.rs
.\" Troff code generated by TPS Convert from ITU Original Files
.\"                 Not Copyright ( c) 1991 
.\"
.\" Assumes tbl, eqn, MS macros, and lots of luck.
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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'
.LP
(cs,2)  \ 
Disk. 360  \ 
NF01/027
\ 
(OPM = NF01)
.LP
\fR (cs,3)  \ 
Disk. 361  \ 
NF01/034
\ 
(OPM = NF02)
.LP
\fR \fB(ATTENTION NOTE REPETITIVE COMMENCANT AU NUMERO 15):\fR 
.LP
	
.LP
xx xx xxxx
.FS
National option.
.FE
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.FS
National option.
.FE
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National option.
.FE
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National option.
.FE
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National option.
.FE
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National option.
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National option.
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National option.
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National option.
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National option.
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National option.
.FE
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National option.
.FE
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National option.
.FE
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National option.
.FE
.LP
.bp
.LP
(1BT) (BT10)
Disk. 360  NF01/005
.LP
.sp 2
\fB(67.TE.05.E)\fR 
.LP
.sp 2
(A1.23e)  / [26e]  \ \ \ \ 
\fBFOLIOS:\ \ 
175 \(em 227 \fR \fB(DO PRC.COSY.2)\fR 
.LP
.sp 2
.LP
.EF '%	Fascicle\ VI.7\ \(em\ Rec.\ Q.704''
.OF '''Fascicle\ VI.7\ \(em\ Rec.\ Q.704	%'
.LP
MEP  \fB[PA1]\fR : OK=
[1]
.LP
.sp 2
Saisie
25.04.89   SB
.LP
ID +  LASER
22.05.89   CW
.LP
MAJ diskette
24.05.89   CW
.LP
Corr. LASER (1re \*'epreuve) = 3eme
26.05.89   GG
.LP
Espaces r\*'eserv\*'es
30.05.89   CW
.LP
.sp 1
\fBAJOUTER (PA1) (CL1,0,0,0) pour MEP\fR 
.LP
MEP + LASER
13.06.89   GH/PC
.LP
Corr. MEP
........   ..
.LP
Insertion des tableaux (tabulateurs...)
........   ..
.LP
BAT du 6/6/89\ 
07.07.89 \ 
PV
.LP
MAJ s/disquettes
2.07.89   CD
.LP
.bp
.LP
\fBMONTAGE: FIN DU \(sc 12.7 EN\(hyTETE DE CETTE PAGE\fR 
.sp 2P
.LP
\v'29P'
\fB13\fR 	\fBSignalling route management\fR 
.sp 1P
.RT
.sp 1P
.LP
13.1
	\fIGeneral\fR 
.EF '%	Fascicle\ VI.7\ \(em\ Rec.\ Q.704''
.OF '''Fascicle\ VI.7\ \(em\ Rec.\ Q.704	%'
.sp 9p
.RT
.PP
National option.
.FE
The purpose of the signalling route management function is to
ensure a reliable exchange of information between the signalling points 
about the availability of the signalling routes. 
.PP
The unavailability, restriction
and availability of
a signalling route is communicated by means of the transfer\(hyprohibited,
transfer\(hyrestricted
and transfer allowed procedures,
respectively in \(sc\(sc\ 13.2, 13.4 and\ 13.3.
.PP
Recovery of signalling route status information is made by means of
the signalling\(hyroute\(hyset\(hytest procedure specified in \(sc\ 13.5.
.PP
In the international signalling network, congestion of a route set is communicated 
by means of the transfer\(hycontrolled\ (TFC) messages specified in 
\(sc\ 13.6.
.PP
In national networks, congestion of a signalling route set may be
communicated by means of the\ TFC as specified in \(sc\(sc\ 13.7 and\ 13.8 
and the 
signalling route set congestion test procedure specified in
\(sc\ 13.9.
.RT
.sp 2P
.LP
13.2
	\fITransfer prohibited\fR 
.sp 1P
.RT
.PP
13.2.1
The transfer\(hyprohibited procedure is performed at a signalling
point acting as a signalling transfer point for messages relating to a given
destination, when it has to notify one or more adjacent signalling points 
that they must no longer route the concerned messages via that signalling 
transfer point. 
.bp
.sp 9p
.RT
.PP
The transfer\(hyprohibited procedure makes use of the
transfer\(hyprohibited message which contains:
.LP
	\(em
	the label, indicating the destination and originating
points;
.LP
	\(em
	the transfer\(hyprohibited signal; and
.LP
	\(em
	the destination for which traffic transfer is no longer
possible.
.PP
Format and code of these messages appear in \(sc\ 15.
.PP
Transfer prohibited messages are always addressed to an adjacent
signalling point. They may use any available signalling route that leads to
that signalling point.
.FS
The possibility of referring to a more general
destination than a
single signalling point (e.g.\ a signalling region), or more restrictive
destination than a signalling point is for further study.
.FE
.RT
.PP
13.2.2
A transfer\(hyprohibited message relating to a given destination\ X
is sent from a signalling transfer point\ Y in the following cases:
.sp 9p
.RT
.LP
	i)
	When signalling transfer point Y starts to route (at
changeover, changeback, forced or controlled rerouting) signalling destined 
to signalling point\ X via a signalling transfer point\ Z not currently 
used by 
signalling transfer point\ Y for this traffic. In this case the
transfer\(hyprohibited message is sent to signalling transfer point\ Z.
.LP
	ii)
	When signalling transfer point Y recognizes that it is
unable to transfer signalling traffic destined to signalling point\ X (see
\(sc\(sc\ 5.3.3 and\ 7.2.3). In this case a transfer\(hyprohibited message 
is sent to all accessible adjacent signalling points (Broadcast method). 
.LP
	iii)
	 When a message destined to signalling point X is received at signalling 
transfer point\ Y and\ Y is unable to transfer the message. In this case 
the transfer prohibited message is sent to the adjacent signalling point 
from which the message concerned was received (Response Method). 
.LP
	iv)
	When an adjacent signalling point Z becomes accessible,
STP\ Y sends to\ Z a transfer prohibited message concerning destination\ 
X, if\ X is inaccessible from\ Y (see \(sc\ 9). 
.LP
	v)
	 When a signalling transfer point Y restarts, it broadcasts to all accessible 
adjacent signalling points transfer prohibited messages 
concerning destination\ X, if\ X is inaccessible from\ Y (see \(sc\ 9).
.PP
As long as transfer\(hyprohibited messages for a destination are
being transmitted according to criteria\ i), ii), iv), or\ v) above, and also
within\ T8 (see \(sc\ 16) after the last transfer\(hyprohibited message was
transmitted, no transfer\(hyprohibited messages will be sent via the Response
Method (criterion\ iii) above) referring to that destination.
.PP
Examples of the above situation appear in Recommendation\ Q.705.
.RT
.PP
13.2.3
When a signalling point receives a transfer\(hyprohibited message
from signalling transfer point\ Y it performs the actions specified in \(sc\ 7
(since reception of transfer\(hyprohibited message indicates the unavailability 
of the concerned signalling route, see \(sc\ 3.4.1). In other words, it 
may perform 
forced re\(hyrouting and, if appropriate, generate additional transfer\(hyprohibited 
messages. 
.sp 9p
.RT
.PP
13.2.4
In some circumstances it may happen that a signalling point
receives either a repeated transfer\(hyprohibited message relating to a
nonexistent route (i.e.\ there is no route from that signalling point to the
concerned destination via signalling transfer point\ Y, according to the
signalling network configuration) or to a destination which is already
inaccessible, due to previous failures; in this case no actions are taken.
.sp 2P
.LP
13.3
	\fITransfer allowed\fR 
.sp 1P
.RT
.PP
13.3.1
The transfer\(hyallowed procedure is performed at a signalling
point, acting as signalling transfer point for messages relating to a given
destination, when it has to notify one or more adjacent signalling points 
that they may start to route to it, if appropriate, the concerned 
messages.
.sp 9p
.RT
.PP
The transfer\(hyallowed procedure makes use of the transfer\(hyallowed 
message which contains: 
.LP
	\(em
	the label, indicating the destination and originating
points;
.LP
	\(em
	the transfer\(hyallowed signal; and
.LP
	\(em
	the destination for which transfer is now possible.
.bp
.PP
The format and code of these messages appear in \(sc\ 15.
.PP
Transfer allowed messages are always addressed to an adjacent
signalling point. They may use any available signalling route that leads to
that signalling point.
.FS
The possibility of referring to a more general
destination than a single signalling point (e.g.\ a signalling region), or a
more restrictive destination than a single signalling point is
for further study.
.FE
.RT
.PP
13.3.2
A transfer\(hyallowed message relating to a given destination\ \*QX\*U 
is sent from signalling transfer point\ \*QY\*U in the following cases: 
.sp 9p
.RT
.LP
	i)
	When signalling transfer point \*QY\*U stops routing (at
changeback or controlled rerouting) signalling traffic destined to signalling 
point\ \*QX\*U via a signalling transfer point\ \*QZ\*U (to which the concerned 
traffic was previously diverted as a consequence of changeover or forced 
rerouting). In this case the transfer\(hyallowed message is sent to signalling 
transfer 
point\ \*QZ\*U.
.LP
	ii)
	When signalling transfer point \*QY\*U recognizes that it is
again able to transfer signalling traffic destined to signalling point\ 
\*QX\*U (see \(sc\(sc\ 6.2.3 and\ 8.2.3). In this case a transfer\(hyallowed 
message is sent to all 
accessible adjacent signalling points. (Broadcast method).
.PP
Examples of the above situations appear in Recommendation\ Q.705.
.PP
13.3.3
When a signalling point receives a transfer\(hyallowed message
from signalling transfer point\ \*QY\*U, it performs the actions specified 
in \(sc\ 8 
(since reception of a transfer\(hyallowed message indicates the availability of
the concerned signalling route, (see \(sc\ 3.4.2)). In other words, it 
may perform controlled re\(hyrouting and, if appropriate, generate additional 
transfer\(hyallowed messages. 
.sp 9p
.RT
.PP
13.3.4
In some circumstances it may happen that a signalling point
receives either a repeated transfer\(hyallowed message or a transfer\(hyallowed
message relating to a non\(hyexistent signalling route (i.e.\ there is no route
from that signalling point to the concerned destination via signalling 
transfer point\ Y according to the signalling network configuration); in 
this case no 
actions are taken.
.sp 2P
.LP
13.4
	\fITransfer\(hyrestricted (National option)\fR 
.sp 1P
.RT
.PP
13.4.1
The transfer restricted procedure is performed at a signalling
point acting as a signalling transfer point for messages relating to a given
destination, when it has to notify one or more adjacent signalling points 
that they should, if possible, no longer route the concerned messages via 
the 
signalling transfer point.
.sp 9p
.RT
.PP
The transfer\(hyrestricted procedure makes use of the
transfer\(hyrestricted message which contains:
.LP
	\(em
	the label, indicating the destination and originating points;
.LP
	\(em
	the transfer\(hyrestricted signal, and
.LP
	\(em
	the destination for which traffic is no longer
desirable.
.PP
Formats and codes of this message appear in \(sc 15.
.PP
Transfer restricted messages are always adressed to an adjacent
signalling point. They may use any available signalling route that leads to
that signalling point.
.PP
\fINote\fR \ \(em\ Undesirable situations result in increased signalling 
delays, possibly overloading portions of the network. These inefficiencies 
could be 
avoided if the traffic can be appropriately diverted.
.RT
.PP
13.4.2
A transfer\(hyrestricted message relating to a given
destination \*QX\*U is sent from a signalling transfer point\ \*QY\*U when 
the normal 
link set (combined link set) used by signalling point\ \*QY\*U to route to
destination\ \*QX\*U experiences a long\(hyterm failure such as an equipment 
failure, or there is congestion on an alternate link set currently being 
used to 
destination\ \*QX\*U. In this case, a transfer\(hyrestricted message is 
sent to all 
accessible adjacent signalling points.
.sp 9p
.RT
.PP
When an adjacent signalling point \*QX\*U becomes accessible,
the STP \*QY\*U sends to\ \*QX\*U transfer\(hyrestricted messages concerning 
destinations that are restricted from\ \*QY\*U (see \(sc\ 9). 
.PP
When a signalling point Y restarts, it broadcasts to all accessible
adjacent signalling points transfer restricted messages concerning destinations 
restricted from\ \*QY\*U (see \(sc\ 9). 
.PP
\fINote\fR \ \(em\ Characterization of long term failure remains for further
study.
.bp
.RT
.PP
13.4.3
When a signalling point receives a transfer\(hyrestricted message
from signalling transfer point\ \*QY\*U and has an alternative equal priority 
link set available and not restricted to destination\ \*QX\*U, it performs 
the actions in \(sc\ 8.2. In other words, it performs controlled rerouting 
to maintain the 
sequence of messages while diverting them to the alternative link set. If it
cannot perform alternate routing to destination\ \*QX\*U because no alternative 
link set is available, it may generate additional transfer\(hyrestricted 
messages. 
.sp 9p
.RT
.PP
13.4.4
In some circumstances, it may happen that a signalling point
receives either a repeated transfer\(hyrestricted message or a transfer\(hyrestricted 
message relating to a non\(hyexistent route (i.e.\ there is no route from 
that 
signalling point to the concerned destination via signalling transfer
point\ \*QY\*U, according to the signalling network configuration); in 
this case, no actions are taken. 
.PP
13.4.5
When a transfer\(hyrestricted message is received updating a
transfer\(hyprohibited status, signalling traffic management decides if an
alternative route is available or restricted; if it is not (i.e.\ no alternative 
route exists), the concerned traffic is restarted towards the signalling 
point from which the transfer\(hyrestricted message was received. Otherwise, 
no other 
actions are taken.
.sp 2P
.LP
13.5
	\fISignalling\(hyroute\(hyset\(hytest\fR 
.sp 1P
.RT
.PP
13.5.1
The signalling\(hyroute\(hyset\(hytest procedure is used at a signalling
point to test whether or not signalling traffic towards a certain destination 
may be routed via an adjacent signalling transfer point. 
.sp 9p
.RT
.PP
The procedure makes use of the signalling\(hyroute\(hyset\(hytest message, 
and the transfer\(hyallowed and the transfer\(hyprohibited procedures. 
.PP
The signalling\(hyroute\(hyset\(hytest message contains:
.RT
.LP
	\(em
	the label, indicating the destination and originating
points;
.LP
	\(em
	the signalling\(hyroute\(hyset\(hytest signal;
.LP
	\(em
	the destination, the accessibility of which is to be tested;  and
.LP
	\(em
	the current route status of the destination being
tested.
.FS
The possibility of referring to a more general destination than a single 
signalling point (e.g.\ a signalling region), or a more restrictive 
destination than a single signalling point is
for further study.
.FE
.PP
Format and coding of this message appear in \(sc\ 15.
.PP
13.5.2
A signalling\(hyroute\(hyset\(hytest message is sent from a signalling
point after a transfer\(hyprohibited or transfer\(hyrestricted
message is received from an adjacent signalling transfer point. In this 
case, a signalling\(hyroute\(hyset\(hytest message is sent to that signalling 
transfer point 
referring to the destination declared inaccessible or restricted by the
transfer\(hyprohibited or transfer\(hyrestricted
message, every\ T10
period (see \(sc\ 16) until a transfer\(hyallowed message, indicating that the
destination has become accessible, is received.
.sp 9p
.RT
.PP
This procedure is used in order to recover the signalling route
availability information that may not have been received because of some
signalling network failure.
.PP
13.5.3
A signalling\(hyroute\(hyset\(hytest message is sent to the adjacent
signalling transfer point as an ordinary signalling network management
message.
.sp 9p
.RT
.PP
13.5.4
At the reception of a signalling\(hyroute\(hyset\(hytest message, a
signalling transfer point will compare the status of the destination in the
received message with the actual status of the destination. If they are the
same, no further action is taken. If they are different, one of the following 
messages is sent in response, dictated by the actual status of the 
destination:
.LP
	\(em
	 a transfer\(hyallowed message, referring to the destination the accessibility 
of which is tested, if the signalling transfer point can reach 
the indicated destination via a signalling link not connected to the signalling 
point from which the signalling\(hyroute\(hyset\(hytest message was originated, 
and via the normal routing; 
.LP
	\(em
	a transfer\(hyrestricted
message when access
to the destination is possible via an alternative to the normal routing 
which is less efficient, but still not via the signalling point from which 
the 
signalling route\(hyset\(hytest was originated;
.LP
	\(em
	 a transfer\(hyprohibited message in all other cases (including the inaccessibility 
of that destination). 
.bp
.PP
13.5.5
At the reception of the transfer\(hyprohibited or transfer\(hyallowed
message, the signalling point will perform the procedures specified in
\(sc\(sc\ 13.2.3 or\ 13.2.4 and\ 13.3.3 or\ 13.3.4 respectively.
.sp 9p
.RT
.sp 1P
.LP
13.6
	\fITransfer controlled (International network)\fR 
.sp 9p
.RT
.PP
The only use made of the transfer controlled procedure in the
international signalling network is to convey the congestion indication from
the\ SP where congestion was detected to the originating\ SP (see \(sc\ 
11.2.3) in a transfer\(hycontrolled message. 
.PP
The transfer\(hycontrolled message contains:
.RT
.LP
	\(em
	the label, indicating the destination and originating
points;
.LP
	\(em
	the transfer controlled signal;
.LP
	\(em
	the identity of the congested destination.
.PP
The format and coding of the transfer controlled message appear in \(sc\ 15.
.sp 2P
.LP
13.7
	\fITransfer controlled (National option with congestion\fR 
\fIpriorities)\fR 
.sp 1P
.RT
.PP
13.7.1
The transfer\(hycontrolled procedure is performed at a signalling
transfer point for messages relating to a given destination, when it has to
notify one or more originating signalling points that they should no longer
send to the concerned destination messages with a given priority or lower.
.sp 9p
.RT
.PP
The transfer\(hycontrolled procedure makes use of the
transfer\(hycontrolled message which contains:
.LP
	\(em
	the label, indicating the destination and originating
points,
.LP
	\(em
	the transfer\(hycontrolled signal,
.LP
	\(em
	 the destination for which messages with a congestion priority lower than 
the specified congestion status should no longer be sent, and 
.LP
	\(em
	the current congestion status encountered in routing a
particular message towards the concerned destination.
.PP
The format and coding of this message appear in \(sc\ 15.
.PP
13.7.2
A transfer\(hycontrolled message relating to a given destination \*QX\*U 
is sent from a signalling transfer point\ \*QY\*U in response to a received 
message originating from signalling point\ \*QZ\*U destined to signalling 
point\ \*QX\*U when the congestion priority of the concerned message is 
less than the current 
congestion status of the signalling link selected to transmit the concerned
message from\ \*QY\*U to\ \*QX\*U.
.sp 9p
.RT
.PP
In this case, the transfer\(hycontrolled message is sent to the
originating point\ \*QZ\*U with the congestion status field set to the current
congestion status of the signalling link.
.PP
13.7.3
When the originating signalling points \*QZ\*U receive a
transfer\(hycontrolled message relating to destination\ \*QX\*U, if the current
congestion status of the signalling route set towards destination\ \*QX\*U 
is less than the congestion status in the transfer\(hycontrolled message, 
it updates the congestion status of the signalling route set towards destination\ 
\*QX\*U with the value of the congestion status carried in the transfer\(hycontrolled 
message.
.sp 9p
.RT
.PP
13.7.4
If within T15 (see \(sc\ 16) after the receipt of the last
transfer\(hycontrolled message relating to destination\ \*QX\*U, signalling 
point\ \*QZ\*U receives another transfer\(hycontrolled message relating 
to the same destination, the following action is taken: If the value of 
the congestion status carried in the new transfer\(hycontrolled message 
is greater than the current value of the 
congestion status of the signalling route set towards destination\ \*QX\*U, 
then the current value is updated by the new value. 
.PP
13.7.5
If T15 (see \(sc\ 16) expires after the last update of the signalling
route set towards destination\ \*QX\*U by a transfer\(hycontrolled message 
relating to the same destination, the signalling\(hyroute\(hyset\(hycongestion\(hytest 
procedure is 
invoked (see \(sc\ 13.9).
.PP
13.7.6
In some circumstances it may happen that a signalling point
receives a transfer\(hycontrolled message relating to a destination which is
already inaccessible due to previous failures; in this case the
transfer\(hycontrolled message is ignored.
.bp
.sp 1P
.LP
13.8
	\fITransfer controlled (National option without congestion\fR 
\fIpriorities)\fR 
.sp 9p
.RT
.PP
The only use made of the TFC procedure by the national signalling network, 
using multiple congestion states without congestion priorities, is to convey 
the congestion indication primitive from the\ SP where congestion was 
detected to the originating\ SP (see \(sc\ 11.2.5) in a transfer\(hycontrolled
message.
.PP
The transfer\(hycontrolled message contains:
.RT
.LP
	\(em
	the label, indicating the destination and originating
points;
.LP
	\(em
	the transfer\(hycontrolled signal;
.LP
	\(em
	the identity of the congested destination;
.LP
	\(em
	the current congestion status encountered in routing a
particular message towards the concerned destination.
.PP
The format and coding of this message appear in \(sc\ 15.
.sp 2P
.LP
13.9
	\fISignalling\(hyroute\(hyset\(hycongestion\(hytest (National Option)\fR 
.sp 1P
.RT
.PP
13.9.1
The signalling\(hyroute\(hyset\(hycongestion\(hytest procedure is used at
an originating signalling point to update the congestion status associated 
with a route set towards a certain destination. The purpose is to test 
whether or 
not signalling messages destined towards that destination with a given
congestion priority or higher may be sent.
.sp 9p
.RT
.PP
In the case of a processor restart the congestion status of all
signalling route sets will be initialized to the zero value. The response
mechanism within the transfer\(hycontrolled procedure will correct signalling
route sets whose congestion status does not have the zero value.
.PP
The procedure makes use of the signalling\(hyroute\(hyset\(hycongestion\(hytest
message, and the transfer\(hycontrolled procedure.
.PP
The signalling\(hyroute\(hyset\(hycongestion\(hytest message contains:
.RT
.LP
	\(em
	the label, indicating the destination and originating points, and
.LP
	\(em
	the signalling\(hyroute\(hyset\(hycongestion\(hytest signal.
.PP
The format and coding of this message appear in \(sc\ 15.
.PP
13.9.2
The signalling\(hyroute\(hyset\(hycongestion\(hytest message differs from
other signalling network management messages in that it is not assigned the
highest congestion priority. Instead, the congestion priority assigned to a
signalling\(hyroute\(hyset\(hycongestion\(hytest message to be sent to 
a given destination is equal to one less than the current congestion status 
associated with the 
signalling route set towards the destination.
.sp 9p
.RT
.PP
13.9.3
If within T16 (see \(sc\ 16), after sending a
signalling\(hyroute\(hyset\(hycongestion\(hytest message, a transfer\(hycontrolled 
message 
relating to the concerned destination is received, the signalling point 
updates the congestion status of the signalling route set towards the concerned 
destination with the value of the congestion status carried in the
transfer\(hycontrolled message. Following this, the procedures specified in
\(sc\(sc\ 13.9.4 and\ 13.9.5 are performed.
.PP
If T16 (see \(sc\ 16) expires after sending a
signalling\(hyroute\(hyset\(hycongestion\(hytest
message without a transfer\(hycontrolled message
relating to the concerned destination having been received, the signalling
point changes the congestion status associated with the signalling route set
towards the concerned destination to the next lower status.
.PP
13.9.4
Provided that the signalling route set towards destination\ \*QX\*U is 
not in the \*Qunavailable\*U state, a signalling\(hyroute\(hyset\(hycongestion\(hytest 
message is sent from an originating signalling point to destination\ \*QX\*U 
in the 
following cases:
.sp 9p
.RT
.LP
	i)
	When T15 (see \(sc\ 16) expires after the last update of the
congestion status of the signalling route set toward destination\ \*QX\*U by a
transfer\(hycontrolled message relating to the same destination.
.LP
	ii)
	When T16 (see \(sc\ 16) expires after sending a
signalling\(hyroute\(hyset\(hycongestion\(hytest message to destination\ 
\*QX\*U without a 
transfer\(hycontrolled message relating to the same destination having been
received. After the congestion status has been decremented by one, the 
test is repeated, unless the congestion status is zero. 
.bp
.PP
13.9.5
At the reception of a signalling\(hyroute\(hyset\(hycongestion\(hytest
message, a signalling transfer point will route it as an ordinary message,
i.e.\ according to the procedure specified in \(sc\ 2.3.5.
.sp 9p
.RT
.PP
13.9.6
When a signalling\(hyroute\(hyset\(hycongestion\(hytest message reaches its
destination, it is discarded.
.sp 2P
.LP
\fB14\fR 	\fBCommon characteristics of message signal unit formats\fR 
.sp 1P
.RT
.sp 1P
.LP
14.1
	\fIGeneral\fR 
.sp 9p
.RT
.PP
The basic signal unit format which is common to all message signal units 
is described in Recommendation\ Q.703, \(sc\ 2. From the point of view 
of the Message Transfer Part level\ 3 functions, common characteristics 
of the message signal units are the presence of: 
.RT
.LP
	\(em
	the service information octet;
.LP
	\(em
	the label, contained in the signalling information field,
and, in particular, the routing label.
.sp 1P
.LP
14.2
	\fIService information octet\fR 
.sp 9p
.RT
.PP
The service information octet of message signal units contains the service 
indicator and the sub\(hyservice field. The structure of the service 
information octet is shown in Figure\ 13/Q.704.
.RT
.LP
.rs
.sp 10P
.ad r
\fBFigure 13/Q.704, p.\fR 
.sp 1P
.RT
.ad b
.RT
.sp 1P
.LP
14.2.1
	\fIService indicator\fR 
.sp 9p
.RT
.PP
The service indicator is used by signalling handling functions to perform 
message distribution (see \(sc\ 2.4) and, in some special applications, 
to perform message routing (see \(sc\ 2.3). 
.PP
The service indicator codes \fIfor the international signalling\fR 
\fInetwork\fR are allocated as follows:
.RT
.LP
	bits
	D
	C
	B
	A
.LP
	0
	0
	0
	0
	\ Signalling network management messages
.LP
	0
	0
	0
	1
	\ Signalling network testing and maintenance
messages
.LP
	0
	0
	1
	0
	\ Spare
.LP
	0
	0
	1
	1
	\ SCCP
.LP
	0
	1
	0
	0
	\ Telephone User Part
.LP
	0
	1
	0
	1
	\ ISDN User Part
.LP
	0
	1
	1
	0
	\ Data User Part (call and circuit related
messages)
.LP
	0
	1
	1
	1
	\ Data User Part (facility registration and
cancellation messages)
.LP
	1
	0
	0
	0
	\ Reserved for MTP Testing User Part
.LP
	1
	0
	0
	1
	
.LP
	1
	0
	1
	0
	
.LP
	1
	0
	1
	1
	
.LP
	1
	1
	0
	0
	\ spare
.LP
	1
	1
	0
	1
	
.LP
	1
	1
	1
	0
	
.LP
	1
	1
	1
	1
	.bp
.PP
The allocation of the service indicator codes for national
signalling networks is a national matter. However, it is suggested to allocate 
the same service indicator code to a User Part which performs similar functions 
as in the international network. 
.sp 1P
.LP
14.2.2
	\fISub\(hyservice field\fR 
.sp 9p
.RT
.PP
The sub\(hyservice field contains the network indicator (bits\ C and\ D) 
and two spare bits (bits\ A and\ B). 
.PP
The \fInetwork\fR  | ndicator is used by signalling message handling
functions (e.g., in order to determine the relevant version of a User Part),
see \(sc\(sc\ 2.3 and\ 2.4.
.PP
If the network indicator is set to 00 or 01, the two spare bits,
coded\ 00, are available for possible future needs that may require a common
solution for all international User Parts.
.PP
If the network indicator is set to 10 or 11, the two spare bits are
for national use. They may be used, for example, to indicate message priority, 
which is used in the optional flow control procedure in national applications. 
.PP
The network indicator provides for discrimination between
international and national messages. It can also be used, for example, 
for the discrimination between functionally two national signalling networks, 
each 
having different routing label structures and including up to\ 16 User Parts
defined by the\ 16 possible codes of the service indicator.
.PP
In the case of only one national signalling network the spare code of the 
network indicator reserved for national use can be used, for example, to 
define an additional\ 16 User Parts (making a total of\ 32 User Parts) 
for that national signalling network. 
.PP
The network indicator codes are allocated as follows:
.RT
.LP
	bits
	D
	C
.LP
	0
	0
	International network
.LP
	0
	1
	Spare (for international use only)
.LP
	1
	0
	National network
.LP
	1
	1
	Reserved for national use
.PP
The international spare code (01) should not be used for
implementing features which are to be provided both internationally and
nationally.
.PP
In national applications, when the discrimination provided by the
network indicator between international and national messages is not used,
i.e.\ in a closed national signalling network seen from the signalling 
point of view, the whole sub\(hyservice field can be used independently 
for different User Parts. 
.RT
.sp 1P
.LP
14.3
	\fILabel\fR 
.sp 9p
.RT
.PP
The structure and content of the label is defined for each User
Part and is defined in the relevant specification. The common part of the 
label used for signalling message handling, the routing label, is specified 
in 
\(sc\ 2.2.
.RT
.LP
\fB15\fR 	\fBFormats and codes of signalling network management\fR 
\fBmessages\fR 
.sp 1P
.RT
.sp 2P
.LP
15.1
	\fIGeneral\fR 
.sp 1P
.RT
.PP
15.1.1
The signalling network management messages are carried on the
signalling channel in message signal units, the format of which is described 
in \(sc\ 14 and in Recommendation\ Q.703, \(sc\ 2. In particular, as indicated 
in \(sc\ 14.2 
these messages are distinguished by the configuration\ 0000 of the service
indicator (SI). The sub\(hyservice field (SSF) of the messages is used 
according to the rules indicated in \(sc\ 14.2.2. 
.sp 9p
.RT
.PP
15.1.2
The signalling information field consists of an integral number of octets 
and contains the label, the heading code and one or more signals and 
indications. The structure and function of the label, and of the heading 
code, are described in \(sc\(sc\ 15.2 and\ 15.3 respectively; the detailed 
message formats 
are described in the following sections. For each message the sequence of
fields is shown in the corresponding figure, including fields that may 
or may not be present. 
.bp
.PP
In the figures, the fields are shown starting from the right to
the left (i.e. the first field to be transmitted is at the right). Within 
each field the information is transmitted least significant bit first. 
Spare bits 
are coded 0\ unlesss otherwise indicated.
.sp 1P
.LP
15.2
	\fILabel\fR 
.sp 9p
.RT
.PP
For signalling network management messages the label coincides with the 
routing label and indicates the destination and originating signalling 
points of the message; moreover, in the case of messages related to a
particular signalling link, it also indicates the identity of the signalling
link among those interconnecting the destination and originating points. The
standard label structure of Message Transfer Part level\ 3 messages appears 
in Figure\ 14/Q.704; the total length is 32\ bits. 
.RT
.LP
.rs
.sp 15P
.ad r
\fBFigure 14/Q.704, p.\fR 
.sp 1P
.RT
.ad b
.RT
.PP
The meaning and use of the destination point code (DPC) and of the originating 
point code (OPC) fields are described in \(sc\ 2. The signalling link code 
(SLC) indicates the signalling link, connecting the destination and 
originating points, to which the message is related. If the message is not
related to a signalling link, or another particular code is not specified, 
it is coded\ 0000. 
.sp 1P
.LP
15.3
	\fIHeading code (H0)\fR 
.sp 9p
.RT
.PP
The heading code (H0) is the 4 bit field following the label and
identifies the message group.
.PP
The different heading codes are allocated as follows:
.RT
.LP
	0000
	Spare
.LP
	0001
	Changeover and changeback messages
.LP
	0010
	Emergency changeover message
.LP
	0011
	Transfer controlled and signalling route set congestion
messages
.LP
	0100
	Transfer\(hyprohibited\(hyallowed\(hyrestricted messages
.LP
	0101
	Signalling\(hyroute\(hyset\(hytest messages
.LP
	0110
	Management inhibit messages
.LP
	0111
	Traffic restart allowed message
.LP
	1000
	Signalling\(hydata\(hylink\(hyconnection messages
.LP
	1001
	Spare
.LP
	1010
	User part flow control messages
.PP
The remaining codings are spare.
.PP
The synopsis of singalling network management messages is given in
Table\ 1/Q.704.
.bp
.RT
.sp 2P
.LP
15.4
	\fIChangeover message\fR 
.sp 1P
.RT
.PP
15.4.1
The format of the changeover message is shown in Figure\ 15/Q.704.
.sp 9p
.RT
.LP
.rs
.sp 9P
.ad r
\fBFigure 15/Q.704, p.\fR 
.sp 1P
.RT
.ad b
.RT
.PP
15.4.2
The changeover message is made up of the following fields:
.LP
	\(em
	Label (32 bits): see \(sc\ 15.2
.LP
	\(em
	Heading code H0 (4 bits): see \(sc\ 15.3
.LP
	\(em
	Heading code H1 (4 bits): see \(sc\ 15.4.3
.LP
	\(em
	Forward sequence number of last accepted message signal unit
(7 bits)
.LP
	\(em
	A filler bit coded 0
.PP
15.4.3
The heading code H1 contains signal codes as follows:
.sp 9p
.RT
.LP
	bit
	D
	C
	B
	A
.LP
	0
	0
	0
	1
	Changeover order signal
.LP
	0
	0
	1
	0
	Changeover acknowledgement
signal
.sp 2P
.LP
15.5
	\fIChangeback message\fR 
.sp 1P
.RT
.PP
15.5.1
The format of the changeback message is shown in Figure\ 16/Q.704.
.sp 9p
.RT
.LP
.rs
.sp 10P
.ad r
\fBFigure 16/Q.704, p.\fR 
.sp 1P
.RT
.ad b
.RT
.PP
15.5.2
The changeback message is made up of the following fields:
.LP
	\(em
	Label (32 bits) see \(sc\ 15.2
.LP
	\(em
	Heading code H0 (4 bits): see \(sc\ 15.3
.LP
	\(em
	Heading code H1 (4 bits): see \(sc\ 15.5.3
.LP
	\(em
	Changeback code (8 bits): see \(sc\ 15.5.4
.bp
.PP
15.5.3
The header code H1 contains signal codes as follows:
.sp 9p
.RT
.LP
	bit
	D
	C
	B
	A
.LP
	0
	1
	0
	1
	Changeback declaration signal
.LP
	0
	1
	1
	0
	Changeback acknowledgement
signal
.PP
15.5.4
The changeback code is an 8 bit code assigned by the signalling point which 
sends the message according to the criteria described in \(sc\ 6. 
.sp 9p
.RT
.sp 2P
.LP
15.6
	\fIEmergency changeover message\fR 
.sp 1P
.RT
.PP
15.6.1
The format of the emergency changeover message is shown in
Figure 17/Q.704.
.sp 9p
.RT
.LP
.rs
.sp 10P
.ad r
\fBFigure 17/Q.704, p.\fR 
.sp 1P
.RT
.ad b
.RT
.PP
15.6.2
The emergency changeover message is made up of the following
fields:
.LP
	\(em
	Label (32 bits): see \(sc\ 15.2
.LP
	\(em
	Heading code H0 (4 bits): see \(sc\ 15.3
.LP
	\(em
	Heading code H1 (4 bits): see \(sc\ 15.6.3
.PP
15.6.3
The header code H1 contains signal codes as follows:
.sp 9p
.RT
.LP
	bit
	D
	C
	B
	A
.LP
	0
	0
	0
	1
	Emergency changeover order signal
.LP
	0
	0
	1
	0
	Emergency changeover acknowledgement signal
.sp 2P
.LP
15.7
	\fITransfer\(hyprohibited message\fR 
.sp 1P
.RT
.PP
15.7.1
The format of the transfer\(hyprohibited message is shown in
Figure\ 18/Q.704.
.sp 9p
.RT
.LP
.rs
.sp 10P
.ad r
\fBFigure 18/Q.704, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.PP
15.7.2
The transfer\(hyprohibited message is made up of the following
fields:
.LP
	\(em
	Label (32 bits): see \(sc\ 15.2
.LP
	\(em
	Heading code H0 (4 bits): see \(sc\ 15.3
.LP
	\(em
	Heading code H1 (4 bits): see \(sc\ 15.7.3
.LP
	\(em
	Destination (14 bits): see \(sc\ 15.7.4
.LP
	\(em
	Spare bits (2 bits) code 00
.PP
15.7.3
The heading code H1 contains one signal code as follows:
.sp 9p
.RT
.LP
	bit
	D
	C
	B
	A
.LP
	0
	0
	0
	1
	Transfer\(hyprohibited signal
.PP
15.7.4
The destination field contains the identity of the signalling
point to which the message refers.
.sp 9p
.RT
.sp 2P
.LP
15.8
	\fITransfer\(hyallowed message\fR 
.sp 1P
.RT
.PP
15.8.1
The format of the transfer\(hyallowed message is shown in
Figure\ 19/Q.704.
.sp 9p
.RT
.LP
.rs
.sp 10P
.ad r
\fBFigure 19/Q.704, p.\fR 
.sp 1P
.RT
.ad b
.RT
.PP
15.8.2
The transfer\(hyallowed message is made up of the following
fields:
.LP
	\(em
	Label (32 bits): see \(sc\ 15.2
.LP
	\(em
	Heading code H0 (4 bits): see \(sc\ 15.3
.LP
	\(em
	Heading code H1 (4 bits): see \(sc\ 15.8.3
.LP
	\(em
	Destination (14 bits): see \(sc\ 15.7.4
.LP
	\(em
	Spare bits (2 bits) coded 00
.PP
\fINote\fR \ \(em\ For the use of the 2 spare bits in the national option
for a SIF compatibility mechanism, see Recommendation\ Q.701, \(sc\ 7.2.6.
.PP
15.8.3
The heading code H1 contains one signal code as follows:
.sp 9p
.RT
.LP
	bit
	D
	C
	B
	A
.LP
	0
	1
	0
	1
	Transfer\(hyallowed signal
.sp 2P
.LP
15.9
	\fITransfer restricted message (national option)\fR 
.sp 1P
.RT
.PP
15.9.1
The format of the transfer restricted message is shown in
Figure\ 18/Q.704.
.sp 9p
.RT
.PP
15.9.2
The transfer restricted message is made up of the following
fields:
.LP
	\(em
	Label (32 bits): see \(sc\ 15.2
.LP
	\(em
	Heading code H0 (4 bits): see \(sc\ 15.3
.LP
	\(em
	Heading code H1 (4 bits): see \(sc\ 15.9.3
.LP
	\(em
	Destination (14 bits): see \(sc\ 15.9.4
.LP
	\(em
	Spare (2 bits) coded 00
.bp
.PP
15.9.3
The heading code H1 contains one signal code as follows:
.sp 9p
.RT
.LP
	bit
	D
	C
	B
	A
.LP
	0
	0
	1
	1
	Transfer restricted
.PP
15.9.4
The destination field contains the identity of the signalling point to 
which the message refers. 
.sp 9p
.RT
.sp 2P
.LP
15.10
	\fISignalling\(hyroute\(hyset\(hytest message\fR 
.sp 1P
.RT
.sp 1P
.LP
15.10.1\ \ The format of the signalling\(hyroute\(hyset\(hytest message 
is shown in 
Figure\ 20/Q.704.
.sp 9p
.RT
.LP
.rs
.sp 10P
.ad r
\fBFigure 20/Q.704, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
15.10.2\ \ This message is made up of the following fields:
.LP
	\(em
	Label (32 bits): see \(sc\ 15.2
.LP
	\(em
	Heading code H0 (4 bits): see \(sc\ 15.3
.LP
	\(em
	Heading code H1 (4 bits): see \(sc\ 15.10.3
.LP
	\(em
	Destination (14 bits): see \(sc\ 15.7.4
.LP
	\(em
	Spare bits (2 bits) coded 00
.sp 1P
.LP
15.10.3\ \ The heading code H1 contains signal codes as follows:
.sp 9p
.RT
.LP
	bit
	D
	C
	B
	A
.LP
	0
	0
	0
	1
	Signalling\(hyroute\(hyset\(hytest signal   for prohibited destination
.LP
	0
	0
	1
	0
	 Signalling\(hyroute\(hyset\(hytest signal for restricted destination 
(national option) 
.sp 2P
.LP
15.11
	\fIManagement inhibit message\fR 
.sp 1P
.RT
.sp 1P
.LP
15.11.1\ \ The format of the management inhibit message is shown in
Figure\ 20a/Q.704.
.sp 9p
.RT
.LP
.rs
.sp 11P
.ad r
\fBFigure 20a/Q.704, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
15.11.2\ \ The management inhibit message is made up of the following
fields:
.LP
	\(em
	Label (32 bits): see \(sc\ 15.2
.LP
	\(em
	Heading code H0 (4 bits): see \(sc\ 15.3
.LP
	\(em
	Heading code H1 (4 bits): see \(sc\ 15.11.3
.sp 1P
.LP
15.11.3\ \ The header code H1 contains signal codes as follows:
.sp 9p
.RT
.LP
	bit
	D
	C
	B
	A
.LP
	0
	0
	0
	1
	Link inhibit signal
.LP
	0
	0
	1
	0
	Link uninhibit signal
.LP
	0
	0
	1
	1
	Link inhibited acknowledgement
signal
.LP
	0
	1
	0
	0
	Link uninhibited acknowledgement   signal
.LP
	0
	1
	0
	1
	Link inhibit denied signal
.LP
	0
	1
	1
	0
	Link force uninhibit signal
.LP
	0
	1
	1
	1
	Link local inhibit test signal
.LP
	1
	0
	0
	0
	Link remote inhibit test
signal
.sp 2P
.LP
15.12
	\fITraffic restart allowed message\fR 
.sp 1P
.RT
.sp 1P
.LP
15.12.1\ \ The format of the traffic restart allowed message is shown in
Figure\ 21/Q.704.
.sp 9p
.RT
.LP
.rs
.sp 9P
.ad r
\fBFigure 21/Q.704, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
15.12.2\ \ The traffic restart allowed message is made up of the following
fields:
.LP
	\(em
	Label (32 bits): see \(sc\ 15.2
.LP
	\(em
	Heading code H0 (4 bits): see \(sc\ 15.3
.LP
	\(em
	Heading code H1 (4 bits): see \(sc\ 15.12.3
.sp 1P
.LP
15.12.3\ \ The heading code H1 contains one signal code as follows:
.sp 9p
.RT
.LP
	bit
	D
	C
	B
	A
.LP
	0
	0
	0
	1
	Traffic restart allowed
signal
.sp 2P
.LP
15.13
	\fISignalling\(hydata\(hylink\(hyconnection\(hyorder message\fR 
.sp 1P
.RT
.sp 1P
.LP
15.13.1\ \ The format of the signalling\(hydata\(hylink\(hyconnection\(hyorder 
message 
is shown in Figure\ 22/Q.704.
.sp 9p
.RT
.LP
.rs
.sp 9P
.ad r
\fBFigure 22/Q.704, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
15.13.2\ \ The signalling\(hydata\(hylink\(hyconnection\(hyorder message 
is made up of 
the following fields:
.LP
	\(em
	Label (32 bits): see \(sc\ 15.2
.LP
	\(em
	Heading code H0 (4 bits): see \(sc\ 15.3
.LP
	\(em
	Heading code H1 (4 bits): see \(sc\ 15.13.3
.LP
	\(em
	Signalling data link identity (12 bits): see \(sc\ 15.13.4
.LP
	\(em
	Spare bits (4 bits) coded 0000.
.sp 1P
.LP
15.13.3\ \ The heading code H1 contains one signal code as follows:
.sp 9p
.RT
.LP
	bit
	D
	C
	B
	A
.LP
	0
	0
	0
	1
	Signalling\(hydata\(hylink\(hyconnection\(hyorder
signal
.sp 1P
.LP
15.13.4\ \ The signalling data link identity field contains the circuit
identification code (CIC), or the bearer identification code (BIC) in case 
of a 64\ kbit/s channel used to carry submultiplex data streams, of the 
transmission link corresponding to the signalling data link. 
.sp 9p
.RT
.sp 2P
.LP
15.14
	\fISignalling\(hydata\(hylink\(hyconnection\(hyacknowledgement message\fR 
.sp 1P
.RT
.sp 1P
.LP
15.14.1\ \ The format of the signalling\(hydata\(hylink\(hyconnection\(hyacknowledgement 
message is shown in Figure 
22a/Q.704.
.sp 9p
.RT
.LP
.rs
.sp 20P
.ad r
\fBFigure 22a/Q.704, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
15.14.2\ \ The signalling\(hydata\(hylink\(hyconnection acknowledgement 
message is made 
up of the following fields:
.LP
	\(em
	Label (32 bits): see \(sc\ 15.2
.LP
	\(em
	Heading code H0 (4 bits): see \(sc\ 15.3
.LP
	\(em
	Heading code H1 (4 bits): see \(sc\ 15.14.3
.sp 1P
.LP
15.14.3\ \ The heading code H1 contains signal codes as follows:
.sp 9p
.RT
.LP
	bit
	D
	C
	B
	A
.LP
	0
	0
	1
	0
	Connection\(hysuccessful signal
.LP
	0
	0
	1
	1
	Connection\(hynot\(hysuccessful signal
.LP
	0
	1
	0
	0
	Connection\(hynot\(hypossible
signal
.bp
.sp 2P
.LP
15.15
	\fITransfer controlled message\fR 
.sp 1P
.RT
.sp 1P
.LP
15.15.1\ \ The format of the TFC message is shown in Figure 22b/Q.704.
.sp 9p
.RT
.LP
.rs
.sp 12P
.ad r
\fBFigure 22b/Q.704, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
15.15.2\ \ The transfer controlled message is made up of the following
fields:
.LP
	\(em
	Label (32 bits): see \(sc 15.2
.LP
	\(em
	Heading code H0 (4 bits): see \(sc\ 15.3
.LP
	\(em
	Heading code H1 (4 bits): see \(sc\ 15.15.3
.LP
	\(em
	Destination (14 bits): see \(sc\ 15.15.4
.LP
	\(em
	Spare (2 bits): see \(sc15.15.5
.sp 1P
.LP
15.15.3\ \ The heading code H1 contains one signal code as follows:
.sp 9p
.RT
.LP
	bit
	D
	C
	B
	A
.LP
	0
	0
	1
	0
	Transfer controlled signal
.sp 1P
.LP
15.15.4\ \ The destination field carries the address of the destination to
which the message refers.
.sp 9p
.RT
.LP
15.15.5\ \ In national signalling networks using multiple congestion states,
the spare bits in the transfer controlled message are used to carry the
congestion status associated with the destination.
.sp 2P
.LP
15.16
	\fISignalling\(hyroute\(hyset\(hycongestion\(hytest message (national\fR 
\fIoption)\fR 
.sp 1P
.RT
.sp 1P
.LP
15.16.1\ \ The format of the signalling\(hyroute\(hyset\(hycongestion\(hytest 
message 
is shown in Figure\ 22c/Q.704.
.sp 9p
.RT
.LP
.rs
.sp 11P
.ad r
\fBFigure 22c/Q.704, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
15.16.2\ \ The signalling\(hyroute\(hyset\(hycongestion test message is 
made up of 
the following fields:
.LP
	\(em
	Label (32 bits): see \(sc\ 15.2
.LP
	\(em
	Heading code H0 (4 bits): see \(sc\ 15.3
.LP
	\(em
	Heading code H1 (4 bits): see \(sc\ 15.16.3
.sp 1P
.LP
15.16.3\ \ The heading code H1 contains one signal code as follows:
.sp 9p
.RT
.LP
	bit
	D
	C
	B
	A
.LP
	0
	0
	0
	1
	Signalling\(hyroute\(hyset\(hycongestion\(hytest   signal
.sp 2P
.LP
15.17
	\fIUser part unavailable message\fR 
.sp 1P
.RT
.sp 1P
.LP
15.17.1\ \ The format of the user part unavailable message is shown in
Figure\ 22d/Q.704.
.sp 9p
.RT
.LP
.rs
.sp 9P
.ad r
\fBFigure 22d/Q.704, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
15.17.2\ \ The user part unavailable message is made up of the following
fields:
.LP
	\(em
	Label (32 bits): see \(sc\ 15.2
.LP
	\(em
	Heading code H0 (4 bits): see \(sc\ 15.3
.LP
	\(em
	Heading code H1 (4 bits): see \(sc\ 15.17.3
.LP
	\(em
	Destination (14 bits): see \(sc\ 15.15.4
.LP
	\(em
	Spare (2 bits): coded 00
.LP
	\(em
	User part identity (4 bits): see \(sc\ 15.17.4
.LP
	\(em
	Spare (4 bits) coded\ 0000
.sp 1P
.LP
15.17.3\ \ The heading code H1 contains signal codes as follows:
.sp 9p
.RT
.LP
	bit
	D
	C
	B
	A
.LP
	0
	0
	0
	1
	User part unavailable
.sp 1P
.LP
15.17.4\ \ The user part identity is coded as follows:
.sp 9p
.RT
.LP
	bit
	D
	C
	B
	A
.LP
	0
	0
	0
	0
	Spare
.LP
	0
	0
	0
	1
	Spare
.LP
	0
	0
	1
	0
	Spare
.LP
	0
	0
	1
	1
	SCCP
.LP
	0
	1
	0
	0
	TUP
.LP
	0
	1
	0
	1
	ISUP
.LP
	0
	1
	1
	0
	DUP
.LP
	0
	1
	1
	1
	Spare
.LP
	1
	0
	0
	0
	MTP Testing User Part
.LP
	1
	0
	0
	1
	\ 
.LP
	to
	\ 
\ Spare
.LP
	1
	1
	1
	1
	\ 
.bp
.LP
.ce
\fBH.T. [1T1.704]\fR 
.ce
TABLE\ 1/Q.704
.ce
\fBHeading code allocation of signalling network\fR 
.ce
\fBmanagement messages\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(24p) | lw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) .
Message Group	H1  H0	0000	0001	0010	0011  	0100	0101	0110	0111  	1000	1001	1010	1011  	1100	1101	1110	1111
_
.T&
cw(24p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) .
	0000																
_
.T&
lw(24p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) .
CHM	0001		COO	COA			CBD	CBA									
_
.T&
lw(24p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) .
ECM	0010		ECO	ECA													
_
.T&
lw(24p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) .
FCM	0011		RCT	TFC													
_
.T&
lw(24p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) .
TFM	0100		TFP	*	TFR		TFA	*									
_
.T&
lw(24p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) .
RSM	0101		RST	RSR													
_
.T&
lw(24p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) .
MIM	0110		LIN	LUN	LIA	LUA	LID	LFU	LLT	LRT							
_
.T&
lw(24p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) .
TRM	0111		TRA														
_
.T&
lw(24p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) .
DLM	1000		DLC	CSS	CNS	CNP											
_
.T&
lw(24p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) .
	1001																
_
.T&
lw(24p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) .
UFC	1010		UPU														
_
.T&
lw(24p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) .
	1011																
_
.T&
lw(24p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) .
	1100																
_
.T&
lw(24p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) .
	1101																
_
.T&
lw(24p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) .
	1110																
_
.T&
lw(24p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) | cw(12p) .
	
1111
.TE
.LP

\fINote\fR
\ \(em\ Values marked * should not be used (codes used in the Yellow Book
for TFP and TFA acknowledgement).
.LP
CBA
Changeback\(hyacknowledgement signal
.LP
CBD
Changeback\(hydeclaration signal
.LP
CHM
Changeover and changeback messages
.LP
CNP
Connection\(hynot\(hypossible signal
.LP
CNS
Connection\(hynot\(hysuccessful signal
.LP
COA
Changeover\(hyacknowledgement signal
.LP
COO
Changeover\(hyorder signal
.LP
CSS
Connection\(hysuccessful signal
.LP
DLC
Signalling\(hydata\(hylink\(hyconnection\(hyorder signal
.LP
DLM
Signalling\(hydata\(hylink\(hyconnection\(hyorder message
.LP
ECA
Emergency\(hychangeover\(hyacknowledgement signal
.LP
ECM
Emergency\(hychangeover message
.nr PS 9
.RT
.ad r
\fBTable 1/Q.704 + Notes [1T1.704], p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.ce
\fBH.T. [2T1.704]\fR 
.LP
ECO
Emergency\(hychangeover\(hyorder signal
.LP
FCM
Signalling\(hytraffic\(hyflow\(hycontrol messages
.LP
RCT
Signalling\(hyroute\(hyset\(hycongestion\(hytest signal
.LP
RSM
Signalling\(hyroute\(hyset\(hytest message
.LP
RSR
Signalling\(hyroute\(hyset\(hytest signal for restricted destination
(national option)
.LP
RST
Signalling\(hyroute\(hyset\(hytest signal for prohibited destination
.LP
TFR
Transfer\(hyrestricted signal (national option)
.LP
TFA
Transfer\(hyallowed signal
.LP
TFC
Transfer\(hycontrolled signal
.LP
TFM
Transfer\(hyprohibited\(hytransfer\(hyallowed\(hytransfer\(hyrestricted 
messages 
.LP
TFP
Transfer\(hyprohibited signal
.LP
TRA
Traffic\(hyrestart\(hyallowed signal
.LP
TRM
Traffic\(hyrestart\(hyallowed message
.LP
MIM
Management inhibit messages
.LP
LID
Link inhibit denied signal
.LP
LFU
Link forced uninhibit signal
.LP
LIN
Link inhibit signal
.LP
LIA
Link inhibit acknowledgement signal
.LP
LUA
Link uninhibit acknowledgement signal
.LP
LUN
Link uninhibit signal
.LP
LLT
Link local inhibit test signal
.LP
LRT
Link remote inhibit test signal
.LP
UFC
User part flow control messages
.LP
UPU
User part unavailable signal

.ad r
\fBNotes to Table 1/Q.704 (cont.) [2T1.704], p.\fR 
.sp 1P
.RT
.ad b
.RT
.sp 2P
.LP
\fB16\fR 	\fBState transition diagrams\fR 
.sp 1P
.RT
.sp 1P
.LP
16.1
	\fIGeneral\fR 
.sp 9p
.RT
.PP
\(sc 16 contains the description of the signalling network
functions described in \(sc\(sc\ 2 to\ 13 in the form of state transition 
diagrams 
according to the CCITT Specification and Description Language (SDL).
.PP
A set of diagrams is provided for each of the following major
functions:
.RT
.LP
	\(em
	signalling message handling (SMH), described in \(sc\ 2;
.LP
	\(em
	signalling traffic management (STM), described in \(sc\(sc\ 4
to\ 11;
.LP
	\(em
	signalling route management (SRM), described in \(sc\ 13;
.LP
	\(em
	signalling link management (SLM), described in \(sc\ 12.
.PP
16.1.1
For each major function a figure illustrates a subdivision into functional 
specification blocks, showing their functional interactions as well as 
the interactions with the other major functions. In each case this is 
followed by figures showing state transition diagrams for each of the
functional specification blocks.
.sp 9p
.RT
.PP
The detailed functional breakdown shown in the following diagrams is intended 
to illustrate a reference model and to assist interpretation of the text 
in the earlier sections. The state transition diagrams are intended to 
show precisely the behaviour of the signalling system under normal and 
abnormal conditions as viewed from a remote location. It must be emphasized 
that the 
functional partitioning shown in the following diagrams is used only to
facilitate understanding of the system behaviour and is not intended to 
specify the functional partitioning to be adopted in a practical implementation 
of the signalling system. 
.bp
.sp 2P
.LP
16.2
	\fIDrafting conventions\fR 
.sp 1P
.RT
.PP
16.2.1
Each major function is designated by its acronym (e.g. SMH =
signalling message handling).
.sp 9p
.RT
.PP
16.2.2
Each functional block is designated by an acronym which identifies it and 
also identifies the major function to which it belongs (e.g. HMRT = 
signalling message handling\(hymessage routing; TLAC = signalling traffic
management\(hylink availability control).
.PP
16.2.3
External inputs and outputs are used for interactions between
different functional blocks. Included within each input and output symbol in
the state transition diagrams are acronyms which identify the functions 
which are the source and destination of the message, e.g.: 
.LP
	L2\ \(ra | 3
	indicates that the message is sent between functional
levels:
.LP
	from:
	functional level 2,
.LP
	to:
	functional level 3.
.LP
	RTPC\ \(ra | SRC
	indicates that the message is sent within a
functional level (3 in this case):
.LP
	from:
	signalling route management\(hytransfer
prohibited control,
.LP
	to:
	signalling traffic management\(hysignalling
routing control.
.PP
16.2.4
Internal inputs and outputs are only used to indicate control of time\(hyouts. 
.sp 9p
.RT
.sp 1P
.LP
16.2.5
	\fINotations for national operations\fR 
.sp 9p
.RT
.PP
National options are included in the main body of the state
transition diagrams (STDs) with dotted or dashed lines; if their use should
exclude or modify some of the international logic, the relevant sections are
marked\ \*Qt\*U and a note is added to the figure. Also, the options are 
marked as follows: 
.RT
.LP
	Transfer restricted \(em dashed lines.
.LP
	Multiple congestion states \(em dotted lines (with the hatched
symbols removed where shown).
.sp 1P
.LP
16.3
	\fISignalling message handling\fR 
.sp 9p
.RT
.PP
Figure 23/Q.704 shows a subdivision of the signalling message
handling (SMH) function into smaller functional specification blocks and 
also shows the functional interactions between them. Each of these functional 
specification blocks is described in detail in a state transition diagram as
follows:
.RT
.LP
	a)
	message discrimination (HMDC) is shown in Figure 24/Q.704;
.LP
	b)
	message distribution (HMDT) is shown in Figure 25/Q.704;
.LP
	c)
	message routing (HMRT) is shown in Figure 26/Q.704;
.LP
	d)
	handling of messages under signalling link congestion is
shown in Figure 26a/Q.704.
.sp 1P
.LP
16.4
	\fISignalling traffic management\fR 
.sp 9p
.RT
.PP
Figure 27/Q.704 shows a subdivision of the signalling traffic
management (STM) function into smaller functional specification blocks 
and also shows functional interactions between them. Each of these functional 
specification blocks is described in detail in a state transition diagram as
follows:
.RT
.LP
	a)
	link availability control (TLAC) is shown in
Figure\ 28/Q.704;
.LP
	b)
	signalling routing control (TSRC) is shown in
Figure\ 29/Q.704;
.LP
	c)
	changeover control (TCOC) is shown in Figure\ 30/Q.704;
.LP
	d)
	changeback control (TCBC) is shown in Figure\ 31/Q.704;
.LP
	e)
	forced rerouting control (TFRC) is shown in
Figure\ 32/Q.704;
.LP
	f
)
	controlled rerouting control (TCRC) is shown in
Figure\ 33/Q.704;
.LP
	g)
	signalling traffic flow control (TSFC) is shown in
Figure\ 34a/Q.704;
.LP
	h)
	 signalling route set congestion control (TRCC) is shown in Figure\ 29a/Q.704; 
.LP
	i)
	signalling point restart control (TPRC) is shown in
Figure\ 34b/Q.704.
.bp
.sp 1P
.LP
16.5
	\fISignalling link management\fR 
.sp 9p
.RT
.PP
Figure 35/Q.704 shows a subdivision of the signalling link
management function (SLM) into smaller functional specification blocks 
and also shows functional interactions between them. Each of these functional 
specification blocks is described in detail in a state transition diagram as
follows:
.RT
.LP
	a)
	link set control (LLSC) is shown in Figure 36/Q.704;
.LP
	b)
	signalling link activity control (LSAC) is shown in
Figure\ 37/Q.704;
.LP
	c)
	signalling link activation (LSLA) is shown in
Figure\ 38/Q.704;
.LP
	d)
	signalling link restoration (LSLR) is shown in
Figure\ 39/Q.704;
.LP
	e)
	signalling link deactivation (LSLD) is shown in
Figure\ 40/Q.704;
.LP
	f
)
	signalling terminal allocation (LSTA) is shown in
Figure\ 41/Q.704;
.LP
	g)
	signalling data link allocation (LSDA) is shown in
Figure\ 42/Q.704.
.sp 1P
.LP
16.6
	\fISignalling route management\fR 
.sp 9p
.RT
.PP
Figure 43/Q.704 shows a subdivision of the signalling route
management (SRM) function into smaller functional specification blocks 
and also shows functional interactions between them. Each of these functional 
specification blocks is described in detail in a state transition diagram as
follows:
.RT
.LP
	a)
	transfer prohibited control (RTPC) is shown in
Figure\ 44/Q.704;
.LP
	b)
	transfer allowed control (RTAC) is shown in
Figure\ 45/Q.704;
.LP
	c)
	transfer restricted control (RTRC) is shown in
Figure\ 46c/Q.704;
.LP
	d)
	transfer controlled control (RTCC) is shown in
Figure\ 46a/Q.704;
.LP
	e)
	signalling route set test control (RSRT) is shown in
Figure\ 46/Q.704;
.LP
	f
)
	 signalling\(hyroute\(hyset\(hycongestion\(hytest control (RCAT) is shown 
in Figure\ 46b/Q.704. 
.sp 1P
.LP
16.7
	\fIAbbreviations used in Figures 23/Q.704 onwards\fR 
.sp 9p
.RT
.LP
	BSNT
	Backward sequence number of next signal unit to be
transmitted
.LP
	DPC
	Destination point code
.LP
	FSNC
	Forward sequence number of last message signal unit
accepted by remote level\ 2
.LP
	HMCG
	Signalling link congestion
.LP
	HMDC
	Message discrimination
.LP
	HMDT
	Message distribution
.LP
	HMRT
	Message routing
.LP
	L1
	Level 1
.LP
	L2
	Level 2
.LP
	L3
	Level 3
.LP
	L4
	Level 4
.LP
	LLSC
	Link set control
.LP
	LSAC
	Signalling link activity control
.LP
	LSDA
	Signalling data link allocation
.LP
	LSLA
	Signalling link activation
.LP
	LSLD
	Signalling link deactivation
.LP
	LSLR
	Signalling link restoration
.LP
	LSTA
	Signalling terminal allocation
.LP
	MGMT
	Management system
.LP
	RCAT
	Signalling\(hyroute\(hyset\(hycongestion\(hytest control
.LP
	RSRT
	Signalling route set test control
.bp
.LP
	RTAC
	Transfer allowed control
.LP
	RTCC
	Transfer controlled control
.LP
	RTPC
	Transfer prohibited control
.LP
	RTRC
	Transfer restricted control
.LP
	SLM
	Signalling link management
.LP
	SLS
	Signalling link selection
.LP
	SLTC
	Signalling link test control
.LP
	SMH
	Signalling message handling
.LP
	SRM
	Signalling route management
.LP
	STM
	Signalling traffic management
.LP
	TCBC
	Changeback control
.LP
	TCOC
	Changeover control
.LP
	TCRC
	Controlled rerouting control
.LP
	TFRC
	Forced rerouting control
.LP
	TLAC
	Link availability control
.LP
	TPRC
	Signalling point restart control
.LP
	TRCC
	Signalling route set congestion control
.LP
	TSFC
	Signalling traffic flow control
.LP
	TSRC
	Signalling routing control
.sp 1P
.LP
16.8
	\fITimers and timer values\fR 
.sp 9p
.RT
.PP
The following timers have been defined. The ranges are given below. The 
values, in brackets, are the minimum values for use when routes with long 
propagation delays are used (e.g.,\ routes including satellite 
sections).
.RT
.LP
	T1
	Delay to avoid message mis\(hysequencing on changeover.
.LP
500\ (800)\ to 1200\ ms.
.LP
	T2
	Waiting for changeover acknowledgement.
.LP
700\ (1400)\ to 2000\ ms.
.LP
	T3
	Time controlled diversion\(hydelay to avoid mis\(hysequencing
on changeback.
.LP
500\ (800)\ to 1200\ ms.
.LP
	T4
	Waiting for changeback acknowledgement (first attempt).
.LP
500\ (800)\ to 1200\ ms.
.LP
	T5
	Waiting for changeback acknowledgement (second attempt).
.LP
500\ (800)\ to 1200\ ms.
.LP
	T6
	Delay to avoid message mis\(hysequencing on controlled
rerouting.
.LP
500\ (800)\ to 1200\ ms.
.LP
	T7
	Waiting for signalling data link connection
acknowledgement.
.LP
1\ to 2\ seconds.
.LP
	T8
	Transfer prohibited inhibition timer (transient solution).
.LP
800\ to 1200\ ms.
.LP
	T9
	Not used.
.LP
	T10
	Waiting to repeat signalling route set test message.
.LP
30\ to 60\ seconds.
.bp
.LP
	T11
	Transfer restricted timer. (This is one way of
implementing the function described in \(sc\ 13.4 and
mainly intended to simplify STPs.)
.LP
30\ to 90\ seconds.
.LP
	T12
	Waiting for uninhibit acknowledgement.
.LP
800\ to 1500\ ms.
.LP
	T13
	Waiting for force uninhibit.
.LP
800\ to 1500\ ms.
.LP
	T14
	Waiting for inhibition acknowledgement.
.LP
2\ to 3\ seconds.
.LP
	T15
	Waiting to start signalling route set congestion test.
.LP
2\ to 3\ seconds.
.LP
	T16
	Waiting for route set congestion status update.
.LP
1.4\ to 2\ seconds.
.LP
	T17
	Delay to avoid oscillation of initial alignment failure
and link restart.
.LP
800\ to 1500\ ms.
.LP
	T18
	Timer at restarting STP, waiting for signalling links to
become available.
.LP
20 seconds (provisional value).
.LP
	T19
	Timer at restarting STP, started after T18, waiting to
receive all traffic restart allowed messages.
.LP
4 seconds (provisional value).
.LP
	T20
	Timer at restarting STP, started after T19, waiting to
broadcast traffic restart allowed messages, and restart
remaining traffic.
.LP
4 seconds (provisional value).
.LP
	T21
	Timer at restarting signalling point having no STP
function, waiting to restart traffic routed through
adjacent\ SP;
.LP
AND timer at STP adjacent to restarting STP, waiting for
traffic restart allowed message;
.LP
AND timer at SP having no STP function adjacent to restarting
SP, waiting to restart any traffic to route through
adjacent\ SP.
.LP
30\ seconds (provisional value).
.LP
	T22
	Local inhibit test timer.
.LP
3 min to 6\ min (provisional value).
.LP
	T23
	Remote inhibit test timer.
.LP
3 min to 6 min (provisional value).
.LP
	T24
	Stabilising timer after removal of local processor outage,
used in LPO latching to RPO (national option).
.LP
500 ms (provisional value).
.LP
.rs
.sp 14P
.ad r
Blanc
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 23/Q.704, p.18\fR 
.sp 1P
.RT
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.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 24/Q.704, p.19\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 25/Q.704 (feuillet 1 sur 2), p.20\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 25/Q.704 (feuillet 2 sur 2), p.21\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 26/Q.704 (feuillet 1 sur 2), p.22\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 26/Q.704 (feuillet 2 sur 2), p.23\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
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\fBFigure 26a/Q.704, p.24\fR 
.sp 1P
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.LP
.bp
.LP
.rs
.sp 47P
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\fBFigure 27/Q.704 (feuillet 1 sur 3), p.25\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 27/Q.704 (feuillet 2 sur 3), p.26\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 27/Q.704 (feuillet 3 sur 3), p.27\fR 
.sp 1P
.RT
.ad b
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.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 1 sur 17), p.28\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 2 sur 17), p.29\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 3 sur 17), p.30\fR 
.sp 1P
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.ad b
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.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 3bis sur 17), p.31\fR 
.sp 1P
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.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 4 sur 17), p.32\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 5 sur 17), p.33\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 5bis sur 17), p.34\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 6 sur 17), p.35\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 6bis sur 17), p.36\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 7 sur 17), p.37\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 8 sur 17), p.38\fR 
.sp 1P
.RT
.ad b
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.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 9 sur 17), p.39\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 10 sur 17), p.40\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 11 sur 17), p.41\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 12 sur 17), p.42\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 13 sur 17), p.43\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 14 sur 17), p.44\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 15 sur 17), p.45\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 16 sur 17), p.46\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 28/Q.704 (feuillet 17 sur 17), p.47\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp