisms will be implemented in FEs and SPEs. The management plane conta
38、ins mechanisms dealing with the operation, administration, and management aspects of the iSCP network. These mechanisms will be implemented in MEs. Y.Sup.11(10)_F7-1CE CE SCE SCEFE FE SPE SPEData planeVNEControl planeMEManagementplaneFigure 7-1 Overview of the iSCP In the iSCP, a single conventional
39、 network element, e.g., a router, can be constructed using multiple network elements such as CEs, SCEs, FEs and SPEs. The constructed element is called a virtual network element (VNE). Depending on the required capacity and flexibility, the number of individual elements used for VNE can vary. In a t
40、ypical use case, a small number (e.g., one, or two in case of redundancy) of CEs controls a large number of FEs. In a VNE, one CE in the control plane can control one or a group of FE(s) in the data plane. The CE will generate the rules for FE(s) to forward certain traffic, and download the rules to
41、 FE(s). To generate these rules, the CE maintains necessary information in a routing information base (RIB) to compute the most suitable route for incoming packets. The RIB is updated by communication with other CEs by routing protocols. Then CE(s) generate a forwarding information base (FIB) based
42、on the RIB and download the FIB to the FE(s). One SCE in the control plane can control associated SPE(s) in the data plane. The SCE will generate the rules for SPE(s) to process certain traffic. These rules are based on service policies, configured by ME(s) and maintained as a service control table.
43、 For example, service policies include quality of service (QoS) behaviour policies and access control policies. The SCE enforces the rules by setting service control table(s) to the associated SPE(s). An FE in the data plane forwards incoming packets according to the FIB, which is generated and give
44、n by the CE(s). The FE receives and updates the FIB from the CE, looks up the FIB to obtain the next hop information of packets, and forwards the packets. An SPE in the data plane handles incoming packets according to the service control table. The SPE receives and updates the service control table
45、from the associated SCE(s), looks up the service control table, and handles packets according to the service control table. The SPE can process the packets such as NAT, encryption/decryption, protocol conversion and content processing, etc. An ME in the management plane manages resources of CE(s), S
46、CE(s), FE(s) and SPE(s) in terms of configuration, fault and performance management. 4 Y series Supplement 11 (01/2010) 8 Application scenarios 8.1 Cluster router scenarios A cluster router system consists of multiple entities, such as CE(s), SCE(s), FE(s), SPE(s) and ME(s). The ME(s) manage resourc
47、es of all entities. And the ME(s) may partition them into multiple re-constructible VNEs. A VNE is a virtual router which consists of multiple CE(s), SCE(s), FE(s) and SPE(s) which belong to the cluster router system. The VNE is a logical routing node (routing is only one hop) in a network, but not
48、a subnet. The VNE can support network scalability easily and provide high throughput with an appropriate number of entities for the application service traffic (video, voice or data). 8.1.1 Multiple entities connected with a switch fabric As shown in Figure 8-1, multiple entities are connected with
49、a switch fabric. The whole system can be partitioned into one or multiple VNEs. Every VNE uses the switch fabric to internally connect, and presents only one routing hop. An SCE can support to add control entities related to the third-party value-added services. An SPE can support to add processing entities related to the third-party value-added services. Figure 8-1 Cluster router system consisting of multiple entities connected with a switch fabric 8.1.2 Multiple entities connected with an optical or Ethernet switch net
