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InfoMagic Standards 1994 January
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.rs
.\" Troff code generated by TPS Convert from ITU Original Files
.\" Not Copyright ( c) 1991
.\"
.\" Assumes tbl, eqn, MS macros, and lots of luck.
.TA 1c 2c 3c 4c 5c 6c 7c 8c
.ds CH
.ds CF
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.EN
.nr LL 40.5P
.nr ll 40.5P
.nr HM 3P
.nr FM 6P
.nr PO 4P
.nr PD 9p
.po 4P
.rs
\v | 5i'
.sp 2P
.LP
\fBRecommendation\ Z.335\fR
.RT
.sp 2P
.sp 1P
.ce 1000
\fBROUTING\ ADMINISTRATION\fR
.EF '% Fascicle\ X.7\ \(em\ Rec.\ Z.335''
.OF '''Fascicle\ X.7\ \(em\ Rec.\ Z.335 %'
.ce 0
.sp 1P
.LP
\fB1\fR \fBGeneral\fR
.sp 1P
.RT
.PP
This Recommendation has been developed in accordance to the
methodology defined in Recommendations\ Z.332 and\ Z.333.
.PP
The main part of this Recommendation deals with the model of routing administration
and glossary of the terms used is also included.
.PP
The list of operator jobs and the list of system functions to be
controlled are contained in annex\ A.
.PP
For each system function to be controlled by means of MML, one or more
MML functions can be derived and each of them can be described using the
metalanguage defined in Recommendation\ Z.333, in order to detail the relevant
information structure.
.PP
Annex B contains a list of MML functions and information structure
diagrams associated to each of them to be used as guidelines.
.RT
.sp 2P
.LP
\fB2\fR \fBIntroduction\fR
.sp 1P
.RT
.PP
The routing functions are those system functions that are in charge of
routing a call attempt toward its destination on the basis of the data
associated with the call attempt (e.g.\ the dialled digits,\ etc.) and
the data associated to the network (e.g.\ identities of the circuit sub\(hygroups
serving a certain destination,\ etc.). The destination of a call attempt
may be inside the switching system as well as outside the switching system.
If the destination
is inside the switching systems, the routing will consist of identifying the
termination that corresponds to the destination. If the destination is
outside the switching system the routing functions shall search for a free
circuit,
within a given circuit sub\(hygroup on which the call attempt will be routed.
.PP
Routing consists of functions whose parameters may vary with the
network design and the switching system design to fit the network application.
The economics of a switching system in a network application is, in part,
a
function of how well the routing functions match the network design.
.PP
The main activities for creating and maintaining routing
administration data may be summarized by the following items:
.RT
.LP
\(em
analysis of the data provided by the traffic measurement
functions;
.LP
\(em
defining the routing strategies on the basis of the achieved results;
.LP
\(em
creating new or changing the existing items, related to the routing in
the switching systems, in order to satisfy the routing
strategies.
.PP
Only the last of these items is within the scope of this
Recommendation.
.PP
This Recommendation deals with the routing administration functions
involved with the routing towards destinations outside the switching system,
whichever signalling system is used.
.RT
.sp 2P
.LP
\fB3\fR \fBRouting administration model\fR
.sp 1P
.RT
.sp 1P
.LP
3.1
\fIIntroduction\fR
.sp 9p
.RT
.PP
To service a call in order to make it proceed towards the desired called
party, two steps are pointed out:
.RT
.LP
\(em
the identification of the destination of the call made by
means of the analysis of the selection digits and by means of other
information;
.LP
\(em
the selection of a free circuit within a set of suitable
circuits on which the call may be forwarded.
.PP
The routing functions provided by a system deal mainly with the
second step and the present Recommendation relates to their administration.
In this section a model for the administration of routing functions is
reported, describing the information used.
.bp
.PP
Figure\ 1/Z.335 provides a description of the connections that exist at
the man\(hymachine interface, among the routing items (such as circuits,
circuit sub\(hygroups, routes and route groups) that can be administered
by means of MML functions.
.PP
The purpose of this model is to provide an overview of the routing
items and the relevant parameters. No specific association between parameters
and routing items is intended other than for explanatory purposes. Any
parameter 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\(hygroup level,
without changing its function.
.PP
The collection of combinations of destination and additional
parameters forms the routing table, which contains all the possibilities of
routing for a given system. One entry in this table is called routing table
element.
.RT
.LP
.rs
.sp 22P
.ad r
\fBFigure 1/Z.335, p. \fR
.sp 1P
.RT
.ad b
.RT
.sp 1P
.LP
3.2
\fIParameters\fR
.sp 9p
.RT
.PP
The parameters used in the decision process of routing a call are included
in the following list. In Figure\ 1/Z.335 they are represented by
destination, additional parameters and supplementary information. The list
is open\(hyended and not all the parameters are needed for all applications.
The list may vary according to administration needs, telecomunication network
levels,\ etc.
.PP
The methods used to evaluate these parameters within the switching
system should not be constrained by the model.
.RT
.LP
1)
Destination;
.LP
2)
Class of incoming circuit sub\(hygroup;
.LP
3)
Calling party category;
.LP
4)
Parameters for network management (e.g.\ time of day,
presence of carrier failure, etc.);
.LP
5)
Signalling system (incoming and outgoing);
.LP
6)
Transmission characteristics (incoming and outgoing);
.bp
.LP
7)
Circuit type (e.g.\ two wires, four wires);
.LP
8)
Presence of echo canceller;
.LP
9)
Transmission medium characteristics (i.e.\ presence of
satellite links);
.LP
10)
Selection of specific carrier or specific network.
.PP
The destination is identified by means of the selection digits on the basis
of the incoming route (origin information) or signalled information.
.PP
The additional parameters are those parameters that allow
identification of the possible choices for routing a call towards a given
destination. The following factors may be used as additional parameters (the
list is neither mandatory nor complete):
.RT
.LP
a)
Class of incoming circuit sub\(hygroup;
.LP
b)
Calling party category;
.LP
c)
Parameters for network management.
.PP
A combination of destination and additional parameters identify a routing
table element which contains all the possibilities to set up a call in
order to forward it.
.sp 1P
.LP
3.3
\fIRoute group\fR
.sp 9p
.RT
.PP
A route group consists of one or more routes that may be used for a given
destination. A route group may be accessed by more than one combination
of destination and additional parameters.
.RT
.sp 1P
.LP
3.4
\fIRoute\fR
.sp 9p
.RT
.PP
A route consists of one or more circuit sub\(hygroups and of some
information associated with the route describing the use of the route itself.
.PP
Examples of this information may be:
.RT
.LP
\(em
seizure signal to send (terminal, transit);
.LP
\(em
number of digits to send;
.LP
\(em
digits to add.
.PP
If the route is not present in the routing administration model
the information should be associated to other routing items.
.sp 1P
.LP
3.5
\fICircuit sub\(hygroup\fR
.sp 9p
.RT
.PP
A circuit sub\(hygroup is a set of circuits between two exchanges. In options\
A and\ B, circuits within a circuit sub\(hygroup have similar
characteristics (e.g.\ type of signalling, type of transmission path,\ etc.).
.PP
The selection of a given circuit sub\(hygroup inside a route can be made
on the basis of supplementary information such as signalling system,
transmission technique, circuit type (e.g.\ two wires, four wires), presence
of echo canceller, transmission medium characteristics (e.g.\ presence
of satellite links),\ etc. Other information may also be associated to
circuit sub\(hygroups;
examples of this information are:
.RT
.LP
\(em
traffic direction;
.LP
\(em
class of incoming circuit sub\(hygroup;
.LP
\(em
search method to select a circuit inside the sub\(hygroup.
.sp 1P
.LP
3.6
\fICircuit\fR
.sp 9p
.RT
.PP
A circuit is characterized by an identity, by its hardware
termination identity and by its sequence number inside the circuit sub\(hygroup
(this latter is only used for selection purposes in outgoing circuit
sub\(hygroups). If common channel signalling is used, a label should be
assigned to the circuit.
.bp
.RT
.sp 2P
.LP
\fB4\fR \fBAdditional information\fR
.sp 1P
.RT
.sp 1P
.LP
4.1
\fIManagement of the status of routing items\fR
.sp 9p
.RT
.PP
In order to change the routing capabilities of the
telecommunication systems, facilities are required to alter the operating
status of the items involved (i.e.\ to put a circuit in service or out of
service, etc.).
.PP
This topic is left for further study.
.RT
.sp 1P
.LP
4.2
\fIReliability mechanisms\fR
.sp 9p
.RT
.PP
In order to prevent malfunctions and errors when servicing a call, the
routing administration functions used in the telecommunication system must
implement reliability mechanisms. The most critical functions, e.g.\ change
functions, should not be provided to the operator if reliability mechanisms
are not provided.
.PP
The selection and implementation of reliability mechanisms are not
covered in this Recommendation.
.PP
However, due to the fact that the machanism used may affect the
man\(hymachine interface, it is highlighted that such aspect should be
studied and taken into account when designing the real man\(hymachine interface.
.RT
.sp 2P
.LP
\fB5\fR \fBGlossary of used terms\fR
.sp 1P
.RT
.sp 1P
.LP
\fBcircuit\fR
.sp 9p
.RT
.PP
Connection between two exchanges for one call at a time, including the
junctors that terminate the circuit.
.RT
.sp 1P
.LP
\fBcircuit sub\(hygroup\fR
.sp 9p
.RT
.PP
Group of circuits between two exchanges having the same traffic
direction (incoming, outgoing, bidirectional), the same signalling
characteristics and the same transmission medium characteristics.
.RT
.sp 1P
.LP
\fBroute\fR
.sp 9p
.RT
.PP
Collection of circuit sub\(hygroups between two exchanges that are
equivalent for routing purposes. The term route is equivalent to the concept
of \*Qcircuit group\*U as used in Recommendation\ Z.337 and in E\(hySeries
Recommendations.
.RT
.sp 1P
.LP
\fBroute group\fR
.sp 9p
.RT
.PP
The set of all the possible routes on which a call may be
forwarded to the appropriate destination.
.RT
.ce 1000
ANNEX\ A
.ce 0
.ce 1000
(to Recommendation Z.335)
.sp 9p
.RT
.ce 0
.ce 1000
\fBList of system functions to be controlled by MML and list of jobs\fR
.sp 1P
.RT
.ce 0
.LP
A.1
\fIList of system functions to be controlled by MML\fR
.sp 1P
.RT
.LP
1)
Managing the routing data base
.LP
2)
Querying the routing data base
.sp 1P
.LP
A.2
\fIList of jobs\fR
.sp 9p
.RT
.LP
1)
To create/change items involved in the routing functions or change old
ones (e.g.\ circuit sub\(hygroups, routes,\ etc.)
.LP
\(em
the purpose of the job is to create and/or change the configuration of
the switching system regarding the items involved in the
routing of a call;
.LP
\(em
the system is supposed to record the new data and to
check their static correctness;
.bp
.LP
\(em
the operator is supposed to input all needed data;
.LP
\(em
the complexity of the job may be high depending on the amount of the
data to be input for the item to be created/changed;
.LP
\(em
the frequency of the job is medium;
.LP
\(em
the job is supposed to be performed at exchange and/or OMC level.
.LP
2)
To delete items related to the routing
.LP
\(em
the purpose of the job is to delete items no longer
useful;
.LP
\(em
the system is supposed to delete the specified items
deleting the related data only if no call is currently routed on the item;
.LP
\(em
the operator is supposed to introduce the identity of the item to be
deleted;
.LP
\(em
the complexity of the job is low (if the system makes sufficient checks);
.LP
\(em
the frequency of the job is low;
.LP
\(em
the job is supposed to be performed at exchange and/or OMC level.
.LP
3)
To interrogate different kinds of information related to the routing
.LP
\(em
the purpose of the job is to get information on the
current data used by the system to perform the routing;
.LP
\(em
the system is supposed to output the information
requested in suitable formats and on the selected devices;
.LP
\(em
the operator is supposed to input the identity of the item to be interrogated
and to select the information to be retrieved;
.LP
\(em
the complexity of the job is low;
.LP
\(em
the frequency of the job is high;
.LP
\(em
the job is supposed to be performed at exchange and/or OMC level.
.ce 1000
ANNEX\ B
.ce 0
.ce 1000
(to Recommendation Z.335)
.sp 9p
.RT
.ce 0
.ce 1000
\fBGuidelines for the list of MML functions and\fR
.sp 1P
.RT
.ce 0
.ce 1000
\fBassociated information structure diagrams\fR
.ce 0
.LP
B.1
\fIIntroduction\fR
.sp 1P
.RT
.PP
This annex contains guidelines for the list of MML functions and
associated information structure diagrams related to the routing administration
model defined in Recommendation\ Z.335, \(sc\ 3.
.RT
.sp 1P
.LP
B.2
\fIList of MML functions\fR
.sp 9p
.RT
.PP
This list contains possible MML functions for routing
administration.
.PP
This list is not mandatory nor complete, it may vary according to
administration needs, telecommunication network levels, regulatory needs,\ etc.
.PP
These MML functions do not represent the actual command structure of any
real implementation of the man\(hymachine interface. Each of the MML functions
identified can be implemented by providing one or more separate distinctive
commands or several MML functions could be implemented by using a single
command.
.RT
.LP
1)
\fICreation\fR
.LP
\(em
create a circuit,
.LP
\(em
create a circuit sub\(hygroup,
.LP
Options A and B are defined in Recommendation\ Z.335, \(sc\ 3.
.FE
\(em
create a route (only options A and B)
,
.LP
\(em
create a route group (only option A)
,
.LP
\(em
create a destination.
.LP
2)
\fIDeletion\fR
.LP
\(em
delete a circuit,
.LP
\(em
delete a circuit sub\(hygroup,
.bp
.LP
\(em
delete a route (only options A and B)
,
.LP
\(em
delete a route group (only option A)
,
.LP
\(em
delete a destination.
.LP
3)
\fIInterrogation\fR
.LP
\(em
interrogate a circuit,
.LP
\(em
interrogate a circuit sub\(hygroup,
.LP
\(em
interrogate a route (only options A and B)
,
.LP
\(em
interrogate a route group (only option A)
,
.LP
\(em
interrogate a destination.
.LP
4)
\fIChanging\fR
.LP
\(em
change a circuit,
.LP
\(em
change a circuit sub\(hygroup,
.LP
\(em
change a route (only options A and B)
,
.LP
\(em
change a route group (only option A)
,
.LP
\(em
change a destination.
.sp 1P
.LP
B.3
\fIInformation structure diagrams\fR
.sp 9p
.RT
.PP
Only the information entities needed for the MML functions
previously derived have been identified. They are reported in this section
by means of diagrams representing each MML function information structure.
.PP
These diagrams represent typical routing function requirements. They are
not intended to constrain in any way the enhancement of these functions
in the light of technological advances or specific administration or regulatory
requirements.
.PP
The metalanguage used is described in Recommendation\ Z.333.
.RT
.LP
.rs
.sp 20P
.ad r
\fBFigure B\(hy1/Z.335, p.2\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 25P
.ad r
\fBFigure B\(hy2/Z.335, p.3\fR
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 22P
.ad r
\fBFigure B\(hy3/Z.335, p.4\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 17P
.ad r
\fBFigure B\(hy4/Z.335, p.5\fR
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 30P
.ad r
\fBFigure B\(hy5/Z.335, p.6\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 15P
.ad r
\fBFigure B\(hy6/Z.335, p.7\fR
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 15P
.ad r
\fBFigure B\(hy7/Z.335, p.8\fR
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 17P
.ad r
\fBFigure B\(hy8/Z.335, p.9\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 24P
.ad r
\fBFigure B\(hy9/Z.335, p.10\fR
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 22P
.ad r
\fBFigure B\(hy10/Z.335, p.11\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 21P
.ad r
\fBFigure B\(hy11/Z.335, p.12\fR
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 26P
.ad r
\fBFigure B\(hy12/Z.335, p.13\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 24P
.ad r
\fBFigure B\(hy13/Z.335, p.14\fR
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 23P
.ad r
\fBFigure B\(hy14/Z.335, p.15\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 25P
.ad r
\fBFigure B\(hy15/Z.335, p.16\fR
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 22P
.ad r
\fBFigure B\(hy16/Z.335, p.17\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 20P
.ad r
\fBFigure B\(hy17/Z.335, p.18\fR
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 27P
.ad r
\fBFigure B\(hy18/Z.335, p.19\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 20P
.ad r
\fBFigure B\(hy19/Z.335, p.20\fR
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 28P
.ad r
\fBFigure B\(hy20/Z.335, p.21\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp