ETSI TS 138 422-2018 5G NG-RAN Xn signalling transport (V15 0 0 3GPP TS 38 422 version 15 0 0 Release 15).pdf

1、 ETSI TS 138 422 V15.0.0 (2018-07) 5G; NG-RAN; Xn signalling transport (3GPP TS 38.422 version 15.0.0 Release 15) TECHNICAL SPECIFICATION ETSI ETSI TS 138 422 V15.0.0 (2018-07)13GPP TS 38.422 version 15.0.0 Release 15Reference RTS/TSGR-0338422vf00 Keywords 5G ETSI 650 Route des Lucioles F-06921 Soph

2、ia 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/standards-search The pr

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8、ganizational Partners. oneM2M logo is protected for the benefit of its Members. GSMand the GSM logo are trademarks registered and owned by the GSM Association. ETSI ETSI TS 138 422 V15.0.0 (2018-07)23GPP TS 38.422 version 15.0.0 Release 15Intellectual Property Rights Essential patents IPRs essential

9、 or potentially essential to normative deliverables 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

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13、ucts, services or organizations associated with those trademarks. Foreword This Technical Specification (TS) has been produced by ETSI 3rd Generation Partnership Project (3GPP). The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or GSM

14、identities. These should be interpreted as being references to the corresponding ETSI deliverables. The cross reference between GSM, UMTS, 3GPP and ETSI identities can be found under http:/webapp.etsi.org/key/queryform.asp. Modal verbs terminology In the present document “shall“, “shall not“, “shoul

15、d“, “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 for the expression of provisions). “must“ and “must not“ are NOT allowed in ETSI deliverables except when used in direct citation. ETS

16、I ETSI TS 138 422 V15.0.0 (2018-07)33GPP TS 38.422 version 15.0.0 Release 15Contents Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 4g31 Scope 5g32 References 5g33 Definitions and abbreviations . 5g33.1 Definitions 5g33.2 Abbreviations . 5g34 Xn signalling bearer

17、 . 6g34.1 Functions and protocol stack 6g35 Data link layer 6g36 IP layer . 6g37 Transport layer . 6g3Annex A (informative): Change history . 8g3History 9g3ETSI ETSI TS 138 422 V15.0.0 (2018-07)43GPP TS 38.422 version 15.0.0 Release 15Foreword This Technical Specification has been produced by the 3r

18、dGeneration Partnership Project (3GPP). The contents of the present document are subject to continuing work within the TSG and may change following formal TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an identifying change of release

19、 date and an increase in version number as follows: Version x.y.z where: x the first digit: 1 presented to TSG for information; 2 presented to TSG for approval; 3 or greater indicates TSG approved document under change control. y the second digit is incremented for all changes of substance, i.e. tec

20、hnical enhancements, corrections, updates, etc. z the third digit is incremented when editorial only changes have been incorporated in the document. ETSI ETSI TS 138 422 V15.0.0 (2018-07)53GPP TS 38.422 version 15.0.0 Release 151 Scope The present document specifies the standards for signalling tran

21、sport to be used across Xn interface. The Xn interface provides means for interconnecting two NG-RAN nodes. The Xn interface is a logical interface between two nodes of the NG-RAN. The present document describes how the XnAP signalling messages are transported over Xn. 2 References The following doc

22、uments contain provisions which, through reference in this text, constitute provisions of the present document. - References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. - For a specific reference, subsequent revisions do not apply. -

23、 For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document. 1 3GPP TR 21.905: “Vocabulary for 3GPP S

24、pecifications“. 2 IETF RFC 4960: “Stream Control Transmission Protocol“. 3 3GPP TS 38.300: “NR; Overall Description; Stage 2“. 4 IETF RFC 2460 (1998-12): “Internet Protocol, Version 6 (IPv6) Specification“. 5 IETF RFC 791 (1981-09): “Internet Protocol“. 6 IETF RFC 2474 (1998-12): “Definition of the

25、Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers“. 3 Definitions and abbreviations 3.1 Definitions For the purposes of the present document, the terms and definitions given in 3GPP TR 21.905 1 and the following apply. A term defined in the present document takes precedence over

26、the definition of the same term, if any, in 3GPP TR 21.905 1. NG-RAN node: as defined in TS 38.300 3 Xn: interface between two NG-RAN nodes, providing an interconnection point between the NG-RAN nodes. Xn-C: Reference point for the control plane protocol between NG-RAN nodes. 3.2 Abbreviations For t

27、he purposes of the present document, the abbreviations given in 3GPP TR 21.905 1 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in 3GPP TR 21.905 1. IP Internet Protocol SCTP Stream Control Transmission

28、Protocol DiffServ Differentiated Service PPP Point to Point Protocol IANA Internet Assigned Number Authority ETSI ETSI TS 138 422 V15.0.0 (2018-07)63GPP TS 38.422 version 15.0.0 Release 154 Xn signalling bearer 4.1 Functions and protocol stack Xn-C signalling bearer provides the following functions:

29、 - Provision of reliable transfer of XnAP message over Xn-C interface. - Provision of networking and routeing function. - Provision of redundancy in the signalling network. - Support for flow control and congestion control. The protocol stack for Xn-C Signalling Bearer is shown in figure 4.1-1 and d

30、etails on each protocol are described in the following clauses. SCTP IP Data link layer XnAP Physical layer Radio Network Layer TransportNetworkLayer Figure 4.1-1: Xn-C signalling bearer protocol stack The Transport Network Layer is based on IP transport, comprising SCTP on top of IP. 5 Data link la

31、yer The support of any suitable Data Link Layer protocol, e.g. PPP, Ethernet, etc., shall not be prevented. 6 IP layer The NG-RAN node shall support IPv6 (IETF RFC 2460 4) and/or IPv4 (IETF RFC 791 5). The IP layer of Xn-C only supports point-to-point transmission for delivering XnAP message. The NG

32、-RAN node shall support the Diffserv Code Point marking as described in IETF RFC 2474 6. 7 Transport layer SCTP (IETF RFC 4960 2) shall be supported as the transport layer of Xn-C signalling bearer. The Payload Protocol Identifier assigned by IANA to be used by SCTP for the application layer protoco

33、l XnAP is 61. SCTP refers to the Stream Control Transmission Protocol developed by the Sigtran working group of the IETF for the purpose of transporting various signalling protocols over IP network. There shall be only one SCTP association established between two NG-RAN nodes. The SCTP Destination P

34、ort number value assigned by IANA to be used for XnAP is 38422. ETSI ETSI TS 138 422 V15.0.0 (2018-07)73GPP TS 38.422 version 15.0.0 Release 15Within the SCTP association established between one pair of two NG-RAN nodes: - a single pair of stream identifiers shall be reserved for the sole use of XnA

35、P elementary procedures that utilize non UE-associated signalling. - At least one pair of stream identifiers shall be reserved for the sole use of XnAP elementary procedures that utilize UE-associated signallings. However, a few pairs (i.e. more than one) should be reserved. - A single UE-associated

36、 signalling shall use one SCTP stream and the stream should not be changed during the communication of the UE-associated signalling. Transport network redundancy may be achieved by SCTP multi-homing between two end-points, of which one or both is assigned with multiple IP addresses. SCTP end-points

37、shall support a multi-homed remote SCTP end-point. For SCTP endpoint redundancy an INIT may be sent from one NG-RAN node, at any time for an already established SCTP association, which shall be handled as defined in IETF RFC 4960 2 in sub clause 5.2. The SCTP congestion control may, using an impleme

38、ntation specific mechanism, initiate higher layer protocols to reduce the signalling traffic at the source and prioritise certain messages. ETSI ETSI TS 138 422 V15.0.0 (2018-07)83GPP TS 38.422 version 15.0.0 Release 15Annex A (informative): Change history Change history Date Meeting TDoc CR Rev Cat

39、 Subject/Comment New version 2018-01 RAN3-AH-1801 R3-180544 Reflected agreed TP in RAN3-AH-1801 in 2018-01 (Sophia Antipolis) 0.2.0 2018-05 RAN3#100 R3-183596 Reflected agreed TP in RAN3#100 in 2018-05 (Busan) and made some editorial corrections 0.3.0 2018-06 RAN#80 RP-180682 Submitted to RAN plenar

40、y for Approval 1.0.0 2018-06 RAN#80 RP-181276 Typos corrected (“NGAP“ corrected to “XnAP“ in two places) 1.0.1 2018-06 RAN#80 - - - Specification approved at TSG-RAN and placed under change control 15.0.0 ETSI ETSI TS 138 422 V15.0.0 (2018-07)93GPP TS 38.422 version 15.0.0 Release 15History Document history V15.0.0 July 2018 Publication