1、 ETSI TR 102 676 V1.1.1 (2009-11)Technical Report Satellite Earth Stations and Systems (SES);Broadband Satellite Multimedia (BSM);Performance Enhancing Proxies (PEPs)ETSI ETSI TR 102 676 V1.1.1 (2009-11) 2Reference DTR/SES-00294 Keywords architecture, broadband, IP, management, multimedia, satellite
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6、ssion. The copyright and the foregoing restriction extend to reproduction in all media. European Telecommunications Standards Institute 2009. All rights reserved. DECTTM, PLUGTESTSTM, UMTSTM, TIPHONTM, the TIPHON logo and the ETSI logo are Trade Marks of ETSI registered for the benefit of its Member
7、s. 3GPPTM is a Trade Mark of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. LTE is a Trade Mark of ETSI currently being registered for the benefit of its Members and of the 3GPP Organizational Partners. GSM and the GSM logo are Trade Marks registered and owne
8、d by the GSM Association. ETSI ETSI TR 102 676 V1.1.1 (2009-11) 3Contents Intellectual Property Rights 5g3Foreword . 5g3Introduction 5g31 Scope 6g32 References 6g32.1 Normative references . 6g32.2 Informative references 6g33 Definitions and abbreviations . 8g33.1 Definitions 8g33.2 Abbreviations . 9
9、g34 Need for PEPs in BSM networks . 10g34.1 Performance improvement using standard end-to-end techniques . 10g34.2 Motivation for using PEPs . 10g34.3 PEP terminal architecture and components 11g34.4 PEP scenarios . 13g34.4.1 Scenario 1: Single user . 13g34.4.2 Scenario 2: Independent satellite and
10、PEP gateways 14g34.4.3 Scenario 3: Multiple PEP Gateways . 15g34.4.4 Scenario 4: Integrated PEP (single PEP) 16g34.5 Cross layer improvements 16g35 Security impact on Performance Enhancing Proxies . 18g35.1 Previous research work related to PEP security . 18g35.2 Security solutions for BSM PEPs . 19
11、g35.2.1 Interworking between PEPs and transport/application layer security systems . 19g35.2.2 Interworking between PEPs and IPsec 20g35.2.3 Interworking between PEPs and link layer security systems 21g35.3 BSM link layer security architecture suitable for PEPs 22g36 Analysis of PEP deployment impac
12、t on current and future BSM architecture 23g3Annex A: End-to-end options and improvement techniques . 24g3A.1 TCP end-to-end techniques 24g3A.2 Application layer end-to-end techniques 24g3Annex B: PEPs options and improvement techniques 26g3B.1 PEPs types and classifications 26g3B.2 TCP PEP (T-PEP)
13、techniques 27g3B.3 Application layer PEP (A-PEP) techniques . 29g3Annex C: Summary of techniques used by PEP manufacturers . 30g3Annex D: Examples of distributed and integrated PEPs 31g3D.1 Application layer PEP: Hughes HPEP . 31g3D.2 Distributed TCP PEP: Satlabs I-PEP 32g3D.2.1 TCP Noordwijk 34g3D.
14、3 Integrated PEP: PEPsal 35g3Annex E: Example cross layer improvement for FTP data flows . 38g3ETSI ETSI TR 102 676 V1.1.1 (2009-11) 4Annex F: Bibliography 41g3History 42g3ETSI ETSI TR 102 676 V1.1.1 (2009-11) 5Intellectual Property Rights IPRs essential or potentially essential to the present docum
15、ent may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR 000 314: “Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of
16、ETSI standards“, which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http:/webapp.etsi.org/IPR/home.asp). Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existe
17、nce of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to the present document. Foreword This Technical Report (TR) has been produced by ETSI Technical Committee Satellite Earth Stations and Systems (SES). Introducti
18、on The present document presents an overview of PEP issues over satellites and focuses on BSM-related issues. It is based on current ETSI BSM architecture documents i.1 and i.2. Also it is aligned with the relevant IETF standards. The IETF documented general PEP issues are described in RFC 3135 i.3.
19、 However, RFC 3135 i.3 is not satellite specific and, more importantly, is now seven years old. Also the present document is aligned with the Satlabs group solution called Interoperable PEP (I-PEP) that is aimed at DVB-RCS systems i.4. ETSI ETSI TR 102 676 V1.1.1 (2009-11) 61 Scope The present docum
20、ent aims to describe the current solutions for Performance Enhancing Proxies in broadband multimedia satellite systems. The range of PEPs considered includes TCP accelerators, TCP header compression and HTTP proxies. The PEPs are classified in terms of ease of implementation, interworking capability
21、 with other PEPs and performance potential. Analysis of various PEP types/mechanisms and recommendations are made for using PEPs in BSM networks. Also recommendations are made for further work to support the introduction of PEPs in satellite systems, and in particular their introduction into the BSM
22、 architectures and standards. 2 References References are either specific (identified by date of publication and/or edition number or version number) or non-specific. For a specific reference, subsequent revisions do not apply. Non-specific reference may be made only to a complete document or a part
23、 thereof and only in the following cases: - if it is accepted that it will be possible to use all future changes of the referenced document for the purposes of the referring document; - for informative references. Referenced documents which are not found to be publicly available in the expected loca
24、tion might be found at http:/docbox.etsi.org/Reference. NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee their long term validity. 2.1 Normative references The following referenced documents are indispensable for the application of the pr
25、esent document. For dated references, only the edition cited applies. For non-specific references, the latest edition of the referenced document (including any amendments) applies. Not applicable. 2.2 Informative references The following referenced documents are not essential to the use of the prese
26、nt document but they assist the user with regard to a particular subject area. For non-specific references, the latest version of the referenced document (including any amendments) applies. i.1 ETSI TS 102 465: “Satellite Earth Stations and Systems (SES); Broadband Satellite Multimedia (BSM); Genera
27、l Security Architecture“. i.2 ETSI TS 102 292: “Satellite Earth Stations and Systems (SES); Broadband Satellite Multimedia (BSM) services and architectures; Functional architecture for IP interworking with BSM networks“. i.3 IETF RFC 3135 (June 2001): “Performance Enhancing Proxies Intended to Mitig
28、ate Link-Related Degradations“. i.4 I-PEP specifications, Issue 1a. Satlabs group recommendations (October 2005). NOTE: Available at http:/www.satlabs.org. ETSI ETSI TR 102 676 V1.1.1 (2009-11) 7i.5 ETSI TS 102 463: “Satellite Earth Stations and Systems (SES); Broadband Satellite Multimedia (BSM); I
29、nterworking with IntServ QoS“. i.6 ETSI TS 102 464: “Satellite Earth Stations and Systems (SES); Broadband Satellite Multimedia (BSM); Interworking with DiffServ Qos“. i.7 ETSI TS 102 466, “Satellite Earth Stations and Systems (SES); Broadband Satellite Multimedia (BSM); Multicast Security Architect
30、ure“. i.8 IETF RFC 4326: “Unidirectional Lightweight Encapsulation (ULE) for Transmission of IP Datagrams over an MPEG-2 Transport Stream (TS)“. i.9 ETSI EN 301 790: “Digital Video Broadcasting (DVB); Interaction channel for satellite distribution systems“. i.10 Xiplink. NOTE: See http:/ i.11 Space
31、Bel - SPB-FS-651-DS-001 (February 2004): “FastSat“. NOTE: Available at http:/www.spacebel.be/FR/Space/FastSatDataSheet.pdf. i.12 HUGHES: “Delivering outstanding application performance over satellite“. NOTE: Available at: http:/ i.13 IEEE A 8:213-230. Wiley InterScience. i.23 ESA ARTES-1 programme,
32、2006: “Transport Protocol for DVB-RCS Interoperable PEP“. ETSI ETSI TR 102 676 V1.1.1 (2009-11) 8i.24 C. Roseti and E.Kristiansen: “TCP behaviour in a DVB-RCS environment“. In Proceedings 24thAIAA International Communications Satellite Systems Conference (ICSSC), San Diego, 2006. i.25 IETF RFC 4614
33、(September 2006): “A Roadmap for Transmission Control Protocol (TCP) Specification Documents“. i.26 IETF RFC 2581 (April 1999): “TCP Congestion Control“. i.27 Space Communications Protocol Specification (SCPS)-Transport Protocol (SCPS-TP). “Recommendation for Space Data System Standards, CCSDS 714.0
34、-B-2“. Blue Book. Issue 2. Washington, D.C.: CCSDS, October 2006. i.28 C. Dovrolis, P. Ramanathan, D. Moore, “What do packet dispersion techniques measure?“, in Proceedings of IEEE INFOCOM, pp. 905-914, Apr. 2001. i.29 M. Karaliopoulos, R. Tafazzoli, B.G. Evans, “Providing Differentiated Services to
35、 TCP Flows Over Bandwidth on Demand Geostationary Satellite Networks“, IEEE Journal on Selected Areas in Communications, vol. 22, No. 2, Feb. 2004. i.30 M. Sooriyabandara, G. Fairhurst, “Dynamics of TCP over BoD satellite networks, International Journal of Satellite Communications and Networking“, V
36、ol. 21, No. 4-5, Jul. 2055, pp. 427-449. i.31 M. Luglio, C. Roseti, F. Zampognaro, “Performance evaluation of TCP-based applications over DVB-RCS DAMA schemes“, International Journal of Satellite Communications and Networking, Vol. 27, Issue 3, pp. 163-191, Published online 2 Mar 2009, DOI: 10.1002/
37、sat.930. i.32 IETF RFC 5374: “Multicast Extensions to the Security Architecture for the Internet Protocol“. i.33 IETF RFC 793: “Transmission Control Protocol“. i.34 IETF RFC 1122: “Requirements for Internet Hosts - Communication Layers“. 3 Definitions and abbreviations 3.1 Definitions For the purpos
38、es of the present document, the following terms and definitions apply: distributed PEP: PEP client and server are located at both ends of the satellite link (BSM ST and Gateway) GateWay PEP (GW PEP): PEP server located near the BSM Gateway integrated PEP: there is only one PEP entity residing with t
39、he satellite gateway (BSM Gateway) interoperable PEP (I-PEP): functional architecture assumes a split-connection approach with the I-PEP server and a client both capable of supporting the I-PEP protocol NOTE 1: The I-PEP protocol consists of a transport protocol heavily based on TCP and modified/aug
40、mented by SCPS-TP as well as a session protocol comprising several optional additions to support service and session management. NOTE 2: Specified by the ESA/Satlabs i.4 and aims to provide enhancement for satellite-based communications. Performance Enhancing Proxy (PEP): network agents designed to
41、improve the end-to-end performance of some communications protocol such as Transmission Control Protocol (TCP) NOTE: More information on Transmission Control Protocol (TCP) is available at http:/en.wikipedia.org/wiki/Transmission_Control_Protocol. ST PEP: PEP client located near the BSM ST terminal
42、ETSI ETSI TR 102 676 V1.1.1 (2009-11) 93.2 Abbreviations For the purposes of the present document, the following abbreviations apply: ACCE ACK-based Capacity and Congestion Estimation ACK ACKnowledgement A-PEP Application layer PEP BDP Bandwidth Delay Product BSM Broadband Satellite Multimedia CCSDS
43、 Consultative Committee for Space Data Systems cwnd congestion window (TCP) DAMA Demand Assignment Multiple Access DNS Domaine Name System DVB-RCS Digital Video Broadcasting - Return Channel for Satellites ESP Encapsulated Security Protocol FSS Fixed Service Satellite FTP File Transfer Protocol GW P
44、EP GateWay PEP HPEP HTTP PEP ICMP Internet Control Message Protocol IP Internet Protocol ISP Internet Service Provider LAN Local Area Network M-ESP Modified ESP MF-TDMA Multi Frequency - Time Division Multiple Access MIB Management Information Base ML-IPSEC Multilayer IPSEC protocol MPE Multi Protoc
45、ol Encapsulation MSS Maximum Segment Size MTU Maximum Transmission Unit NCC Network Control Centre PEP Performance Enhancing Proxy QID Queue ID QIDSPEC Queue ID SPECifications QoS Quality of Service RTO Retransmission Time Out RTT Round-Trip Time RWIN Receive WINdowSACKs Selective ACKnowledgements S
46、CPS Space Communications Protocol Specification SCPS-TP Space Communications Protocol Specification-Transport Protocol SID Security association IDentity SIP Session Initiation Protocol SI-SAP Satellite Independent - Service Access Point SSL Secure Socket LayerST Satellite Terminal TBTP Terminal Burs
47、t Time Plan TCP Transmission Control Protocol TCPN TCP Noordwijk TF-ESP Transport Friendly - ESP TLS Transport Layer Security T-PEP TCP (transport) layer - PEP UDP User Datagram Protocol ULE Unidirectional Lightweight Encapsulation UMTS Universal Mobile Telephone System URL Uniform Resource Locator
48、VPN Virtual Private Network X-SAP Cross Layer Service Access Point ETSI ETSI TR 102 676 V1.1.1 (2009-11) 104 Need for PEPs in BSM networks 4.1 Performance improvement using standard end-to-end techniques The original Internet adopted an end-to-end architecture, where a transport connection was betwe
49、en a pair of hosts, bound to a globally unique IP address and locally meaningful transport port at each end host. The literature background for end-to-end improvements to TCP and HTTP (without using PEPs) is presented in clauses A.1 and A.2. There are two main reasons in favour of using end-to-end mechanisms for improving performance over satellite links: 1) End-to-end mechanisms are based on stan
