1、 ETSI TS 125 462 V14.0.0 (2017-04) Universal Mobile Telecommunications System (UMTS); UTRAN Iuant interface: Signalling transport (3GPP TS 25.462 version 14.0.0 Release 14) TECHNICAL SPECIFICATION ETSI ETSI TS 125 462 V14.0.0 (2017-04)13GPP TS 25.462 version 14.0.0 Release 14Reference RTS/TSGR-03254
2、62ve00 Keywords UMTS 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 document can b
3、e downloaded from: http:/www.etsi.org/standards-search 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
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7、ut the written authorization of ETSI. The copyright and the foregoing restriction extend to reproduction in all media. European Telecommunications Standards Institute 2017. All rights reserved. DECTTM, PLUGTESTSTM, UMTSTMand the ETSI logo are Trade Marks of ETSI registered for the benefit of its Mem
8、bers. 3GPPTM and LTE are 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 TS 125 462 V14.0.0 (2017-04)23GPP TS 25.462 version 14.0.0 Release 14Intellectua
9、l 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 (IP
10、Rs); 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 (https:/ipr.etsi.org/). Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been
11、 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 3rd
12、 Generation Partnership Project (3GPP). The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or GSM identities. These should be interpreted as being references to the corresponding ETSI deliverables. The cross reference between GSM, UMTS,
13、 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“, “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 D
14、rafting Rules (Verbal forms for the expression of provisions). “must“ and “must not“ are NOT allowed in ETSI deliverables except when used in direct citation. ETSI ETSI TS 125 462 V14.0.0 (2017-04)33GPP TS 25.462 version 14.0.0 Release 14Contents Intellectual Property Rights 2g3Foreword . 2g3Modal v
15、erbs terminology 2g3Foreword . 5g31 Scope 6g32 References 6g33 Definitions and abbreviations . 6g33.1 Definitions 6g33.2 Abbreviations . 7g34 Iuant data link layer 7g34.1 Invalid receptions . 7g34.2 Frame lengths . 7g34.3 Default address . 7g34.4 Window size . 8g34.5 Message timing 8g34.6 State mode
16、l . 8g34.7 Device types . 8g34.8 XID negotiation 9g34.8.1 HDLC parameters . 9g34.8.2 Protocol version 9g34.8.3 Address assignment 9g34.8.4 Device scan . 10g34.8.5 Reset device 10g34.9 Link establishment . 10g34.10 Link timeout . 11g3Annex A (informative): HDLC description 12g3A.1 Basic structure 12g
17、3A.2 UNC commands . 13g3A.2.1 Set Normal Response Mode (SNRM) . 13g3A.2.2 Disconnect (DISC) 13g3A.2.3 Unnumbered Acknowledge (UA) . 13g3A.2.4 Disconnected Mode (DM) 13g3A.2.5 Receiver Ready (RR) 13g3A.2.6 Receiver Not Ready (RNR) 13g3A.2.7 Information (I) 13g3A.2.8 Frame Reject (FRMR) 13g3A.3 Option
18、 1 14g3A.4 Option 4 14g3A.5 Option 15.1 . 14g3A.6 Link safety 14g3A.7 Full duplex link 14g3Annex B (informative): HDLC parameter negotiation . 16g3Annex C (informative): HDLC parameter negotiation example 17g3Annex D (informative): Address assignment example 18g3D.1 Address assignment command 18g3D.
19、2 Address assignment response . 19g3Annex E (informative): Device scan example 20g3Annex F (informative): Change History 22g3ETSI ETSI TS 125 462 V14.0.0 (2017-04)43GPP TS 25.462 version 14.0.0 Release 14History 23g3ETSI ETSI TS 125 462 V14.0.0 (2017-04)53GPP TS 25.462 version 14.0.0 Release 14Forew
20、ord This Technical Specification has been produced by the 3rdGeneration 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
21、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
22、 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 ETSI TS 125 462 V14.0.0 (2017-04)63GPP TS 25.462 version 14.0.0 Release 141 Scope The
23、present document specifies the signalling transport related to RETAP and TMAAP signalling to be used across the Iuant interface. The logical Iuant interface is a Node B/eNB internal interface between the implementation specific O - The “U” means Unbalanced operation (master slave operation); - The “
24、N” means Normal response mode (sequence numbers used in data frames); - The “C” means Class. - Options supported; - “1” means use of XID negotiation; - “15.1” means use of start/stop transmission with basic transparency; - Two Way Alternate (TWA) is the HDLC term for half duplex. A.1 Basic structure
25、 In unbalanced operation, there is one primary station (master) which controls the bus and a number of secondary stations (slaves) which only are allowed to transmit when the primary station gives them permission to do so. All messages are transmitted as frames with the layout shown in table A.1.1:
26、Table A.1.1: Format of an HDLC frame Flag 1 octet ADDR 1 octet Control 1 octet INFO N octets FCS 2 octets Flag 1 octet 0x7E Secondary Station Address Control bits Variable length CRC 0x7E HDLC frames begin and end with a Flag (0x7E) (see A.5 for details). The transmitting station calculates a Frame
27、Check Sequence (CRC16) on all octets which follow the starting flag but not including the FCS octets. The checksum is transmitted as FCS in little endian order and is followed by the closing flag. The receiving station calculates the checksum on all octets between the flags. When it finds the closin
28、g flag, it compares the checksum to 0xF0B8. If it is a match, the HDLC frame is processed. The address field contains the HDLC address of the secondary station. If the primary station sends the message, it is called a command and the address field contains the address of the secondary station as des
29、tination. If the secondary station sends the message, it is called a response and the address field contains the address of the secondary station as source. Secondary stations cannot communicate directly to each other. The control field defines one of three frame types: - I frames contain data as we
30、ll as a send and receive counter; - S frames contain a receive counter; - U frames contain unnumbered commands. The INFO field is only present in I frames and XID frames. The INFO field in an I frame contains the layer 7 payload. ETSI ETSI TS 125 462 V14.0.0 (2017-04)133GPP TS 25.462 version 14.0.0
31、Release 14A.2 UNC commands According to 6.6.2.1 in ISO/IEC 13239 2 the following commands in shall be supported in UNC mode: Table A.2.1: Commands supported in UNC mode Commands (Primary Station) Responses (Secondary Station) Frame type I Frame type I Frame type RR Frame type RR Frame type RNR Frame
32、 type RNR Frame type SNRM Frame type UA Frame type DISC Frame type DM Frame ty FRMRA.2.1 Set Normal Response Mode (SNRM) This command is used to set the secondary station in connected mode and reset its sequence number variables. A.2.2 Disconnect (DISC) This command is used to terminate the connecti
33、on. A.2.3 Unnumbered Acknowledge (UA) This response is used to confirm that the secondary station received and acted on an SNRM or DISC command. A.2.4 Disconnected Mode (DM) This response is used to inform the primary station that the secondary station is disconnected. A.2.5 Receiver Ready (RR) This
34、 command and response is used to inform the opposite station (primary or secondary) that the transmitting station has empty buffers, i.e. is ready to receive an I frame. This aspect is used for flow control. It also contains the sequence number of the next frame the transmitting station expects to s
35、ee. This works both as an ACK and a NAK depending on the value. A.2.6 Receiver Not Ready (RNR) Just like RR, except it informs the opposite station that the transmitting station does not have empty buffers, i.e. that it is not ready to receive an I frame. This aspect is used for flow control. A.2.7
36、Information (I) This command and response is used to transfer a block of data together with its sequence number. The command also includes the sequence number of the next frame the transmitting station expects to see. This way, it works as an RR. Like RR, it enables transmission of I frames from the
37、 opposite side. A.2.8 Frame Reject (FRMR) This response is used to indicate an error condition. The two most likely error conditions are: - Invalid command; - Sequence number problem. ETSI ETSI TS 125 462 V14.0.0 (2017-04)143GPP TS 25.462 version 14.0.0 Release 14The latter is used when the primary
38、station has requested retransmission of a sequence number which it has already acknowledged. A.3 Option 1 Option 1 means the addition of the XID command/response, which is used for parameter negotiation. A.4 Option 4 Option 4 means the addition of the UI command/response, which is used to transfer i
39、nformation without changing the sequence numbers used by I frames. A.5 Option 15.1 Option 15.1 means that the serial link is not synchronous and start/stop flags are used (asynchronous serial link). The flags are coded as 0x7E and basic transparency is used. This means that all octets between the fl
40、ags are part of the frame and shall not be transmitted as 0x7E. Since the frame may contain 0x7E, basic transparency is used, which means that 0x7E is transmitted as 0x7D 0x5E and 0x7D is transmitted as 0x7D 0x5D. The receiving station converts back on reception. All checksum calculations are done o
41、n unconverted data. A.6 Link safety HDLC provides the upper layer with a safe link between two stations. Unless excessive frame lengths are used, the CRC16 checksum provides excellent protection against transmission errors. At worst, 105of the bit errors will not be detected. The likelihood of an un
42、detected error in a frame can be calculated by multiplying 105with the Bit Error Rate (at least 109for a reasonable link) and the frame length. The sequence numbers provide protection against: - Message duplication; - Message deletion; - Message re-ordering. Without sequence numbers, the protection
43、is only given by a checksum and some sort of ACK. If the original message is lost, there will be no ACK and a timeout will cause retransmission which solves the problem. If the original message is not lost, but the ACK is lost, the same timeout will cause a retransmission. With sequence numbers, the
44、 message is retransmitted, but the receiving station sees that the sequence number is the same, i.e. that the message is a retransmission, and throws it away without processing it further. It does send an ACK which informs the transmitting station that the message got through. A.7 Full duplex link T
45、he upper layer sees the HDLC link as a full duplex link, although the actual transmissions on layer 1 are half duplex. The reason for this is that the upper layer is not aware of any restrictions on transmissions or receptions between layer 2 and layer 1 or between the stations. Whenever the upper l
46、ayer wants to transmit, it places a message on the queue to layer 2. The message will not be transmitted until the primary station does a poll. NOTE: This applies to both the primary and the secondary station. ETSI ETSI TS 125 462 V14.0.0 (2017-04)153GPP TS 25.462 version 14.0.0 Release 14The same a
47、pplies to reception. The upper layer will either be told by layer 2 when a message has arrived, or it will periodically check to see if a message has arrived at layer 2. Neither of these two methods will in any way influence the reception of a message. That only depends on when the primary does a po
48、ll. NOTE This still applies to both the primary and the secondary station. A poll is a command frame from the primary station where the P/F (Poll/Final) bit in the control field is set to 1. This informs the secondary that it is allowed to transmit response frames. U frames set the P/F bit, which me
49、ans that they are polls. However, since the U frames used in UNC 1,4 require a specific U frame response, they are not used for I frame transmission, which is what the upper layer messages depend upon. An I, RR or RNR frame type with the P/F bit set constitutes a poll as used above. An RNR frame prevents transmission of I frames, so it does not really apply. NOTE: Whenever an I or RR poll occurs, the secondary station may transmit whatever I frame it wishes (as long as the window size is not exceeded, i.e. previous messages have been acknowledged). This means that the se
