ETSI TS 144 064 V6.3.0 (2012-01) Technical Specification Digital cellular telecommunications system (Phase 2+); Mobile Station - Serving GPRS Support Node (MS-SGSN); Logical Link Control (LLC) Layer Specification (3GPP TS 44.064 version 6.3.0 Release 6) R GLOBAL SYSTEM FOR MOBILE COMMUNICATIONS 3GPP TS 44.064 version 6.3.0 Release 6 1 ETSI TS 144 064 V6.3.0 (2012-01) Reference RTS/TSGC-0144064v630 Keywords GSM 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 à but non lucratif enregistrée à la Sous-Préfecture de Grasse (06) N° 7803/88 Important notice Individual copies of the present document can be downloaded from: http://www.etsi.org The present document may be made available in more than one electronic version or in print. In any case of existing or perceived difference in contents between such versions, the reference version is the Portable Document Format (PDF). 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ETSI 3GPP TS 44.064 version 6.3.0 Release 6 3 ETSI TS 144 064 V6.3.0 (2012-01) Contents Intellectual Property Rights ................................................................................................................................ 2 Foreword ............................................................................................................................................................. 2 Foreword ............................................................................................................................................................. 7 1 Scope ........................................................................................................................................................ 8 2 References ................................................................................................................................................ 9 3 Definitions and abbreviations ................................................................................................................. 10 3.1 Definitions ........................................................................................................................................................ 10 3.2 Abbreviations ................................................................................................................................................... 10 4 Overview description of LLC functions and procedures........................................................................ 11 4.1 Reference model ............................................................................................................................................... 12 4.2 General description of the LLC protocol .......................................................................................................... 12 4.2.1 Services required by the lower layers ......................................................................................................... 13 4.3 Unacknowledged operation .............................................................................................................................. 13 4.4 Acknowledged operation .................................................................................................................................. 13 4.5 Establishment of information transfer modes ................................................................................................... 13 4.5.1 Data link connection identification ............................................................................................................. 13 4.5.2 Logical link states ....................................................................................................................................... 14 4.5.3 TLLI assignment ......................................................................................................................................... 14 4.5.4 Establishment of ABM operation ............................................................................................................... 14 4.6 Data confidentiality .......................................................................................................................................... 14 4.7 LLC layer structure .......................................................................................................................................... 15 4.7.1 Logical Link Entity ..................................................................................................................................... 15 4.7.2 Multiplex procedure .................................................................................................................................... 16 4.7.3 Logical Link Management .......................................................................................................................... 16 4.8 GPRS Mobility Management ........................................................................................................................... 16 4.9 Short Message Service ..................................................................................................................................... 16 4.10 Tunnelling Of Messages ................................................................................................................................... 16 5 Frame structure ....................................................................................................................................... 16 5.1 General ............................................................................................................................................................. 16 5.2 Address field .................................................................................................................................................... 17 5.3 Control field ..................................................................................................................................................... 17 5.4 Information field .............................................................................................................................................. 17 5.5 Frame Check Sequence (FCS) field ................................................................................................................. 17 5.6 Transparency .................................................................................................................................................... 18 5.6.1 Bit transparency .......................................................................................................................................... 18 5.6.2 Information protection ................................................................................................................................ 18 5.6.3 Octet alignment ........................................................................................................................................... 18 5.7 Format convention ............................................................................................................................................ 18 5.7.1 Numbering convention ............................................................................................................................... 18 5.7.2 Order of transmission.................................................................................................................................. 19 5.7.3 Field mapping convention .......................................................................................................................... 19 5.8 Invalid frames ................................................................................................................................................... 19 6 Elements of procedures and formats of fields ........................................................................................ 19 6.1 General ............................................................................................................................................................. 19 6.2 Address field format and variables ................................................................................................................... 20 6.2.1 Protocol Discriminator bit (PD) .................................................................................................................. 20 6.2.2 Command/Response bit (C/R) .................................................................................................................... 20 6.2.3 Service Access Point Identifier (SAPI) ....................................................................................................... 20 6.3 Control field formats, parameters, and variables .............................................................................................. 21 6.3.1 Information transfer format - I .................................................................................................................... 23 6.3.2 Supervisory format - S ................................................................................................................................ 23 6.3.3 Unconfirmed Information format - UI ........................................................................................................ 23 ETSI 3GPP TS 44.064 version 6.3.0 Release 6 4 ETSI TS 144 064 V6.3.0 (2012-01) 6.3.4 Unnumbered format - U .............................................................................................................................. 23 6.3.5 Control field parameters and associated state variables .............................................................................. 23 6.3.5.1 Poll/Final bit (P/F) ................................................................................................................................ 23 6.3.5.2 Acknowledgement request bit (A) ........................................................................................................ 23 6.3.5.3 Modulus ................................................................................................................................................ 24 6.3.5.4 ABM variables and sequence numbers ................................................................................................. 24 6.3.5.4.1 Send state variable V(S) .................................................................................................................. 24 6.3.5.4.2 Acknowledge state variable V(A) ................................................................................................... 24 6.3.5.4.3 Send sequence number N(S) ............................................................................................................ 24 6.3.5.4.4 Receive state variable V(R) ............................................................................................................. 24 6.3.5.4.5 Receive sequence number N(R) ...................................................................................................... 24 6.3.5.4.6 SACK bitmap R(n) .......................................................................................................................... 25 6.3.5.4.7 I frame buffer variable B ................................................................................................................. 25 6.3.5.4.8 Other parameters and variables ....................................................................................................... 25 6.3.5.5 Unacknowledged operation variables and parameters .......................................................................... 25 6.3.5.5.1 Encryption mode bit (E) .................................................................................................................. 25 6.3.5.5.2 Protected Mode bit (PM) ................................................................................................................. 25 6.3.5.5.3 Unconfirmed send state variable V(U) ............................................................................................ 26 6.3.5.5.4 Unconfirmed sequence number N(U) .............................................................................................. 26 6.3.5.5.5 Unconfirmed receive state variable V(UR) ..................................................................................... 26 6.3.5.5.6 Other parameters and variables ....................................................................................................... 26 6.4 Commands and responses ................................................................................................................................ 26 6.4.1 Unnumbered (U) frames ............................................................................................................................. 26 6.4.1.1 Set Asynchronous Balanced Mode (SABM) command ........................................................................ 26 6.4.1.2 Disconnect (DISC) command ............................................................................................................... 27 6.4.1.3 Unnumbered Acknowledgement (UA) response................................................................................... 27 6.4.1.4 Disconnected Mode (DM) response ...................................................................................................... 27 6.4.1.5 Frame Reject (FRMR) response ............................................................................................................ 27 6.4.1.6 Exchange Identification (XID) command/response .............................................................................. 28 6.4.1.7 NULL command ................................................................................................................................... 31 6.4.2 Unconfirmed Information (UI) frame ......................................................................................................... 31 6.4.2.1 Unconfirmed Information (UI) command ............................................................................................. 31 6.4.2.2 Unconfirmed Information (UI) Dummy command ............................................................................... 31 6.4.3 Combined Information (I) and Supervisory (S) frames .............................................................................. 31 6.4.3.1 Receive Ready (RR) command / response ............................................................................................ 32 6.4.3.2 Acknowledgement (ACK) command / response ................................................................................... 32 6.4.3.3 Selective Acknowledgement (SACK) command / response ................................................................. 32 6.4.3.4 Receive Not Ready (RNR) command / response .................................................................................. 32 7 Elements for layer-to-layer communication ........................................................................................... 32 7.1 Definition of service primitives and parameters ............................................................................................... 32 7.1.1 Primitives types .......................................................................................................................................... 33 7.1.1.1 Request .................................................................................................................................................. 33 7.1.1.2 Indication .............................................................................................................................................. 33 7.1.1.3 Response ............................................................................................................................................... 33 7.1.1.4 Confirm ................................................................................................................................................. 33 7.1.2 LLC layer service primitives ...................................................................................................................... 33 7.2 Primitive procedures......................................................................................................................................... 34 7.2.1 GMM - LLME primitives ........................................................................................................................... 34 7.2.1.1 LLGMM-ASSIGN ................................................................................................................................ 34 7.2.1.2 LLGMM-RESET .................................................................................................................................. 35 7.2.1.3 LLGMM-TRIGGER ............................................................................................................................. 35 7.2.1.4 LLGMM-SUSPEND ............................................................................................................................. 35 7.2.1.5 LLGMM-RESUME .............................................................................................................................. 36 7.2.1.6 LLGMM-PAGE .................................................................................................................................... 36 7.2.1.7 LLGMM-IOV ....................................................................................................................................... 36 7.2.1.8 LLGMM-STATUS ............................................................................................................................... 36 7.2.1.9 LLGMM-PSHO .................................................................................................................................... 36 7.2.2 Layer 3 - LLE primitives ............................................................................................................................ 36 7.2.2.1 LL-RESET ............................................................................................................................................ 36 7.2.2.2 LL-ESTABLISH ................................................................................................................................... 37 7.2.2.3 LL-RELEASE ....................................................................................................................................... 37 ETSI 3GPP TS 44.064 version 6.3.0 Release 6 5 ETSI TS 144 064 V6.3.0 (2012-01) 7.2.2.4 LL-XID ................................................................................................................................................. 37 7.2.2.5 LL-DATA ............................................................................................................................................. 37 7.2.2.6 LL-UNITDATA .................................................................................................................................... 37 7.2.2.7 LL-STATUS ......................................................................................................................................... 37 7.2.3 LLE - RLC/MAC primitives ....................................................................................................................... 37 7.2.3.1 GRR-DATA .......................................................................................................................................... 37 7.2.3.2 GRR-UNITDATA ................................................................................................................................ 38 7.2.4 LLE - BSSGP primitives ............................................................................................................................ 38 7.2.4.1 BSSGP-DL-UNITDATA ...................................................................................................................... 38 7.2.4.2 BSSGP-UL-UNITDATA ...................................................................................................................... 38 7.2.5 LLME - LLE primitives .............................................................................................................................. 38 8 Definition of the LLC peer-to-peer protocol .......................................................................................... 38 8.1 General ............................................................................................................................................................. 38 8.2 Procedure for the use of the P/F bit .................................................................................................................. 39 8.3 TLLI assignment procedures ............................................................................................................................ 39 8.3.1 TLLI assignment ......................................................................................................................................... 39 8.3.2 TLLI change ............................................................................................................................................... 40 8.3.3 TLLI unassignment ..................................................................................................................................... 40 8.4 Procedures for unacknowledged information transfer ...................................................................................... 40 8.4.1 Transmission of unacknowledged information ........................................................................................... 40 8.4.2 Receipt of unacknowledged information .................................................................................................... 40 8.5 Procedures for establishment and release of ABM operation ........................................................................... 41 8.5.1 Establishment of ABM operation ............................................................................................................... 41 8.5.1.1 General .................................................................................................................................................. 41 8.5.1.2 Establishment procedures ...................................................................................................................... 41 8.5.1.3 Procedure on expiry of timer T200 ....................................................................................................... 42 8.5.2 Termination of ABM operation .................................................................................................................. 42 8.5.2.1 General .................................................................................................................................................. 42 8.5.2.2 Release procedure ................................................................................................................................. 43 8.5.2.3 Procedure on expiry of timer T200 ....................................................................................................... 43 8.5.3 Automatic negotiation of LLC layer and layer-3 parameters ..................................................................... 43 8.5.3.1 Negotiation of parameter Reset ............................................................................................................. 44 8.5.3.2 Negotiation of parameter m................................................................................................................... 45 8.5.3.3 Unsuccessful XID negotiation .............................................................................................................. 45 8.5.3.4 Procedure on expiry of timer T200 ....................................................................................................... 46 8.5.4 TLLI Assigned / ADM state ....................................................................................................................... 46 8.5.5 Collision of unnumbered commands .......................................................................................................... 46 8.5.5.1 Identical transmitted and received commands ...................................................................................... 47 8.5.5.2 Different transmitted and received commands ...................................................................................... 47 8.5.6 Unsolicited DM response and SABM or DISC command .......................................................................... 47 8.6 Procedures for information transfer in ABM operation.................................................................................... 48 8.6.1 Transmitting I frames.................................................................................................................................. 48 8.6.2 Receiving I frames ...................................................................................................................................... 49 8.6.3 Sending and receiving acknowledgements ................................................................................................. 49 8.6.3.1 Sending acknowledgements .................................................................................................................. 49 8.6.3.2 Receiving acknowledgements ............................................................................................................... 50 8.6.3.3 Requesting acknowledgements ............................................................................................................. 50 8.6.4 Peer receiver busy condition ....................................................................................................................... 50 8.6.4.1 Supervisory frame selection .................................................................................................................. 51 8.6.5 Own receiver busy condition ...................................................................................................................... 51 8.6.6 Waiting for acknowledgement .................................................................................................................... 51 8.7 Re-establishment of ABM operation ................................................................................................................ 52 8.7.1 Criteria for re-establishment ....................................................................................................................... 52 8.7.2 Procedures................................................................................................................................................... 52 8.8 Exception condition reporting and recovery .................................................................................................... 52 8.8.1 Invalid frame condition ............................................................................................................................... 52 8.8.2 Frame rejection condition ........................................................................................................................... 53 8.8.3 Receipt of a FRMR response frame ............................................................................................................ 53 8.8.4 Unsolicited response frames ....................................................................................................................... 53 8.9 List of LLC layer parameters ........................................................................................................................... 53 8.9.1 LLC version number (Version) ................................................................................................................... 54 ETSI 3GPP TS 44.064 version 6.3.0 Release 6 6 ETSI TS 144 064 V6.3.0 (2012-01) 8.9.2 Input Offset Value (IOV) ............................................................................................................................ 54 8.9.3 Retransmission timers (T200 and T201) ..................................................................................................... 54 8.9.4 Maximum number of retransmissions (N200) ............................................................................................ 54 8.9.5 Maximum number of octets in an information field (N201) ....................................................................... 54 8.9.6 Maximum number of octets in the layer-3 header (N202) .......................................................................... 54 8.9.7 Maximum I frame buffer size (m) .............................................................................................................. 54 8.9.8 Maximum number of outstanding I frames (k) ........................................................................................... 55 8.9.9 LLC layer parameter default values ............................................................................................................ 55 Annex A (normative): Ciphering ........................................................................................................ 56 A.1 General ................................................................................................................................................... 56 A.2 Ciphering algorithm interface ................................................................................................................ 56 A.2.1 Generation of Input .......................................................................................................................................... 57 Annex B (normative): Tunnelling of Messages (TOM) .................................................................... 58 B.1 TOM Protocol Envelope structure ......................................................................................................... 58 B.1.1 TOM Protocol Discriminator ........................................................................................................................... 58 B.1.2 Remaining Length of TOM Protocol Header ................................................................................................... 59 B.1.3 Remaining Octets of TOM Protocol Header .................................................................................................... 59 B.1.4 Message Capsule .............................................................................................................................................. 59 Annex C (informative): LLC layer states for peer-to-peer operation ............................................... 60 C.1 General ................................................................................................................................................... 60 C.2 An overview of the peer-to-peer LLC layer states ................................................................................. 60 Annex D (informative): Change history ............................................................................................... 62 History .............................................................................................................................................................. 63 ETSI 3GPP TS 44.064 version 6.3.0 Release 6 7 ETSI TS 144 064 V6.3.0 (2012-01) Foreword This Technical Specification has been produced by the 3rd Generation 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 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. technical enhancements, corrections, updates, etc. z the third digit is incremented when editorial only changes have been incorporated in the document. ETSI 3GPP TS 44.064 version 6.3.0 Release 6 8 ETSI TS 144 064 V6.3.0 (2012-01) 1 Scope The present document defines the Logical Link Control (LLC) layer protocol to be used for packet data transfer between the Mobile Station (MS) and Serving GPRS Support Node (SGSN). It defines the frame structure, elements of procedure, format of fields, and procedures for the proper operation of the logical link control layer. It is based on ideas contained in IS-130 [21], ISO 3309 [16], ISO 4335 [17], and ISO 7809 [18, 19, 20] (HDLC of ISO), as well ITU-T Q.920 [13] and Q.921 [14] (LAPD). The concepts, the overview description of LLC layer functions and procedures, and the relationship with other Technical Specifications are described in general terms in 3GPP TS 23.060 [5]. LLC spans from the Mobile Station (MS) to the Serving GPRS Support Node (SGSN). LLC is intended for use with both acknowledged and unacknowledged data transfer. The frame formats defined for LLC are based on those defined for LAPD and RLP. However, there are important differences between LLC and other protocols, in particular with regard to frame delimitation methods and transparency mechanisms. These differences are necessary for independence from the radio path. The LLC procedures are modelled upon the concepts of HDLC as outlined in ISO 4335. Data sequence integrity between the data source and data sink is effected by means of a cyclic numbering scheme. An independent numbering scheme is used for each logical data link, as identified by the a data link connection identifier. LLC supports two modes of operation: - Unacknowledged peer-to-peer operation: A logical link entity may initiate transmissions to a peer entity without prior establishment of a logical connection with the peer entity. LLC does not guarantee in-order delivery. LLC can detect errors in a received frame, and, depending on whether the frame is sent in protected mode or not, either discard or deliver the erroneous frame. No error recovery procedures are defined at the LLC layer. Higher-layer protocols can be used to provide reliability, if needed. This mode of operation is known as Asynchronous Disconnected Mode (ADM). - Acknowledged peer-to-peer operation: A balanced data link involves two participating entities, and each entity assumes responsibility for the organisation of its data flow and for error recovery procedures associated with the transmissions that it originates. Each entity operates as both a data source and data sink in a balanced link, allowing information to flow in both directions. This mode of operation is known as Asynchronous Balanced Mode (ABM), and provides a reliable service with in-order delivery. The present document is organised as follows: - An overview of the LLC layer functions is given in clause 4. - The frame structure for peer-to-peer communication is given in clause 5. - The elements of procedure and formats of fields are given in clause 6. - The elements of layer-to-layer communication are contained in clause 7. - The details of the peer-to-peer ABM procedures are given in clause 8. - The details of LLC frame ciphering are given in annex A. - The details of the TOM protocol layer are contained in annex B. - An overview of the LLC layer states is provided in annex C. ETSI 3GPP TS 44.064 version 6.3.0 Release 6 9 ETSI TS 144 064 V6.3.0 (2012-01) 2 References The following documents 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. • 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 Specifications". [2] 3GPP TS 41.061: "General Packet Radio Service (GPRS); GPRS ciphering algorithm requirements". [3] 3GPP TS 22.060: "General Packet Radio Service (GPRS); Service description; Stage 1". [4] 3GPP TS 23.040: "Technical realization of the Short Message Service (SMS); Point-to-Point (PP)". [5] 3GPP TS 23.060: "General Packet Radio Service (GPRS); Service description; Stage 2". [6] 3GPP TS 43.064: "General Packet Radio Service (GPRS); Overall description of the GPRS radio interface; Stage 2". [7] 3GPP TS 44.001: "Mobile Station - Base Station System (MS - BSS) interface; General aspects and principles". [8] 3GPP TS 44.018: "Mobile radio interface; Layer 3 specification; Radio Resource Control Protocol". [8a] 3GPP TS 24.008: "Mobile radio interface layer 3 specification; Core Network Protocols; Stage 3". [9] 3GPP TS 24.011: "Point-to-Point (PP) Short Message Service (SMS) support on mobile radio interface". [10] 3GPP TS 24.022: "Radio Link Protocol (RLP) for circuit switched bearer and teleservices". [11] 3GPP TS 44.065: "General Packet Radio Service (GPRS); Mobile Station (MS) – Serving GPRS Support Node (SGSN); Subnetwork Dependent Convergence Protocol (SNDCP)". [12] 3GPP TS 48.018: "General Packet Radio Service (GPRS); Base Station System (BSS) - Serving GPRS Support Node (SGSN); BSS GPRS Protocol (BSSGP)". [13] ITU-T Recommendation Q.920 (1988): "ISDN user-network interface data link layer - General aspects". [14] ITU-T Recommendation Q.921 (1988): "ISDN user-network interface - Data link layer specification". [15] ITU-T Recommendation Z.100 (1988): "CCITT specification and description language (SDL)". [16] ISO 3309 (1984): "Information processing systems - Data communications - High-level data link control procedure - Frame structure". [17] ISO 4335 (1987): "Information processing systems – Data communication – High-level logical link control procedures – Consolidation of elements of procedures". [18] ISO 7809 (1984): "Information processing systems – Data communication – High-level logical link control procedures – Consolidation of classes of procedures". ETSI