The \fIdial\(hyout\(hyby\(hythe\(hyPSPDN availability\fR attribute allows
the use of dial\(hyout\(hyby\(hythe\(hyPSPDN operation.
.RT
.sp 1P
.LP
3.1.8.1
\fINetwork default\fR
.sp 9p
.RT
.PP
When the \fIdial\(hyout\(hyby\(hythe\(hyPSPDN availability\fR is specified as
network default, the network chooses whether or not to offer
dial\(hyout\(hyby\(hythe\(hyPSPDN operation. When dial\(hyout\(hyby\(hythe\(hyPSPDN
operation is
offered, the PSPDN attempts to establish a switched access path to the PSN
number given in a \fIcall request\fR packet.
.RT
.sp 1P
.LP
3.1.8.2
\fIUser selectable\fR
.sp 9p
.RT
.PP
When the \fIdial\(hyout\(hyby\(hythe\(hyPSPDN availability\fR is specified
as user selectable, the capability to have dial\(hyout\(hyby\(hythe\(hyPSPDN
availability operation with a particular DTE is chosen by the user. When
the \fIdial\(hyout\(hyby\(hythe\(hyPSPDN\fR \fIavailability\fR is selected,
the \fIregistered PSN number\fR attribute must also be selected. Then the
network dials out to the DTE whenever the \fIregistered\fR
\fIaddress\fR is used in a \fIcall request\fR packet and there is not already a
switched access path.
.RT
.sp 1P
.LP
3.1.9
\fIDial\(hyout access type\fR
.sp 9p
.RT
.PP
The \fIdial\(hyout access type\fR attribute applies to
dial\(hyout\(hyby\(hythe\(hyPSPDN operation and allows a DTE to choose modem
characteristics or a user class of service or characteristics of an ISDN
connection, possibly other than the national default, from those offered
by the network. \fIDial\(hyout access type\fR refers to the modem characteristics
(in the
case of the PSTN) or the X.1 user class (in the case of the CSPDN) or the
characteristics of an ISDN connection (in the case of ISDN) that are used
for switched access line operation at the physical layer, see \(sc\ 4.
A national
default dial\(hyout access type is made by the PSPDN for each PSN through which
access is permitted.
.PP
Note that for dial\(hyin\(hyby\(hythe\(hyDTE through the PSTN, the modem
characteristics of the PSPDN port dialled into are used. For dial\(hyin\(hyby\(hythe\(hyDTE
through the CSPDN, the X.1 user class of the PSPDN port called is
used.
.bp
.PP
\fINote\ 1\fR \ \(em\ Some networks may use the procedures of
Recommendation\ V.100 to perform modem selection.
.PP
\fINote\ 2\fR \ \(em\ The modem used determines whether the transmission
facility is full or half duplex. Therefore, there is no attribute for the
type of
transmission facility operation.
.RT
.sp 1P
.LP
3.1.9.1
\fINetwork default\fR
.sp 9p
.RT
.PP
When the \fIdial\(hyout access type\fR is specified as network default,
the national default modem characteristics are used for dial\(hyout\(hyby\(hythe\(hyPSPDN
through the PSTN. For dial\(hyout\(hyby\(hythe\(hyPSPDN through the CSPDN,
the national
default X.1 user class is used. For dial\(hyout\(hyby\(hythe\(hyPSPDN through
an ISDN, the national default for rate adaption method is used, see Recommendation\
X.31 for the applicable method.
.RT
.sp 1P
.LP
3.1.9.2
\fIUser selectable\fR
.sp 9p
.RT
.PP
When the \fIdial\(hyout access type\fR is specified as user selectable,
the modem characteristics selected for this \fIDTE identity\fR , from those
offered by the network, are used for dial\(hyout\(hyby\(hythe\(hyPSPDN
through the PSTN. For
dial\(hyout\(hyby\(hythe\(hyPSPDN through the CSPDN, the X.1 user class,
selected for this \fIDTE identity\fR from those offered by the network,
is used. For
dial\(hyout\(hyby\(hythe\(hyPSPDN through an ISDN, the X.1 user class,
selected for this
\fIDTE identity\fR from those offered by the network, is used.
.RT
.sp 1P
.LP
3.1.10
\fIX.32 optional user facilities\fR
.sp 9p
.RT
.PP
Two X.32 optional user facilities, \fItemporary location\fR and
\fIsecure dial\(hyback\fR are included within this attribute. Both of these
optional user facilities are defined in \(sc\ 7.2. It is optional for the
PSPDN to offer
these facilities.
.RT
.sp 1P
.LP
3.1.11
\fIDCE identity presentation\fR
.sp 9p
.RT
.PP
The PSPDN chooses whether or not to offer DCE identity
presentation. When DCE identity presentation is offered, the \fIDCE identity\fR
\fIpresentation\fR attribute defines the DCE identification method used by the
PSPDN. The PSPDN may choose to use a DCE identification method for both
dial\(hyin\(hyby\(hythe\(hyDTE operation and dial\(hyout\(hyby\(hythe\(hyPSPDN
operation or for only
dial\(hyout\(hyby\(hythe\(hyDTE operation. When the DCE identification
is done for both
operations, the method is the same for dial\(hyin\(hyby\(hythe\(hyDTE operation
and
dial\(hyout\(hyby\(hythe\(hyPSPDN operation. The PSPDN selects one of the DCE
identification methods given in \(sc\ 2.5.
.PP
Some networks may include a DTE profile designator as part of the DCE identity
in order to inform the DTE of the \fIDTE profile\fR applicable to the
DTE/DCE interface during this instance of switched access. The DTE profile
designator is a string of octets that may be assigned by the PSPDN to the
\fIDTE\ identity\fR as a name for the specific \fIDTE profile\fR .
.RT
.sp 1P
.LP
3.1.12
\fILink layer address assignment\fR
.sp 9p
.RT
.PP
The \fIlink layer address assignment\fR attribute defines the mechanism
used to determine the link layer addresses.
.PP
\fINote\fR \ \(em\ Other methods of link layer address assignment than those
described below are for further study.
.RT
.sp 1P
.LP
3.1.12.1
\fINetwork default\fR
.sp 9p
.RT
.PP
When the \fIlink layer address assignment\fR is specified as network
default, the link level addresses are assigned depending on the direction of
the switched access call as defined in \(sc\ 5.2 (same as Recommendation\
T.70).
.PP
Alternatively, \fIlink layer address assignment\fR that is dependent on
the roles of the equipment as DTE and DCE, as defined in \(sc\ 5.2 (same
as \(sc\ 2.4.2 of Recommendation\ X.25), may be provided by some networks.
.PP
\fINote\ 1\fR \ \(em\ The dial\(hyout\(hyby\(hythe\(hyPSPDN operation will
only operate
properly when the DTE and the PSPDN implement the same \fIlink layer address\fR
\fIassignment\fR method.
.PP
\fINote\ 2\fR \ \(em\ Assigning the link layer addresses according to the
roles of the equipment as DTE and DCE does not allow for two DTEs to interoperate
directly without an intervening PSPDN.
.bp
.RT
.sp 1P
.LP
3.1.12.2
\fIUser selectable\fR
.sp 9p
.RT
.PP
When the \fIlink layer address assignment\fR is specified as user
selectable, the user designates whether the link level addresses are assigned
depending on the direction of the switched access call or depending on
the
roles of the equipment as DTE and DCE (see \(sc\ 5.2).
.RT
.sp 1P
.LP
3.2
\fISummary of DTE services\fR
.sp 9p
.RT
.PP
The type of each attribute is given for the three DTE services in Table\
2/X.32.
.RT
.LP
.sp 2
.ce
\fBH.T. [T2.32]\fR
.ce
TABLE\ 2/X.32
.ce
\fBSummary of DTE services\fR
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
rw(66p) | lw(54p) | lw(54p) | lw(54p) .
Services
.T&
rw(66p) | cw(54p) | cw(54p) | cw(54p) .
Nonidentified Identified Customized
.T&
lw(66p) | cw(54p) | cw(54p) | cw(54p) .
Attributes
_
.T&
lw(66p) | cw(54p) | cw(54p) | cw(54p) .
DTE identity \(em\(em\(em Yes Yes
_
.T&
lw(66p) | cw(54p) | cw(54p) | lw(54p) .
DTE identification method \(em\(em\(em Any (ND) T{
Prior to virtual circuit
establishment\ (ND)
T}
_
.T&
lw(66p) | cw(54p) | cw(54p) | cw(54p) .
DTE address \(em\(em\(em Note\ 4 Yes
_
.T&
lw(66p) | cw(54p) | cw(54p) | cw(54p) .
Registered address \(em\(em\(em Note\ 1 Yes
_
.T&
lw(66p) | cw(54p) | cw(54p) | cw(54p) .
Registered PSN number \(em\(em\(em \(em\(em\(em User selectable
_
.T&
lw(66p) | cw(54p) | cw(54p) | cw(54p) .
X.25 subscription set ND Note\ 2 User selectable
_
.T&
lw(66p) | cw(54p) | cw(54p) | cw(54p) .
Logical channel assignment ND ND User selectable
_
.T&
lw(66p) | cw(54p) | cw(54p) | cw(54p) .
T{
Dial\(hyout\(hyby\(hythe\(hyPSPDN availability
T} ND Note\ 1 User selectable
_
.T&
lw(66p) | cw(54p) | cw(54p) | cw(54p) .
Dial\(hyout access type ND ND User selectable
_
.T&
lw(66p) | cw(54p) | cw(54p) | cw(54p) .
X.32 optional user facilities \(em\(em\(em \(em\(em\(em User selectable
_
.T&
lw(66p) | cw(54p) | cw(54p) | cw(54p) .
DCE identity presentation ND ND ND
_
.T&
lw(66p) | cw(54p) | cw(54p) | cw(54p) .
Link layer address assignment ND ND T{
User selection
Note\ 3
\(em\(em\(em
not provided
ND
network default
Yes
provided
.parag
\fINote\ 1\fR
\ \(em\ In this DTE service, the use of \fIregistered addresses\fR
for some DTEs is a network option. When the DTE is assigned a \fIregistered address\fR
, the value of the \fIdial\(hyout\(hyby\(hythe\(hyPSPDN availability\fR
attribute is user selectable.
Otherwise, (if no \fIregistered address\fR
is assigned to the DTE), the
availability of dial\(hyout\(hyby\(hythe\(hyPSPDN operation is by network default.
.parag
\fINote\ 2\fR
\ \(em\ ND or, if \fINUI override\fR
is in effect, user selectable packet layer facility values (Annex H/X.25).
.parag
\fINote\ 3\fR
\ \(em\ In the case of dial\(hyin\(hyby\(hythe\(hyDTE operation, the link layer address values assigned are the same for both assignment methods and, therefore, the
values are not dependent on the assignment method selected by the user.
.parag
\fINote\ 4\fR
\ \(em\ In this DTE service, the use of \fIDTE addresses\fR
for some DTEs is a network option.
.parag
T}
_
.TE
.nr PS 9
.RT
.ad r
\fBTableau 2/X.32 [T2.32], p. 5\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.sp 1P
.LP
3.3
\fINonidentified DTE service\fR
.sp 9p
.RT
.PP
The values of the attributes for the \fInonidentified\fR DTE service
defined in \(sc\ 2.3.2.1 are shown in the \*Qnonidentified\*U column of
Table\ 2/X.32:
.RT
.LP
\(em
no \fIDTE identity\fR is established;
.LP
\(em
no \fIDTE identification\fR method is used.
.PP
Generally, no optional user facilities are available except those governing
the direction of virtual call placement (i.e.\ incoming calls barred, outgoing
calls barred, one\(hyway logical channel outgoing, and one\(hyway logical
channel incoming) and those that can be used on a per\(hyvirtual\(hycall basis
without prior subscription. In addition, some networks may allow the use
of:
.LP
a)
some subscription\(hytime optional user facilities without
prior subscription. (The network may make these known by
publication or through the use of the \fIon\(hyline facility\fR \fIregistration\fR
facility; in such cases, a PSPDN should consider
making its identity known nonidentified DTEs), and
.LP
b)
some subscription\(hytime optional user facilities that must be
requested by the DTE through the use of the \fIon\(hyline facility\fR
\fIregistration\fR facility.
.PP
The X.25 link layer options and system parameters and the X.25
subscription\(hytime optional user facilities are categorized for
dial\(hyin\(hyby\(hythe\(hyDTE and dial\(hyout\(hyby\(hythe\(hyPSPDN operation
in Table\ 3/X.32
as:
.LP
\(em
an \*QAVAIL\(hyNS\*U link layer system parameter, which is set by
the network on all networks offering \fInonidentified\fR DTE
service;
.LP
\(em
an \*QAVAIL\(hyBAS\*U optional user facility or link layer option,
which is available on all networks offering \fInonidentified\fR DTE
service. This facility is in effect even if not requested;
.LP
\(em
an \*QAVAIL\(hyOPT\*U optional user facility, which is available on
some networks offering the \fInonidentified\fR DTE service and the
availability of which is made known through either publication
or use of the \fIon\(hyline facility registration\fR facility. These
facilities can be used without further request when operating on
these networks;
.LP
\(em
an \*QAVAIL\(hyRQ\*U optional user facility, which is available on
some networks offering the \fInonidentified\fR DTE service and the
use of which must be requested through the \fIon\(hyline facility\fR
\fIregistration\fR facility; or
.LP
\(em
a \*QNO\*U optional user facility or line level option, which is
not available on any network offering \fInonidentified\fR DTE
service.
.PP
The DTE may use any per\(hycall X.25 facility that is supported by
the PSPDN and that does not require prior subscription.
.sp 1P
.LP
3.4
\fIIdentified DTE service\fR
.sp 9p
.RT
.PP
The values of the attributes for the \fIidentified\fR DTE service
(defined in \(sc\ 2.3.2.2) are shown in the \*Qidentified\*U column of
Table\ 2/X.32.
.RT
.LP
\(em
A \fIDTE identity\fR that has been agreed to explicitly or
implicitly is provided to the nework.
.LP
\(em
The \fIX.25 subscription\fR set is the same as in the
\fInonidentified\fR DTE service except that:
.LP
a)
for dial\(hyin\(hyby\(hythe\(hyDTE operation, in which the \fINUI\fR
\fIoverride\fR facility is in effect at the DTE/DCE interface,
the \fINUI selection\fR facility, as defined in
Recommendation\ X.25, can be used to invoke user selected
packet layer facility values (see \(sc\ 6.3 and Annex\ H/X.25),
and
.LP
b)
the \fIlocal charging prevention\fR facility is not in
effect.
.PP
The DTE may use any per\(hycall X.25 facility which is supported by the
PSPDN and which does not require prior subscription.
.bp
.ce
\fBH.T. [1T3.32]\fR
.ce
TABLE\ 3/X.32
.ce
\fBAvailability of link level options and system parameters and packet\fR
.ce
.ce
\fBlevel subscription\(hytime facilities in the nonidentified DTE service\fR