ETSI TS 102 636-5-1 V1.1.1 (2011-02)

Intelligent Transport Systems (ITS); Vehicular Communications; GeoNetworking; Part 5: Transport Protocols; Sub-part 1: Basic Transport Protocol

DTS/ITS-0030006

General Information

• Status: Published
• Publication Date: 01-Feb-2011
• Technical Committee: ITS WG3 - Transport and Network
• Current Stage: 12 - Completion
• Due Date: 07-Feb-2011
• Completion Date: 02-Feb-2011
• Mandate: M/453

Standards Content (Sample)

Technical Specification
Intelligent Transport Systems (ITS);
Vehicular Communications;
GeoNetworking;
Part 5: Transport Protocols;
Sub-part 1: Basic Transport Protocol

2 ETSI TS 102 636-5-1 V1.1.1 (2011-02)

Reference
DTS/ITS-0030006
Keywords
addressing, ITS, network, point-to-multipoint,
point-to-point, protocol
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ETSI
3 ETSI TS 102 636-5-1 V1.1.1 (2011-02)
Contents
Intellectual Property Rights . 4
Foreword . 4
Introduction . 4
1 Scope . 5
2 References . 5
2.1 Normative references . 5
2.2 Informative references . 5
3 Definitions and abbreviations . 6
3.1 Definitions . 6
3.2 Abbreviations . 6
4 Services provided by the Basic Transport Protocol . 6
5 Format convention . 7
6 BTP packet structure . 8
7 BTP header . . 8
7.1 Overview . 8
7.2 BTP-A header . 9
7.2.1 Structure of the BTP-A header . 9
7.2.2 Fields of the BTP-A header . 9
7.3 BTP-B header . 9
7.3.1 Structure of the BTP-B header . 9
7.3.2 Fields of the BTP-B header . 9
8 Protocol operations . . 10
8.1 General . 10
8.2 Source operations . 10
8.3 Destination operations . 11
Annex A (informative): BTP data services . 12
A.1 General . 12
A.2 BTP-Data.request . . 12
A.3 BTP-Data.indication . 13
Annex B (informative): Bibliography . 14
History . 15

ETSI
4 ETSI TS 102 636-5-1 V1.1.1 (2011-02)
Intellectual 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: "Intellectual 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://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 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 Technical Specification (TS) has been produced by ETSI Technical Committee Intelligent Transport System (ITS).
The present document is part 5, sub-part 1 of a multi-part deliverable covering Networking and Transport, as identified
below:
Part 1: "Requirements";
Part 2: "Scenarios";
Part 3: "Network architecture";
Part 4: "Geographical addressing and forwarding for point-to-point and point-to-multipoint communications";
Part 5: "Transport Protocols":
Sub-part 1: "Basic Transport Protocol";
Part 6: "Internet Integration".
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 DEN services, for the transmission of packets via the GeoNetworking protocol as well as the de-multiplexing at the
destination). BTP enables the protocol entities at the ITS Facilities layer to access services of the GeoNetworking
protocol and to pass protocol control information between the ITS Facilities layer and the GeoNetworking protocol.
Message multiplexing/demultiplexing is based on ports, an ITS station-internal, 16 bit address. A port represents a
communication endpoint that identifies the ITS station protocol entity at the source (source port) and 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 UDP the multiplexing/demultiplexing of 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 packet to the entities at the ITS Facilities layer. BTP also adopts the concept
of "well-known ports" from the IP protocol suites that assigns fixed ports to specific ITS Facilities layer protocols. The
definition of the ports, however, is beyond the scope of the present standard.
BTP is a lightweight protocol: It has a 4-byte protocol header and requires minimal processing. It provides an unreliable
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
5 ETSI TS 102 636-5-1 V1.1.1 (2011-02)
1 Scope
The present document specifies the ITS Basic Transport Protocol (BTP) for the transport of packets among ITS stations
in the ITS ad hoc network. 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 references, 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 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 TS 102 636-1: "Intelligent Transport Systems (ITS); Vehicular Communications;
GeoNetworking; Part 1: Requirements".
[3] ETSI TS 102 636-2: "Intelligent Transport Systems (ITS); Vehicular Communications;
GeoNetworking; Part 2: Scenarios".
[4] ETSI TS 102 636-3: "Intelligent Transport Systems (ITS); Vehicular Communications;
GeoNetworking; Part 3: Network architecture".
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 ES 202 663: "Intelligent Transport Systems (ITS); European profile standard for the physical
and medium access control layer of Intelligent Transport Systems operating in the 5 GHz
frequency band".
[i.2] ETSI TS 102 636-4-1: "Intelligent Transport System (ITS); Vehicular communications;
GeoNetworking; Part 4: Geographical addressing and forwarding for point-to-point and
point-to-multipoint communications; Sub-part 1: Media independent functionalities".
[i.3] 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 functionalities for ITS-G5A
media".
[i.4] ETSI TS 102 637-2: "Intelligent Transport Systems (ITS); Vehicular Communications; Basic Set
of Applications; Part 2: Specification of Cooperative Awareness Basic Service".
[i.5] IETF RFC 768: "User Datagram Protocol".
ETSI
6 ETSI TS 102 636-5-1 V1.1.1 (2011-02)
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in [1], [4] and the following apply:
destination: receiving BTP entity in the ITS station
destination port: port at which the destination is expected to listen for a BTP packet
port: ITS station-internal address that identifies a protocol entity at the ITS facilities layer
source: originating BTP entity in the ITS station
source port: port at which the source of the BTP packet is listening for a reply BTP packet
3.2 Abbreviations
For the purposes of the present document, the abbreviations given in [1], [4] and the following apply:
BTP Basic Transport Protocol
FL Facilities Layer
4 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 [4]. Similar to UDP [i.5], it offers a minimal 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 [2] and support the use cases defined in [3].
The BTP provides services to ITS Facilities Layer protocol entities (fi
...