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- Figure B-28/Q.764 (Feuillet 1 sur 2), (N), p. 1
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- Figure B-28/Q.764 (Feuillet 2 sur 2), (N), p. 2
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- Figure B-29/Q.764, (N), p. 3
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- Figure B-30/Q.764, (N), p. 4
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- Figure B-31/Q.764 (Feuillet 1 sur 6), (N), p. 5
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- Figure B-31/Q.764 (Feuillet 2 sur 6), (N), p. 6
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- Figure B-31/Q.764 (Feuillet 3 sur 6), (N), p. 7
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- Figure B-31/Q.764 (Feuillet 4 sur 6), (N), p. 8
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- Figure B-31/Q.764 (Feuillet 5 sur 6), (N), p. 9
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- Figure B-31/Q.764 (Feuillet 6 sur 6), (N), A L'ITALIENNE, p. 10
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- Figure B-32/Q.764 (Feuillet 1 sur 2), (N), p. 11
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- Figure B-32/Q.764 (Feuillet 2 sur 2), (N), p. 12
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- Figure B-33/Q.764 (Feuillet 1 sur 3), (N), p. 13
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- Figure B-33/Q.764 (Feuillet 2 sur 3), (N), p. 14
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- Figure B-33/Q.764 (Feuillet 3 sur 3), (N), p. 15
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- Figure B-34/Q.764, (N), p. 16
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- Figure B-35/Q.764 (Feuillet 1 sur 3), (N), p. 17
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- Figure B-35/Q.764 (Feuillet 2 sur 3), (N), p. 18
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- Figure B-35/Q.764 (Feuillet 3 sur 3), (N), p. 19
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- Figure B-36/Q.764 (Feuillet 1 sur 2), (N), p. 20
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- Figure B-36/Q.764 (Feuillet 2 sur 2), (N), p. 21
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- Figure B-37/Q.764 (Feuillet 1 sur 6), (N), p. 22
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- Figure B-37/Q.764 (Feuillet 2 sur 6), (N), p. 23
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- Figure B-37/Q.764 (Feuillet 3 sur 6), (N), p. 24
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- Figure B-37/Q.764 (Feuillet 4 sur 6), (N), p. 25
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- Figure B-37/Q.764 (Feuillet 5 sur 6), (N), p. 26
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- Figure B-37/Q.764 (Feuillet 6 sur 6), (N), p. 27
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- Figure B-38/Q.764 (Feuillet 1 sur 2), (N), p. 28
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- Figure B-38/Q.764 (Feuillet 2 sur 2), (N), p. 29
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- Figure B-39/Q.764, (N), p. 30
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- Figure B-40/Q.764, (N), p. 31
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- APPENDIX I
- (to Recommendation Q.764)
-
- Contents of the interface elements between
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- the ISDN user part and the SCCP
-
- These interface elements are defined in SCCP Recommendations
- (Q.711-Q.716) and are included here for information.
-
-
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- I.1 Contents of the REQUEST type 1
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- The REQUEST type 1 interface element may contain the following
- parameters:
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- - connection identification (for further study);
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- - receipt confirmation selection;
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- - expedited data selection;
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- - quality of service parameter set.
-
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- I.2 Contents of the REQUEST type 2
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- The REQUEST type 2 interface element may contain the following
- parameters:
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- - network indicator (for further study);
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- - protocol class;
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- - credit;
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- - connection identification (for further study);
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- - source local reference;
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- - originating signalling point code;
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- - reply request;
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-
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- - refusal indicator.
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- I.3 Contents of the REPLY
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- The REPLY interface element may contain the following parame-
- ters:
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- - source local reference;
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- - protocol class;
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- - credit;
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- - connection identification (for further study).
-
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- Recommendation Q.766
-
- PERFORMANCE OBJECTIVES IN THE INTEGRATED
-
-
-
- SERVICES DIGITAL NETWORK APPLICATION
-
-
- 1 Introduction
-
-
- This Recommendation gives the requirements of the Integrated
- Services Digital Network (ISDN) application call control service
- supported by Signalling System No. 7.
-
- In Recommendation Q.706, the Message Transfer Part performance
- is described. The Message Transfer Part supports the ISDN applica-
- tion of Signalling System No. 7 and provision of a signalling net-
- work to support the ISDN application must take account of the per-
- formance of the Message Transfer Part and the requirements of the
- ISDN application. For example, taking account of the message
- transfer times in Recommendation Q.706 and the requirements for
- message transfer times between two ISDN exchanges, a figure may be
- derived for the total permissible number of signalling links in
- tandem for a particular call.
-
-
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- 2 Signalling availability
-
-
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- 2.1 Signalling route set availability
-
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- The availability of a signalling route set is determined by
- the availability of the individual components of the signalling
- network (signalling links and the signalling points) and by the
-
-
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-
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- structure of a signalling network.
-
- The availability of a signalling route set should not be less
- than 0.99998, corresponding to a downtime of 10 minutes per year
- for a user signalling relation.
-
-
- 2.2 Signalling network availability
-
-
- The availability of the signalling network should be suffi-
- ciently high as to meet the signalling route set downtime objec-
- tives stated in S 2.1. The signalling network architecture selected
- will strongly influence the availability. In general, the greater
- the number of link sets in tandem in a signalling route set the
- more redundant signalling paths that will be needed to meet the
- availability objective for the signalling route set or user signal-
- ling relation.
-
-
- 3 Signalling dependability
-
-
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- 3.1 General
-
-
- The ISDN application is different from other applications,
- such as telephony and data, in that there may be multiple paths
- involved for any given ISDN call. There may be several circuits
- (e.g. telephone conferencing) for either telephony or data and
- non-circuit related connections for access to data bases or for
- terminal-to-terminal control. This diverse set of uses may require
- closer control of the signalling network resources than might be
- required for other more simple applications.
-
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- 3.1.1 Probability of false operation
-
-
- By means of error detection (see Recommendation Q.703) as well
- as transmission fault indication (see Recommendations G.732 [1] and
- G.733 [2], it is ensured that, overall, not more than one in 108 of
- all signal units transmitted is accepted that, due to errors, will
- cause false operation.
-
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- 3.2 Probability of signalling malfunction
-
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- Unsuccessful calls may be caused by undetected errors, loss of
- messages, or messages delivered out of sequence (during emergency
- situations within the signalling network) and may result in:
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- - incomplete call set-up,
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- - misrouted calls (e.g. connection of wrong
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- numbers),
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- - calls routed correctly but mishandled (e.g. false
- clearing),
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- - inability to access a data base.
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- Considering the above conditions and the performance for the
- Message Transfer Part, no more than 2 in 105 (provisional value) of
- all ISDN calls should be unsuccessful due to signalling malfunc-
- tion.
-
- Note - No more than 1 in 105 of all ISDN circuit connections
- should be unsuccessful due to signalling malfunction.
-
-
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-
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- 4 Signalling delay
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-
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- 4.1 Functional reference points and transfer time com-
- ponents
-
-
-
- Figure ccitt-35600, (M), p.
-
-
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- 4.2 Delays
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-
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- 4.2.1 cross-office transfer time, Tvcvu
-
-
- Tc\duis the period which starts when the last bit of the sig-
- nal unit leaves the incoming signalling data link and ends when the
- last bit of the signal unit enters the outgoing signalling data
- link for the first time. It therefore includes the queuing delay in
- the absence of disturbances but not the additional queuing delay
- caused by retransmission.
-
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- 4.2.2 user handling time, Tvhvu
-
-
- Th\duis the period which starts when the last bit of the mes-
- sage has entered the upper layer functions and ends when the last
- bit of the derived message has left the upper layer functions.
-
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- 4.2.3 Objectives for cross-office transfer time, Tc\du
-
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-
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- The figures in Table 1/Q.766 are the objectives for the
- cross-office transfer time Tc\dufor the ISDN signalling points in
- the signalling network. These figures are related to a signalling
- bit rate of 64 kbit/s.
- H.T. [T1.766]
- TABLE 1/Q.766 | u1)
- lw(60p) | lw(60p) | lw(30p) | lw(30p) .
- Tableau 1/Q.766 [T1.766], p.
-
-
-
-
- A processing intensive message is one that arrives at an
- exchange and requires detailed examination (and possibly modifica-
- tion) before it is transmitted to the next exchange.
-
- A simple message is one that requires little or no examination
- or modification (typically only label translation) before it is
- transmitted to the next exchange.
-
-
- 4.3 Effect of retransmission
-
-
- As a consequence of correction by retransmission, not more
- than one in 104 signals should be delayed more than 300 ms as a
- long-term average. This requirement refers to each signalling link.
-
- This requirement is laid down in order to ensure satisfactory
- answer delays.
-
- 5 Signalling system limitations
-
-
-
- 5.1 Labelling potential
-
-
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- 5.1.1 Signalling points
-
-
- The label of the Signalling System No. 7 for the ISDN applica-
- tion provides the potential to identify 16 | 84 signalling points.
-
-
- 5.1.2 Number of circuits in a user signalling relation
-
-
- There may be up to 4096 circuits (4096 channels in each direc-
- tion) for each user signalling relation.
-
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- 5.1.3 Number of SCCP connections in a user signalling rela-
- tion
-
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-
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- There may be up to 224 SCCP connections available at an ISDN
- signalling point. All of these may be available for any given user
- signalling relation, but must be shared over all signalling rela-
- tions.
-
-
- 5.2 Number of ISDN call identities at a signalling point
-
-
- There may be up to 224 (value for further study) simultaneous
- ISDN calls at a signalling point with the 224 call identities
- available. The use of ISDN call identities is for further study.
-
-
- References
-
-
- [1] CCITT Recommendation Characteristics of primary PCM
- multiplex equipment operating at 2048 kbit/s , Rec. G.732.
-
- [2] CCITT Recommendation Characteristics of primary PCM
- multiplex equipment operating at 1544 kbit/s , Rec. G.733.
-
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- Blanc
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- MONTAGE : PAGE 438 = PAGE BLANCHE
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