1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 : TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU-!.G13-!#().%G0G0,!.5!%2/54).G0G0!$-).)342!4)/.)45G134G0G0RecommendationG0G0: (Extract from the “LUEG0“OOK)NOTES1 ITU-T Recommendation Z.335 was published in Fascicle X.7 of the Blue Book. This file is an ext
2、ract from theBlue Book. While the presentation and layout of the text might be slightly different from the Blue Book version, thecontents of the file are identical to the Blue Book version and copyright conditions remain unchanged (see below).2 In this Recommendation, the expression “Administration”
3、 is used for conciseness to indicate both atelecommunication administration and a recognized operating agency. ITU 1988, 1993All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic ormechanical, including photocopying and microfilm, with
4、out permission in writing from the ITU.Fascicle X.7 - Rec. Z.335 1Recommendation Z.335Fascicle X.7 - Rec. Z.335ROUTING ADMINISTRATION1 GeneralThis Recommendation has been developed in accordance to the methodology defined inRecommendations Z.332 and Z.333.The main part of this Recommendation deals w
5、ith the model of routing administration and glossary of the termsused is also included.The list of operator jobs and the list of system functions to be controlled are contained in annex A.For each system function to be controlled by means of MML, one or more MML functions can be derived andeach of t
6、hem can be described using the metalanguage defined in Recommendation Z.333, in order to detail therevelant information structure.Annex B contains a list of MML functions and information structure diagrams associated to each of them to beused as guidelines.2 IntroductionThe routing functions are tho
7、se system functions that are in charge of routing a call attempt toward itsdestination on the basis of the data associated with the call attempt (e.g. the dialled digits, etc.) and the data associatedto the network (e.g. identities of the circuit sub-groups serving a certain destination, etc.). The
8、destination of a callattempt may be inside the switching system as well as outside the switching system. If the destination is inside theswitching systems, the routing will consist of identifying the termination that corresponds to the destination. If thedestination is outside the switching system t
9、he routing functions shall search for a free circuit, within a given circuitsub-group on which the call attempt will be routed.Routing consists of functions whose parameters may vary with the network design and the switching systemdesign to fit the network application. The economics of a switching s
10、ystem in a network application is, in part, afunction of how well the routing functions match the network design.The main activities for creating and maintaining routing administration data may be summarized by thefollowing items: analysis of the data provided by the traffic measurement functions; d
11、efining the routing strategies on the basis of the achieved results; creating new or changing the existing items, related to the routing in the switching systems, in order tosatisfy the routing strategies.Only the last of these items is within the scope of this Recommendation.This Recommendation dea
12、ls with the routing administration functions involved with the routing towardsdestinations outside the switching system, whichever signalling system is used.3 Routing administration model3.1 IntroductionTo service a call in order to make it proceed towards the desired called party, two steps are poi
13、nted out: the identification of the destination of the call made by means of the analysis of the selection digits and bymeans of other information; the selection of a free circuit within a set of suitable circuits on which the call may be forwarded.The routing functions provided by a system deal mai
14、nly with the second step and the present Recommendationrelates to their administration. In this section a model for the administration of routing functions is reported, describingthe information used.Figure 1/Z.335 provides a description of the connections that exist at the man-machine interface, am
15、ong therouting items (such as circuits, circuit sub-groups, routes and route groups) that can be administered by means of MMLfunctions.2 Fascicle X.7 - Rec. Z.335The purpose of this model is to provide an overview of the routing items and the relevant parameters. Nospecific association between param
16、eters and routing items is intended other than for explanatory purposes. Anyparameter can be associated to any routing item depending on the specific needs of an administration or of the network:for example, the type of signalling system may be determined at route group, route or circuit sub-group l
17、evel, withoutchanging its function.The collection of combinations of destination and additional parameters forms the routing table, which containsall the possibilities of routing for a given system. One entry in this table is called routing table element.3.2 ParametersThe parameters used in the deci
18、sion process of routing a call are included in the following list. In Figure1/Z.335 they are represented by destination, additional parameters and supplementary information. The list is open-ended and not all the parameters are needed for all applications. The list may vary according to administrati
19、on needs,telecomunication network levels, etc.The methods used to evaluate these parameters within the switching system should not be constrained by themodel.1) Destination;2) Class of incoming circuit sub-group;3) Calling party category;4) Parameters for network management (e.g. time of day, presen
20、ce of carrier failure, etc.);5) Signalling system (incoming and outgoing);6) Transmission characteristics (incoming and outgoing);7) Circuit type (e.g. two wires, four wires);8) Presence of echo canceller;9) Transmission medium characteristics (i.e. presence of satellite links);10) Selection of spec
21、ific carrier or specific network.Fascicle X.7 - Rec. Z.335 3The destination is identified by means of the selection digits on the basis of the incoming route (origininformation) or signalled information.The additional parameters are those parameters that allow identification of the possible choices
22、for routing acall towards a given destination. The following factors may be used as additional parameters (the list is neithermandatory nor complete):a) Class of incoming circuit sub-group;b) Calling party category;c) Parameters for network management.A combination of destination and additional para
23、meters identify a routing table element which contains all thepossibilities to set up a call in order to forward it.3.3 Route groupA route group consists of one or more routes that may be used for a given destination. A route group may beaccessed by more than one combination of destination and addit
24、ional parameters.3.4 RouteA route consists of one or more circuit sub-groups and of some information associated with the route describingthe use of the route itself.Examples of this information may be: seizure signal to send (terminal, transit); number of digits to send; digits to add.If the route i
25、s not present in the routing administration model the information should be associated to otherrouting items.3.5 Circuit sub-groupA circuit sub-group is a set of circuits between two exchanges. In options A and B, circuits within a circuit sub-group have similar characteristics (e.g. type of signall
26、ing, type of transmission path, etc.).The selection of a given circuit sub-group inside a route can be made on the basis of supplementaryinformation such as signalling system, transmission technique, circuit type (e.g. two wires, four wires), presence ofecho canceller, transmission medium characteri
27、stics (e.g. presence of satellite links), etc. Other information may also beassociated to circuit sub-groups; examples of this information are: traffic direction; class of incoming circuit sub-group; search method to select a circuit inside the sub-group.3.6 CircuitA circuit is characterized by an i
28、dentity, by its hardware termination identity and by its sequence number insidethe circuit sub-group (this latter is only used for selection purposes in outgoing circuit sub-groups). If common channelsignalling is used, a label should be assigned to the circuit.4 Additional information4.1 Management
29、 of the status of routing itemsIn order to change the routing capabilities of the telecommunication systems, facilities are required to alter theoperating status of the items involved (i.e. to put a circuit in service or out of service, etc.).This topic is left for further study.4.2 Reliability mech
30、anismsIn order to prevent malfunctions and errors when servicing a call, the routing administration functions used inthe telecommunication system must implement reliability mechanisms. The most critical functions, e.g. changefunctions, should not be provided to the operator if reliability mechanisms
31、 are not provided.4 Fascicle X.7 - Rec. Z.335The selection and implementation of reliability mechanisms are not covered in this Recommendation.However, due to the fact that the mechanism used may affect the man-machine interface, it is highlighted thatsuch aspect should be studied and taken into acc
32、ount when designing the real man-machine interface.5 Glossary of used termscircuitConnection between two exchanges for one call at a time, including the junctors that terminate the circuit.circuit sub-groupGroup of circuits between two exchanges having the same traffic direction (incoming, outgoing,
33、 bidirectional),the same signalling characteristics and the same transmission medium characteristics.routeCollection of circuit sub-groups between two exchanges that are equivalent for routing purposes. The termroute is equivalent to the concept of “circuit group“ as used in Recommendation Z.337 and
34、 in E-SeriesRecommendations.route groupThe set of all the possible routes on which a call may be forwarded to the appropriate destination.ANNEX A(to Recommendation Z.335)List of system functions to be controlled by MML and list of jobsA.1 List of system functions to be controlled by MML1) Managing t
35、he routing data base2) Querying the routing data baseA.2 List of jobs1) To create/change items involved in the routing functions or change old ones (e.g. circuit sub-groups,routes, etc.) the purpose of the job is to create and/or change the configuration of the switching system regarding theitems in
36、volved in the routing of a call; the system is supposed to record the new data and to check their static correctness; the operator is supposed to input all needed data; the complexity of the job may be high depending on the amount of the data to be input for the item tobe created/changed; the freque
37、ncy of the job is medium; the job is supposed to be performed at exchange and/or OMC level.2) To delete items related to the routing the purpose of the job is to delete items no longer useful; the system is supposed to delete the specified items deleting the related data only if no call is currently
38、routed on the item; the operator is supposed to introduce the identity of the item to be deleted; the complexity of the job is low (if the system makes sufficient checks);Fascicle X.7 - Rec. Z.335 5 the frequency of the job is low; the job is supposed to be performed at exchange and/or OMC level.3)
39、To interrogate different kinds of information related to the routing the purpose of the job is to get information on the current data used by the system to perform therouting; the system is supposed to output the information requested in suitable formats and on the selecteddevices; the operator is s
40、upposed to input the identity of the item to be interrogated and to select the informationto be retrieved; the complexity of the job is low; the frequency of the job is high; the job is supposed to be performed at exchange and/or OMC level.ANNEX B(to Recommendation Z.335)Guidelines for the list of M
41、ML functions andassociated information structure diagramsB.1 IntroductionThis annex contains guidelines for the list of MML functions and associated information structure diagramsrelated to the routing administration model defined in Recommendation Z.335, 3.B.2 List of MML functionsThis list contain
42、s possible MML functions for routing administration.This list is not mandatory nor complete, it may vary according to administration needs, telecommunicationnetwork levels, regulatory needs, etc.These MML functions do not represent the actual command structure of any real implementation of the man-m
43、achine interface. Each of the MML functions identified can be implemented by providing one or more separatedistinctive commands or several MML functions could be implemented by using a single command.1) Creation create a circuit, create a circuit sub-group, create a route (only options A and B)1), c
44、reate a route group (only option A)1), create a destination.2) Deletion delete a circuit, delete a circuit sub-group,_1)Options A and B are defined in Recommendation Z.335, 3.6 Fascicle X.7 - Rec. Z.335 delete a route (only options A and B)2), delete a route group (only option A)2), delete a destina
45、tion.3) Interrogation interrogate a circuit, interrogate a circuit sub-group, interrogate a route (only options A and B)2), interrogate a route group (only option A)2), interrogate a destination.4) Changing change a circuit, change a circuit sub-group, change a route (only options A and B)2), change
46、 a route group (only option A)2), change a destination.B.3 Information structure diagramsOnly the information entities needed for the MML functions previously derived have been identified. They arereported in this section by means of diagrams representing each MML function information structure.Thes
47、e diagrams represent typical routing function requirements. They are not intended to constrain in any waythe enhancement of these functions in the light of technological advances or specific administration or regulatoryrequirements.The metalanguage used is described in Recommendation Z.333._2)Options A and B are defined in Recommendation Z.335, 3.Fascicle X.7 - Rec. Z.335 7 8 Fascicle X.7 - Rec. Z.335 Fascicle X.7 - Rec. Z.335 9 10 Fascicle X.7 - Rec. Z.335 Fascicle X.7 - Rec. Z.335 11 12 Fascicle X.7 - Rec. Z.335 Fascicle X.7 - Rec. Z.335 13 14 Fascic
