1、 ETSI EN 302 636-5-1 V1.2.1 (2014-08) Intelligent Transport Systems (ITS); Vehicular Communications; GeoNetworking; Part 5: Transport Protocols; Sub-part 1: Basic Transport Protocol EUROPEAN STANDARD ETSI ETSI EN 302 636-5-1 V1.2.1 (2014-08)2Reference REN/ITS-0030036 Keywords addressing, autonomic n
2、etworking, ITS, network, protocol ETSI 650 Route des Lucioles 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 d
3、ocument can be downloaded from: http:/www.etsi.org The present document may be made available in electronic versions and/or in print. The content of any electronic and/or print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any exis
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5、ject to revision or change of status. Information on the current status of this and other ETSI documents is available at http:/portal.etsi.org/tb/status/status.asp If you find errors in the present document, please send your comment to one of the following services: http:/portal.etsi.org/chaircor/ET
6、SI_support.asp Copyright Notification No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm except as authorized by written permission of ETSI. The content of the PDF version shall not be modified without the written authori
7、zation of ETSI. The copyright and the foregoing restriction extend to reproduction in all media. European Telecommunications Standards Institute 2014. All rights reserved. DECTTM, PLUGTESTSTM, UMTSTMand the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members. 3GPPTM and LTE a
8、re Trade Marks of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. GSM and the GSM logo are Trade Marks registered and owned by the GSM Association. ETSI ETSI EN 302 636-5-1 V1.2.1 (2014-08)3Contents Intellectual Property Rights 4g3Foreword . 4g3Modal verbs ter
9、minology 4g3Introduction 4g31 Scope 6g32 References 6g32.1 Normative references . 6g32.2 Informative references 6g33 Definitions and abbreviations . 7g33.1 Definitions 7g33.2 Abbreviations . 7g34 Services provided by the Basic Transport Protocol . 8g35 Format convention 8g36 BTP packet structure 9g3
10、7 BTP header . 9g37.1 Overview 9g37.2 BTP-A header . 10g37.2.1 Structure of the BTP-A header . 10g37.2.2 Fields of the BTP-A header 10g37.3 BTP-B header . 10g37.3.1 Structure of the BTP-B header 10g37.3.2 Fields of the BTP-B header 11g38 Protocol operations . 11g38.1 General . 11g38.2 Source operati
11、ons . 11g38.3 Destination operations 12g3Annex A (informative): BTP data services . 13g3A.1 General . 13g3A.2 BTP-Data.request . 13g3A.3 BTP-Data.indication . 14g3Annex B (normative): Well-known BTP port numbers . 16g3Annex C (informative): Bibliography . 17g3History 18g3ETSI ETSI EN 302 636-5-1 V1.
12、2.1 (2014-08)4Intellectual Property Rights IPRs essential or potentially essential to the present document 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: “Intelle
13、ctual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards“, which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http:/ipr.etsi.org). Pursuant to the ETSI IPR Policy, no investigation, including
14、 IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence 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 European Standard (EN) has been pro
15、duced by ETSI Technical Committee Intelligent Transport Systems (ITS). The present document is part 5, sub-part 1 of a multi-part deliverable. Full details of the entire series can be found in ETSI EN 302 636-1 2. National transposition dates Date of adoption of this EN: 14 July 2014 Date of latest
16、announcement of this EN (doa): 31 October 2014 Date of latest publication of new National Standard or endorsement of this EN (dop/e): 30 April 2015 Date of withdrawal of any conflicting National Standard (dow): 30 April 2016 Modal verbs terminology In the present document “shall“, “shall not“, “shou
17、ld“, “should not“, “may“, “may not“, “need“, “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 for the expression of provisions). “must“ and “must not“ are NOT allowed in ETSI deliverables except when used in
18、direct citation. Introduction The Basic Transport Protocol (BTP) provides an end-to-end, connection-less transport service in the ITS ad hoc network. Its main purpose is the multiplexing of messages from different processes at the ITS facilities layer, e.g. CAM and DENM from the cooperative awarenes
19、s basic service and the distributed environmental notification basic service, for the transmission of packets via the GeoNetworking protocol as well as the de-multiplexing at the destination. BTP enables protocol entities at the ITS facilities layer to access services of the GeoNetworking protocol a
20、nd to pass protocol control information between the ITS facilities layer and the GeoNetworking protocol. ETSI ETSI EN 302 636-5-1 V1.2.1 (2014-08)5Message multiplexing/demultiplexing is based on ports, an ITS station-internal 16 bit address. A port represents a communication endpoint that identifies
21、 the ITS station protocol entity at the source (source port) or the destination (destination port). The usage of ports is similar to the two-stage packet transport in the IP protocol suite, where the IP provides the routing of packets from source to destination and the transport protocol, such as UD
22、P, multiplexes/demultiplexes messages from/to application processes. In the case of BTP, the GeoNetworking protocol transports the packets among the ITS stations and the BTP protocol delivers the packets to the entities at the ITS facilities layer. BTP also adopts the concept of “well-known ports“ f
23、rom the IP protocol suite that assigns fixed ports to specific ITS facilities layer protocols. The definition of the ports, however, is beyond the scope of the present document. BTP is a lightweight protocol: It has a 4-byte protocol header and requires minimal processing. It provides an unreliable
24、transport of packets, i.e. packets can arrive out-of-order, appear duplicated or can be lost. The design of BTP assumes that entities using the protocol are either tolerant against the unreliable packet transport or provide appropriate mechanisms for reliable communication in their protocols. ETSI E
25、TSI EN 302 636-5-1 V1.2.1 (2014-08)61 Scope The present document specifies the Basic Transport Protocol (BTP) for the transport of packets among ITS stations. It resides on top of the GeoNetworking protocol specified in ETSI EN 302 636-4-1 5 and ETSI TS 102 636-4-2 i.2 and below the ITS-S facilities
26、 layer. It provides an end-to-end, connection-less and unreliable transport service. 2 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 refe
27、rences, the latest version of the reference document (including any amendments) applies. Referenced documents which are not found to be publicly available in the expected location might be found at http:/docbox.etsi.org/Reference. NOTE: While any hyperlinks included in this clause were valid at the
28、time of publication, ETSI cannot guarantee their long term validity. 2.1 Normative references The following referenced documents are necessary for the application of the present document. 1 ETSI EN 302 665: “Intelligent Transport Systems (ITS); Communications Architecture“. 2 ETSI EN 302 636-1: “Int
29、elligent Transport Systems (ITS); Vehicular Communications; GeoNetworking; Part 1: Requirements“. 3 ETSI EN 302 636-2: “Intelligent Transport Systems (ITS); Vehicular Communications; GeoNetworking; Part 2: Scenarios“. 4 ETSI TS 102 636-3: “Intelligent Transport Systems (ITS); Vehicular Communication
30、s; GeoNetworking; Part 3: Network architecture“. 5 ETSI EN 302 636-4-1: “Intelligent Transport Systems (ITS); Vehicular Communications; GeoNetworking; Part 4: Geographical addressing and forwarding for point-to-point and point-to-multipoint communications; Sub-part 1: Media-Independent Functionality
31、“. 2.2 Informative references The following referenced documents are not necessary for the application of the present document but they assist the user with regard to a particular subject area. i.1 ETSI EN 302 663: “Intelligent Transport Systems (ITS); Access layer specification for Intelligent Tran
32、sport Systems operating in the 5 GHz frequency band“. i.2 ETSI TS 102 636-4-2: “Intelligent Transport Systems (ITS); Vehicular Communications; GeoNetworking; Part 4: Geographical addressing and forwarding for point-to-point and point-to-multipoint communications; Sub-part 2: Media-dependent function
33、alities for ITS-G5“. i.3 ETSI EN 302 637-2: “Intelligent Transport Systems (ITS); Vehicular Communications; Basic Set of Applications; Part 2: Specification of Cooperative Awareness Basic Service“. i.4 ETSI EN 302 637-3: “Intelligent Transport Systems (ITS); Vehicular Communications; Basic Set of Ap
34、plications; Part 3: Specifications of Decentralized Environmental Notification Basic Service“. i.5 ETSI TS 102 890-2: “Intelligent Transport Systems (ITS); Facilities layer function; Part 2: Services announcement specification“. ETSI ETSI EN 302 636-5-1 V1.2.1 (2014-08)7i.6 IETF RFC 768: “User Datag
35、ram Protocol“. i.7 ISO/IEC 8802-2: “Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Specific requirements; Part 2: Logical Link Control“. i.8 ISO EN 17419: “Intelligent Transport Systems - Cooperative Systems - Classificat
36、ion and management of ITS applications in a global context“. i.9 ISO TS 19091: “Intelligent transport systems - Cooperative Systems - SPAT (Signal Phase and Timing) message, MAP (Intersection topology) message harmonization and profile to SAE J2735“. 3 Definitions and abbreviations 3.1 Definitions F
37、or the purposes of the present document, the terms and definitions given in ETSI EN 302 665 1, ETSI TS 102 636-3 4 and the following apply: BTP-PDU: protocol Protocol Data Unit exchanged between BTP peer entities destination: receiving BTP entity in the ITS station destination port: port at which th
38、e destination is expected to listen for a BTP packet GN-PDU: protocol Data Unit exchanged between peer entities of the GeoNetworking protocol ITS-FPCI: protocol Control Information passed from the ITS Facilities layer to the BTP port: ITS station-internal address that identifies a protocol entity at
39、 the ITS facilities layer and represents an endpoint of a logical connection source: originating BTP entity in the ITS station source port: port identifying the originating protocol entity at the ITS facilities layer NOTE: Such an entity may be listening for a reply BTP packet. 3.2 Abbreviations For
40、 the purposes of the present document, the abbreviations given in ETSI EN 302 665 1, ETSI TS 102 636-3 4 and the following apply: BTP Basic Transport Protocol BTP-PDU Basic Transport Protocol Protocol Data Unit BTP-SAP Basic Transport Protocol Service Access Point GN-PDU GeoNetworking protocol PDU e
41、xchanged between peer entities of the GeoNetworking protocol GN-SAP GeoNetworking Service Access Point ITS-FPCI ITS Facility layer Protocol Control Information ITS-FPDU ITS Facilities layer Protocol Data Unit ITS-FSDU ITS Facilities layer Service Data Unit LLC Logical Link Control PCI Protocol Contr
42、ol Information ETSI ETSI EN 302 636-5-1 V1.2.1 (2014-08)84 Services provided by the Basic Transport Protocol The Basic Transport Protocol (BTP) provides an end-to-end, connection-less transport service in the ITS ad hoc network (ETSI TS 102 636-3 4). Similar to UDP (RFC 768 i.6), it offers a minimal
43、 transport service, i.e. the non-guaranteed delivery of BTP-PDUs among BTP entities. It also allows protocol entities at the ITS facilities layer to directly access the services provided by the GeoNetworking protocol. The BTP shall meet the requirements specified in ETSI EN 302 636-1 2 and support t
44、he use cases defined in ETSI EN 302 636-2 3. The BTP provides services to ITS facilities layer protocol entities (figure 1), such as cooperative awareness basic service (ETSI EN 302 637-2 i.3) and DEN basic service (ETSI EN 302 637-3 i.4). The services are provided via the BTP-SAP using service prim
45、itives of different types that carry parameters, i.e. Protocol Control Information (ITS-FPCI), and the PDU of the upper protocol entity, i.e. ITS-FPDU. In order to provide its packet transport services, BTP uses the services of the GeoNetworking protocol (ETSI EN 302 636-4-1 5). Figure 1: SAPs, SDUs
46、 and PDUs relevant for the BTP The present document specifies the following SAPs: BTP-SAP between BTP and the ITS facilities layer; and BTP-Mgmt-SAP between the BTP and the ITS Network and Transport Management. 5 Format convention The basic convention for the specification of packet formats is illus
47、trated in figure 2. The bits are grouped into octets. The bits of an octet are always shown horizontally and are numbered from 0 to 7. Up to 4 octets are shown horizontally; multiple sets of 4 octets are grouped vertically. Octets are numbered from 0 to N-1. ETSI ETSI EN 302 636-5-1 V1.2.1 (2014-08)
48、90 1 2 3 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 Octet 0 Octet 1 Octet 2 Octet 3 Octet 4 to Octet 7 Octet N-1Figure 2: Format convention When (a part of) an octet represents a numeric quantity, the leftmost bit in the diagram is the most significant bit. Similarly when a nume
49、ric value spans multiple octet fields the leftmost field is the most significant (i.e. Big Endian or Network Byte Order). EXAMPLE: The decimal value 199 is represented as shown below: 0 1 2 3 4 5 6 7 1 1 0 0 0 1 1 1 6 BTP packet structure As specified in ETSI TS 102 636-3 4, the BTP is used in the GeoNetwork protocol stack (ETSI TS 102 636-3 4, clause 7.3.2). A BTP packet shall be comprised of the protocol headers and the payload as depicted in figure 3: The MAC header is the header of the MAC pro
