`
`
`
`CCITT
`
`THE INTERNATIONAL
`TELEGRAPH AND TELEPHONE
`CONSULTATIVE COMMITTEE
`
`M.770
`
`(11/1988)
`
`SERIES M: GENERAL MAINTENANCE PRINCIPLES
`Maintenance of international transmission systems and
`telephone circuits – Common channel signalling systems
`
`
`INTER-ADMINISTRATION AGREEMENTS ON
`COMMON CHANNEL SIGNALLING SYSTEM
`No. 7
`
`
`
`
`
`
`
`
`
`
`
`
`
`Reedition of CCITT Recommendation M.770 published in
`the Blue Book, Fascicle IV.1 (1988)
`
`
`CISCO SYSTEMS, INC. Ex. 1035 Page 1
`
`
`
`
`
`
`
`
`
`NOTES
`CCITT Recommendation M.770 was published in Fascicle IV.1 of the Blue Book. This file is an extract from
`1
`the Blue Book. While the presentation and layout of the text might be slightly different from the Blue Book version, the
`contents of the file are identical to the Blue Book version and copyright conditions remain unchanged (see below).
`2
`In this Recommendation, the expression “Administration” is used for conciseness to indicate both a
`telecommunication administration and a recognized operating agency.
`
`
`
`© ITU 1988, 2008
`All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written
`permission of ITU.
`
`CISCO SYSTEMS, INC. Ex. 1035 Page 2
`
`
`
`
`
`Recommendation M.770
`
`
`INTER-ADMINISTRATION AGREEMENTS ON COMMON CHANNEL
`SIGNALLING SYSTEM No. 7
`
`Introduction
`1
`The bringing into service of new telephone circuits and signalling systems requires that a number of
`
`agreements be made in advance by the Administrations involved. Such agreements may concern, for exemple:
`–
`routing of circuits (cable, satellite, etc.);
`– mode of operation (incoming, outgoing, both-way);
`–
`circuit designation;
`– order of selection of both-way circuits.
`For common channel signalling systems, a number of agreements are needed in addition to those required for
`
`channel-associated signalling systems (e.g., Signalling System R2).
`
`This Recommendation explains the principal inter-Administration agreements which must be made in advance
`of opening a Signalling System No. 7 service and is provided as guidance to those Administrations intending to operate
`such a service.
`
`Common channel Signalling System No. 7 (SS No. 7)
`2
`Many of the aspects covered by this Recommendation relate to matters contained in the specifications of
`
`Signalling System No. 7, as appearing in the Series Q Recommendations [1]. Where appropriate, cross references to
`such Recommendations are given.
`
`Recommendations Q.701 [2] and Q.721 [3] provide functional descriptions of the Message Transfer Part
`(MTP) and Telephone User Part (TUP) respectively.
`
`The Q.780 [4] Series of Recommendations provide guidance on how to test SS No. 7. (Level 1, 2 and 3).
`
`3
`
`Aspects of SS No. 7 requiring inter-Administration agreement
`
`Signalling links and signalling security arrangements
`3.1
`Signals for a given group of speech circuits between two exchanges may be “associated” (routed on a
`
`signalling link between the two exchanges), or “non-associated” (routed on two or more signalling links in tandem,
`involving one or more signal-transfer points) or a mixture of both (Recommendation Q.701, § 3.1.2 [2].
`
`Before entering into detailed discussions on the type of signalling security arrangements required, it is
`desirable that the terminal Administrations exchange information on the type and manufacturer of their international
`exchange and the options available within their existing software systems. This information will enable each
`Administration to have an overall view of available signalling security arrangements. It will avoid misunderstandings
`and thus enable rapid progress in establishing detailed arrangements. Subsequently, agreement on the following matters
`will be required:
`i) The use of “associated” and/or “non-associated” modes of signalling.
`ii) The choice of signalling transfer points (STPs) in the case where the “non-associated” mode of signalling
`is used.
`iii) Security measures against signalling network link failure, e.g., the use of load sharing between link sets. If
`load sharing between link sets is to be used, agreement must be reached as to the number of link sets
`involved.
`iv) Alternative routing within the signalling network in the event of failure of a link set, i.e., if load sharing is
`not used, which STPs are available for a given signalling network relation, and the order of selection of
`these. Due regard must be paid to the limitation of the number of STPs in tandem in a given signalling
`network relation (see Recommendation Q.705 § 5) [5].
`
`
`
`
`
`Fascicle IV.1 – Rec. M.770
`
`1
`
`CISCO SYSTEMS, INC. Ex. 1035 Page 3
`
`
`
`
`
`v) The routing of the signalling network links must ensure that the propagation delay of the links is as low as
`possible, and not significantly higher than that of the speech circuits which are served by Signalling
`System No. 7. This is to minimize the initial speech clipping of the verbal answer from the called party.
`The above factors must also be considered in any restoration plans, although the non-availability of links
`may force administrations to accept the possibility of clipping under failure conditions.
`vi) The nature of the signalling network link to be used, e.g., 4.8 kbit/s analogue or 64 kbit/s digital,
`transmission routing, etc.
`vii) The method of error correction to be employed in a given signalling relation, i.e., basic or preventive
`cyclic retransmission (see Recommendation Q.703 § 5) [6].
`viii) Emergency restart conditions. (If there is automatic allocation of signalling terminals or signalling data
`links at the end of a signalling link, it must be ensured that the value (T2) of the timeout is different at each
`end (see Recommendation Q.703, § 7.3 and Q.704, § 3.4.3) [6] and [7]).
`
`Mode of signalling
`3.2
`Signalling System No. 7 provides for two basic modes of sending signalling information namely, “en-bloc” or
`
`“overlap” (Recommendation Q.724) [8].
`
`Signalling network consideration for cross-border traffic
`3.3
`For cross-border traffic between signalling points, a bilateral agreement needs to be made for the routing label
`
`assignment of signalling point codes.
`
`Two alternative arrangements are described in Recommendation Q.705, § 6 [5]. One arrangement provides for
`signalling points which are handling cross-border traffic to be given signal point codes taken from the international
`numbering plan contained in Recommendation Q.708 [9]. The other provides for these signalling points to be identified
`by common national point codes.
`
`Routing label assignment
`3.4
`The routing label is that part of the message label which contains the information necessary to deliver the
`
`message to its destination point. It comprises the following (see Recommendation Q.704, § 2.2) [7]:
`– destination point code (DPC);
`– originating point code (DPC);
`–
`signalling link selection (SLS) field or signalling link code (SLC).
`DPC and OPC labelling will be in accordance with Recommendation Q.708 [9]. However it may be necessary
`
`to have a bilateral agreement for the SLS, so that it can be assigned individually to signalling links.
`
`Circuit identification code
`3.5
`The circuit identification code (CIC) indicates one speech circuit among those directly interconnecting the
`
`destination and the originating points. The allocation of CICs to individual circuits is determined by bilateral agreement
`and/or in accordance with predetermined rules. See Recommendation Q.723, § 2.2.3 [10].
`
`Reset of circuit and circuit group messages
`3.6
`In systems which maintain status in memory there may be occasions when the memory becomes mutilated. In
`
`such cases the circuits must be reset to the idle condition in both exchanges to make them available for new traffic. Since
`the exchange with mutilated memory does not know whether the circuits are idle, busy outgoing, busy incoming,
`blocked, etc., reset-circuit signals or a circuit group reset should be sent as appropriate for the affected circuits (see
`Recommendation Q.724, § 1.15) [8].
`
`Under certain failure conditions however, where a large number of circuits is involved, it is possible that some
`realisations of SS No. 7 terminal equipment will be unable to process the volume of reset messages generated. It is
`necessary, therefore, that Administrations agree bilaterally whether circuit and circuit group messages should both be
`used.
`
`2
`
`Fascicle IV.1 – Rec. M.770
`
`
`
`
`
`CISCO SYSTEMS, INC. Ex. 1035 Page 4
`
`
`
`
`
`Use of the circuit continuity check procedure
`3.7
`Because the SS No. 7 signalling does not pass over the speech path, facilities should be provided for making a
`
`continuity check of the speech paths (see Recommendation Q.724, § 1.4) [8].
`
`Use of this procedure on a particular circuit will depend on the type of transmission system (e.g., analogue,
`digital, mixed analogue/digital) which is used for the circuit and whether end-to-end supervision is provided on the
`transmission system. It should therefore be bilaterally agreed.
`
`Choice of the time slot to be used within the primary order digital path for the signalling link
`3.8
`In the case where time slot 16 is utilized for circuit supervision purposes (see Recommendation Q.33, § A.1)
`
`[11], it is necessary to agree bilaterally on which time slot within the primary order digital path should be used for the
`signalling link.
`
`Changing from one specification of the signalling system to another
`3.9
`If an Administration changes from one version of the specification of the signalling system to another, distant
`
`Administrations should be informed as a precautionary measure before the change takes place since potential
`interworking problems can then be anticipated. It is desirable therefore, that Administrations should be aware of the need
`for, and agree to, this exchange of information.
`
`Timing on inter-Administration agreements
`4
`Due to the differing practices and procedures of Administrations no specific timetable for the inter-
`
`Administration agreements necessary on SS No. 7 can be offered. However, experience indicates that initial discussions
`between Administrations concerning the implementation of a new common channel signalling system should preferably
`commence about two years prior to the required “ready for service” date.
`
`References
`CCITT Recommendation Specification of Signalling System No. 7, Vol. VI, Recommendations Q.701-Q.795.
`CCITT Recommendation Functional description of the signalling system (Message Transfer Part), Vol. VI,
`Recommendation Q.701.
`CCITT Recommendation Functional description of the signalling system (Telephone User part (TUP)),
`Vol. VI, Recommendation Q.721.
`CCITT Recommendation Signalling System No. 7 test specification, general description, Vol. VI,
`Recommendation Q.780.
`CCITT Recommendation Signalling network structure, Vol. VI, Recommendation Q.705.
`CCITT Recommendation Signalling link, Vol. VI, Recommendation Q.703.
`CCITT Recommendation Signalling network functions and messages, Vol. VI, Recommendation Q.704.
`CCITT Recommendation Signalling procedures, Vol. VI, Recommendation Q.724.
`CCITT Recommendation Numbering of international signalling point codes, Vol. VI, Recommendation
`Q.708.
`CCITT Recommendation Formats and codes, Vol. VI, Recommendation Q.723.
`CCITT Recommendation Protection against the effects of faulty transmission on groups of circuits Vol. VI,
`Recommendation Q.33.
`
`
`
`Fascicle IV.1 – Rec. M.770
`
`3
`
`
`[1]
`[2]
`
`[3]
`
`[4]
`
`[5]
`[6]
`[7]
`[8]
`[9]
`
`[10]
`[11]
`
`
`
`
`
`CISCO SYSTEMS, INC. Ex. 1035 Page 5
`
`
`
`CISCO SYSTEMS, INC. Ex. 1035 Page 6
`
`CISCO SYSTEMS, INC. Ex. 1035 Page 6
`
`
`
`
`
`CISCO SYSTEMS, INC. Ex. 1035 Page 7
`
`
`
`
`
`CISCO SYSTEMS, INC. Ex. 1035 Page 7
`
`
`
`
`
`
`
`Series A
`
`Series B
`
`Series C
`
`ITU-T RECOMMENDATIONS SERIES
`Organization of the work of the ITU-T
`
`Means of expression: definitions, symbols, classification
`
`General telecommunication statistics
`
`Series D
`
`General tariff principles
`
`Series E
`
`Series F
`
`Overall network operation, telephone service, service operation and human factors
`
`Non-telephone telecommunication services
`
`Series G
`
`Transmission systems and media, digital systems and networks
`
`Series H
`
`Audiovisual and multimedia systems
`
`Series I
`
`Series J
`
`Integrated services digital network
`
`Transmission of television, sound programme and other multimedia signals
`
`Series K
`
`Protection against interference
`
`Series L
`
`Construction, installation and protection of cables and other elements of outside plant
`
`Series M
`
`international transmission systems, telephone circuits,
`TMN and network maintenance:
`telegraphy, facsimile and leased circuits
`
`Series N
`
`Series O
`
`Series P
`
`Maintenance: international sound programme and television transmission circuits
`
`Specifications of measuring equipment
`
`Telephone transmission quality, telephone installations, local line networks
`
`Series Q
`
`Switching and signalling
`
`Series R
`
`Telegraph transmission
`
`Telegraph services terminal equipment
`
`Terminals for telematic services
`
`Telegraph switching
`
`Data communication over the telephone network
`
`Data networks and open system communications
`
`Global information infrastructure and Internet protocol aspects
`
`Languages and general software aspects for telecommunication systems
`
`
`
`Series S
`
`Series T
`
`Series U
`
`Series V
`
`Series X
`
`Series Y
`
`Series Z
`
`
`
`
`
`Printed in Switzerland
`Geneva, 2008
`
`CISCO SYSTEMS, INC. Ex. 1035 Page 8