1、CEPT T/S*4b-30*E m 232b41ii 0008bb2 8 m Page 1 (Old reference: T/CS 46-30) Recommendation T/S 46-30 (T/GSI 04-02/3) (Nice 1985, revised in Copenhagen 1987) ISDN USER-NETWORK INTERFACE LAYER 3 SPECIFICATION APPLICATION OF CCITT RECOMMENDATIONS Q.930/1.450 AND Q.931/1.451 Recommendation prepared by Wo
2、rking Group T/WG 1 1 “Signalling, Protocols and Switching” (SPS) Text of the Recommendation adopted by the “Telecommunications” Commission. “The European Conference of Postal and Telecommunications Administrations, considering - that CCITT Recommendations Q.930iI.450 and Q.93111.45 1 define the ISDN
3、 User-Network interface Layer 3, - that there are a number of options and points requiring further specification in Recommendations Q.930/1.450 - that the harmonization of the ISDN User-Network Interface is an important requirement for European Adminis- and Q.931ii.451, trations, O recommends that E
4、uropean Administrations who wish to provide ISDN services apply the CCITT Recommendations Q.930/1.450 and Q.93111.451 in accordance with the specification defined below.” INTRODUCTION This Recommendation is a revised version of CEPT Recommendation T/CS 46-30 (Nice 1985) i. It is based on the revisio
5、ns to CCITT Recommendation(s) Q.931/1.451 2 which have been made by the CCITT 1985-87. it includes those elements of Q.931 that are considered to be stable and applicable to Europe. The Recommendation also provides additional specification text for the harmonization of the ISDN User-Network interfac
6、e within Europe. All procedures at the User-Network Interface apply to both the S and T Reference Points. CCITT Recommendation Q.930/1.450 3 applies without modifications and is not reproduced in this Recommen- dation. The layout of this Recommendation is aligned with the layout of the draft revisio
7、n to CCITT Recommendation(s) 4.931. However, the numbering of paragraphs, figures and tables are not identical to that of the CCITT version. Notes inserted for explanatory purposes are encircled by asterisks. O Edition of September 15, 1988 CEPT T/S*4b-30*E 2326414 0008bb3 T TIS 46-30 E Page 2 Conte
8、nts of Recommendation T/S 46-30 1 . GENERAL . 3 1 .l. Scope of the Recommendation . 3 1.2. Application to interface structures 3 2 OVERVIEW OF CALL CONTROL 3 2.1. Circuit-switched calls . 3 2.2. Packet mode calls . 7 2.3. Other network services 7 3 . MESSAGE FUNCTIONAL DEFINITIONS AND CONTENT . 7 Pa
9、ge 1 I . 3.1. Messages for circuit mode connections 9 3.2. Messages for packet mode connections 29 4 . GENERALMESSAGEFORMATANDINFORMATIONELEMENTCODING 30 4.1. Overview 30 4.2. Protocol discriminator . 31 4.3. Callreference 32 4.4. Message type 33 4.5. Other information elements . 34 5 . 5.1. 5.2. 5.
10、3. 5.4. 5.5. 5.6. 5.7. 5.8. 5.9. CIRCUIT-SWITCHED CALL CONTROL PROCEDURES Call establishment at the originating interface . Call establishment at the destination interface . In-band tones and announcements Call clearing . Restart procedures Call rearrangements Call collisions Procedures for user-to-
11、user signalling associated to circuit switched calls . Handling of error conditions 83 83 88 93 97 98 98 101 101 104 6 . PROCEDURES FOR PACKET COMMUNICATION 107 7 . PROCEDURES FOR SUPPLEMENTARY SERVICES . 107 7.1. Closed user group . 107 7.2. Direct dialng in (DDI) 116 7.3. Calling line identificati
12、on 116 7.4. Called line identification 118 7.5. Subaddressing 118 8 . LIST OF SYSTEM PARAMETERS 120 8.1. Timers at the network side . 120 8.2. Timers at the user side . 120 ANNEXES Annex 1 . Annex 2 . Annex 3 . Annex 4 . Annex 5 . Annex 6 . Annex 7 . Annex 8 . Coding of Bearer Capability Information
13、 Element Definition of causes . Examples of the use of the Charge Advice information element Formats and coding of facility information within Keypad information elements Examples of possible use of the Date/time information element Extensions for symmetric call establishment . Called Line identific
14、ation supplementary service . Compatibility checking 125 129 137 139 140 147 144 146 Edition of September 15. 1988 CEPT T/S*46-30*E D 2326414 0008bb4 L D TIS 46-30 E Page 3 1. GENERAL This Recommendation specifies the procedures for the establishing, maintaining and clearing of network connections a
15、t the ISDN user-network interface. These procedures are defined in terms of messages exchanged over the D-channel of basic and primary rate interface structures defined in CCITT Recommen- dation 1.412 4. The functions and procedures of this protocol, and the relationship with other layers, are descr
16、ibed in general terms in CCITT Recommendation 4.930 (1.450) 3. Note. It is intended that this Recommendation will specify the essential features, procedures and messages required for call control in the D-channel. However, there are some dctails of procedure which have not yet been specified, and wh
17、ich will be the subject of further study. The attention of implementors is drawn to the fact that many call related facilities are not currently supported by the services of the OS1 Network Layer as defined in CCITT Recommendation X.213. Consideration of whether the signalling protocol supporting su
18、ch facilities should be implemented as network layer (OS1 layer 3) or application layer (OS1 layer 7) is a subject for further study. Resolution of this matter may impact the layering of the protocol defined in CCITT Recommendation 4.931. 1.1. Scope of the Recommendation The procedures currently des
19、cribed in this Recommendation are for the control of circuit-switched connec- tions (paragraph 5.) and packet-switched connection (paragraph 6.). User-to-user signalling connection and the carriage of other message-based information flows (telemetry, etc.) on the D-channel is a subject for further s
20、tudy and will be included in later versions of this Recommendation. Procedures for supplementary services are contained in paragraph 7. Note. The term “layer 3” is used for the functions and protocol described in this Recommendation (see paragraph 1 of CCITT Recommendation Q.930 (1.450) 3). Alignmen
21、t of the functions and protocols with those of OS1 network layer is for further study. The terms “data link layer” and “layer 2” are used interchangeably to refer to the layer immediately below layer 3. 1.2. Application to interface structures The layer 3 procedures apply to the interface structures
22、 defined in CCITT Recommendation 1.412 4. They use all of the functions and services provided by layer 2 with the exception of the unacknowledged information transfer service which is used only on basic access interface structures to provide point-to-multi- point operation at layer 3. 2. OVERVIEW OF
23、 CALL CONTROL In this Recommendation the terms “incoming” and “outgoing” are used to describe the call as viewed by the user side of the interface. 2.1. Circuit-switched calls This section provides the definition for states that individual calls may have. These definitions do not apply to the state
24、of the interface itself, any attached equipment, the D-channel, or the logical links used for signalling on the D-channel and do not apply to the state of the call reference. They are call states. Because several calls may exist simultaneously at a user-network interface, and each call may be in a d
25、ifferent state, the state of the interface itself cannot be unambiguously defined. Detailed description of the procedures for circuit-switched call control are given in paragraph 5. In terms of the sequence of messages defined in paragraph 3. which are transferred across the user-network interface,
26、and the information processing and actions that take place in the terminal and the exchange in the process of call establishment and clearing. An example of a procedure for a simple circuit switched call is shown in Figure 1 (T/S 46-30). Throughout this Recommendation, reference to B-channels is mad
27、e as far as circuit-swiched calls are concerned. The application of the call control procedures defined in this Recommendation to other channel types is not excluded. Further study on extending the application to other channel types is needed. . * * No SDL diagrams (overview or detailed) are include
28、d in this issue of the Recommendation. . $ $ Friitinn nf September 15, 1988 CEPT T/S*46-30*E 2326434 0008665 3 T/S 46-30 E Page 4 1 l I 1 I I I I I I I I I I 1 I I I I I I 7 Note 1. The sequence for overlap sending is nc represented in this diagram. Note 2. A terminal should not release the D-channe
29、l connection and power until after this point. Note 3. A proposal for further study (it may be a national matter). Note 4. Proposed switch-through points and the sequence in which they occur. Note 5. Proposed network release points and sequence. Note 6. The interactions between the human and the ter
30、minal are shown for illustration only. Figure 1 (T/S 46-30). Procedure for a simple circuit-switched call (example). Edition of September 15, 1988 CEPT T/S*4b-30*E 232b414 0008bbb 5 2.1.1 2.1.1.1. 2.1.1.2. 2.1 .I .3. 2.1.1.4. 2.1.1.5. 2.1.1.6. 2.1.1.7. 2.1.1.8. 2.1.1.9. TIS 46-30 E Page 5 Cull state
31、s ut the user side of the interface The states which may exist on the user side of the user-network interface are defined in this section. Note. All states are CCITT defined states except states U13 and U14 which are CEPT defined states. Null (State UO) No call exists. Call Initiate (Ui) This state
32、exists for an outgoing call, when the user requests call establishment from the network. Overlap Sending (U2) This state exists for an outgoing call when the user has received acknowledgement of the call establishment request which permits the user to send additional information in the overlap mode.
33、 Outgoing Call Proceeding (U3) This state exists for an outgoing call when the user has received acknowledgement that the network has received all call information necessary to effect call establishment. Call Delivered (U4) This state exists for an outgoing call, when the calling user has received i
34、ndication that remote user alerting has been initiated. Call Present (U6) This state exists for an incoming call when the user has received a call establishment request but has not (yet) responded. Call Received (U71 This state exists for an incoming call when the user has indicated alerting but has
35、 not (yet) answered. Connect Request (U8 j This state exists for an incoming call when the user has answered the call and is waiting to be awarded the call. Incoming Call Proceeding (U9) This state exists for an incoming call when the user has sent acknowledgement that the user has received all call
36、 information necessary to effect call establishment. 2.1.1.10. Active (U10) This state exists for an incoming call when the user has received an acknowledgement from the network that the user has been awarded the call. This state exists for an outgoing call when the user has received an indication t
37、hat a remote user has answered the call. 2.1.1.1 1. Disconnect Request (U 1 1 ) This state exists when the user has requested the network to clear the end-to-end connection (if any) and is waiting for a response. This state exists when the user has received an invitation to disconnect because the ne
38、twork has disconnected the end-to-end connection (if any) within the network. This state exists when the user has requested a call to be detached, prior to acknowledgement by the network. 2.1.1.12. Disconnect Indication (U12) O 2.1.1.13. Detach Request (U13) 2.1.1.14. Detach (U14) 2.1.1.15. Suspend
39、Request (U1 5) 2.1.1.16. Resume Request (U17) This state exists when the B-channel has been released but the call has not been cleared. This state exists when the user has requested the network to suspend the call and is waiting for a response. This state exists when the user has requested the netwo
40、rk to resume a previously suspended call and is waiting for a response. This state exists when the user has requested the network to release and is waiting for a response. 2.1.1.17. Release Request (U 19) Editinn nf qepternber 15, 1988 CEPT T/S*46-30*E 232b4L4 0008667 7 TIS 46-30 E Page 6 2.1 .I .18
41、. 2.1.2. 2.1.2.1. 2.1.2.2. 2.1.2.3. 2.1.2.4. 2.1.2.5. 2. I .2.6. 2.1.2.7. 2.1.2.8. 2.1.2.9. 2.1.2.10. 2.1.2.11. 2.1.2.12. 2.1.2.13. 2.1.2.14. Overlap Receiving (U25) This state exists for an incoming call when the user has acknowledged the call establishment request from the network and is prepared
42、to receive additional information (if any) in the overlap mode. Network call states The call states that may exist on the network side of the user-network interface are defined in this section. Note. All states are CCITT defined states, except Ni3 and N14 which are CEPT defined states. Null (State N
43、O) No call exists. Call Initiate (Nl) This state exists for an outgoing call, when the network has received a call establishment request but has not (yet) responded. Overlap Sending (N2) This state exists for an outgoing call when the network has acknowledged the call establishment request from the
44、user and is prepared to receive additional information (if any) in the overlap mode. Outgoing Call Proceeding (N3) This state exists for an outgoing call when the network has sent acknowledgement that the network has received all call information necessary to effect call establishment. Call Delivere
45、d (N4). This state exists for an outgoing call when the network has indicated that remote user alerting has been initiated. Call Present (N6) This state exists for an incoming call when the network has sent a call establishment request but has not (yet) received a satisfactory response. Call Receive
46、d (N7) This state exists for an incoming call when the network has received indication of alerting but has not (yet) received an answer. Connect Request (N8) This state exists for an incoming call when the network has received an answer, but the network has not (yet) awarded the call. Incoming Call
47、Proceeding (N9) This state exists for an incoming call when the network has received acknowledgement that the user has received all call information necessary to effect call establishment. This state exists for an incoming call when the network has awarded the call to the called user. This state exi
48、sts for an outgoing call when the network has indicated that the remote user has answered the call. This state exists when the network has received a request from the user to clear the end-to-end connection (if any). This state exists when the network has disconnected the end-to-end connection (if a
49、ny) within the network and has sent an invitation to disconnect the user-network connection. Active (N10) Disconnect Request (N1 1) Disconnect Indication (NI 2) Detach Request (N13) Detach (N14) This state exists when the network has requested a call be detached, prior to acknowledgement by the user. This state exists when the B-channel has been released but the call has not been cleared by either the network or the user. Edition of September 15, 1988 5 1 CEPT T/S*Yb-30*E 2326414 0008bb8 9 T/S 46-30 E Page 7 2.1.2.15. Suspend Request (N15) 2.1.2.16. Resume Request (N17) This s
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