1、 ETSI TR 103 351 V1.1.1 (2017-07) Satellite Earth Stations and Systems (SES); Multi-link routing scheme in hybrid access network with heterogeneous links TECHNICAL REPORT ETSI ETSI TR 103 351 V1.1.1 (2017-07) 2 Reference DTR/SES-00373 Keywords broadband, satellite, terrestrial ETSI 650 Route des Luc
2、ioles F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N 348 623 562 00017 - NAF 742 C Association but non lucratif enregistre la Sous-Prfecture de Grasse (06) N 7803/88 Important notice The present document can be downloaded from: http:/www.etsi.org/stand
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7、opyright and the foregoing restriction extend to reproduction in all media. ETSI 2017. All rights reserved. DECTTM, PLUGTESTSTM, UMTSTMand the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members. 3GPPTM and LTE are Trade Marks of ETSI registered for the benefit of its Members
8、 and of the 3GPP Organizational Partners. oneM2M logo is protected for the benefit of its Members. GSM and the GSM logo are Trade Marks registered and owned by the GSM Association. ETSI ETSI TR 103 351 V1.1.1 (2017-07) 3 Contents Intellectual Property Rights 4g3Foreword . 4g3Modal verbs terminology
9、4g31 Scope 5g32 References 5g32.1 Normative references . 5g32.2 Informative references 5g33 Definitions and abbreviations . 6g33.1 Definitions 6g33.2 Abbreviations . 6g34 Hybrid access network with heterogeneous links 7g34.1 Architecture overview 7g34.2 IUG and ING functional architecture . 8g35 Mul
10、ti link routing with traffic dichotomy 8g35.1 Introduction 8g35.2 TCP traffic splitting and recombining plus UDP traffic forwarding 9g35.2.1 Overview 9g35.2.2 Concept of a TCP object . 10g35.2.3 Detecting an object . 12g35.2.3.1 Overview . 12g35.2.3.2 Calculation of IAT-ING-Thresh 13g35.2.3.3 Calcul
11、ation of IAT-IUG-Thresh 13g35.2.4 Classification of objects 14g35.3 Link selection for TCP traffic. 14g35.4 Link estimation for TCP traffic 14g36 Conclusion 17g3Annex A: Experimental Results 18g3A.1 Test description 18g3A.2 GEO/LEO Satellite link combined with ADSL link in an hybrid architecture 18g
12、3A.3 ADSL link combined with a 4G/LTE access in an hybrid architecture . 19g3History 20g3ETSI ETSI TR 103 351 V1.1.1 (2017-07) 4 Intellectual Property Rights Essential patents IPRs essential or potentially essential to the present document may have been declared to ETSI. The information pertaining t
13、o 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 ETSI standards“, which is available from the ETSI Secretariat. L
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15、I Web server) which are, or may be, or may become, essential to the present document. Trademarks The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners. ETSI claims no ownership of these except for any which are indicated as being the prope
16、rty of ETSI, and conveys no right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks. Foreword This Technical Report (TR) has been p
17、roduced by ETSI Technical Committee Satellite Earth Stations and Systems (SES). Modal verbs terminology In the present document “should“, “should not“, “may“, “need not“, “will“, “will not“, “can“ and “cannot“ are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms
18、for the expression of provisions). “must“ and “must not“ are NOT allowed in ETSI deliverables except when used in direct citation. ETSI ETSI TR 103 351 V1.1.1 (2017-07) 5 1 Scope The present document proposes and analyses a traffic distribution architecture for hybrid access networks combining one o
19、r several terrestrial access technologies (fixed or mobile service) together with a satellite broadband access network (Fixed Satellite Service). The traffic distribution architecture will enhance the end users Quality of Experience by efficiently utilizing all available connections simultaneously u
20、sing the Multipath TCP protocol. It allows for splitting traffic flows into smaller chunks, so-called objects, for which the most appropriated link is selected. The architecture is complemented by a Capacity and Link Status Estimation process that estimates link characteristics by passively monitori
21、ng TCP traffic, so that the Link Selection can be performed on a more informed basis. The present document aims at: Defining the usage of the Multipath TCP protocol in Hybrid FSS satellite/terrestrial architecture. Proposing a method to split TCP traffic into connected chunks of traffic to ease the
22、multipath routing. Proposing a routing scheme that distributes traffic intelligently among the available connections. Proposing a TCP-based link estimation method to passively determine available bandwidth and latency of a path. 2 References 2.1 Normative references Normative references are not appl
23、icable in the present document. 2.2 Informative references References are either specific (identified by date of publication and/or edition number or version number) or non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the refer
24、enced document (including any amendments) applies. NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee their long term validity. The following referenced documents are not necessary for the application of the present document but they assis
25、t the user with regard to a particular subject area. i.1 ETSI TR 103 272: “Satellite Earth Stations and Systems (SES); Hybrid FSS satellite/terrestrial network architecture for high speed broadband access“. i.2 IETF RFC 6824 (2013) (Ford A., Raiciu C., Handley M. this scenario is expected to be well
26、 suited on a low delay link. Long.scen: cat 5 Mbytes remote file; this scenario is expected to be well suited on a high bandwidth link. Mixed.scen: all the commands in 2 above files; this scenario is expected to be well suited on a link having both an high bandwidth and a low RTT. It is important to
27、 note that SSH communications are encrypted. In this test a real prototype was used, connected to real networks and implementing the above described algorithms and methods. The test was run in an ADSL+Satellite and an ADSL+4G architectures. A.2 GEO/LEO Satellite link combined with ADSL link in an hy
28、brid architecture This option clause encompasses either a GEO or a LEO satellite access. In this test, the hybrid network is made of a 1 Mbps/70 ms RTT ADSL Link and a 8 Mbps/700 ms RTT Satellite link. The test is run on each link alone and on the two links using a path selection based on objects le
29、ngth + Weighted round robin algorithm. That means that flows are split in objects: Short objects are sent on the lowest RTT link (hopefully ADSL) and long objects are sent in the weighted round robin mode on the ADSL (weight = 1) and Satellite (weight = 8) link. The results are shown in Table A.1 an
30、d demonstrate as expected that this hybrid satellite + ADSL architecture performs as an equivalent 9 Mbps link with 70 ms RTT. This looks like the satellite being placed not on the GEO but near the ground. The results for the long scenario in hybrid mode are better than those that would be seen with
31、 a simple bandwidth aggregation This is due to the fact that the TCP establishment time + Ssh handshake take about 9 s on a satellite link and only about 2 s on a ADSL link. In the hybrid mode implementation the TCP establishment of the satellite subflow is done via the ADSL link and the ssh initial
32、ization messages are also sent as short objects via the ADSL link. ETSI ETSI TR 103 351 V1.1.1 (2017-07) 19 Table A.1: Execution time of the three SSH based scenarios (Short, long and mixed) over different combinations of access links (ADSL, satellite or parallel combining of both) Scenario executio
33、n time (seconds) ADSL only Satellite only ADSL+Satellite (with PSBOL+WRR scheme) Gain Vs ADSL Gain vs Sat Short 10 79 10 0 % 87 % Long 47 19 10 79 % 47 % Mixed 56 70 17 70 % 76 % A.3 ADSL link combined with a 4G/LTE access in an hybrid architecture In this test, the hybrid network is made of a 2,5 M
34、bs/70 ms RTT ADSL Link and a 15 Mbs/75 ms RTT LTE link. The test is run on each link alone and on the two links using a path selection based on objects length + Offload. That means that flows are split in objects: Short objects are sent on the lowest RTT link (hopefully ADSL) long objects are sent i
35、n offload mode on the ADSL until the 2,5 Mbs limit is reached and on the 4G/LTE link after. The test is done on a loaded network .the load being obtained by download of a 20 MB file running in loop. Only the results for the mixed scenario are shown due to a limited access time to the foreign test pl
36、atform. The results are shown in Table A.2 and demonstrate that in this pure terrestrial hybrid architecture the multilink network performs as an equivalent 17,5 Mbs/70 ms RTT and delivers substantial user experience gain compared to the non-hybrid situation with each link used alone. Looking a bit
37、more to the logs during the test it appears that the RTT of the 4G/LTE link increases from 75 ms up to 200 ms. This is due to the offload algorithm that does not overload the ADSL link and keeps its RTT stable at the same time the data in excess are sent over LTE that is overloaded and the QoS queue
38、s are filed introducing some latency. Table A.2: Execution time of the mixed SSH based scenarios over different combinations of access links (ADSL, 4G/LTE or parallel combining of both) under typical network load conditions Scenario execution time (seconds) ADSL LTE ADSL+LTE PSBOL +Offload Gain Vs ADSL Gain Vs LTE Mixed 49 22 13,5 73 % 39 % ETSI ETSI TR 103 351 V1.1.1 (2017-07) 20 History Document history V1.1.1 July 2017 Publication
