npi.7.man

This a separate release of the OpenSS7 X/Open XTI/TLI library, TLI modules (timod, tirdwr) and the I

:_:_
:Reset:T{
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.hy 0
\fBN_RESET_REQ\fR(7),
\fBN_RESET_IND\fR(7),
\fBN_RESET_RES\fR(7),
\fBN_RESET_CON\fR(7)
T}
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T{
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Connection
Release
T}:T{
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Connection
Release
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\fBN_DISCON_REQ\fR(7),
\fBN_DISCON_IND\fR(7),
\fBN_OK_ACK\fR(7),
\fBN_ERROR_ACK\fR(7)
T}
.TE
.PP
.sp
.ce 1
.B TABLE 2.  Service Primitives for Connectionless Mode Data Transfer
.TS
tab(:) box center;
lb|lb|lbw(2.2i)s
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STATE:SERVICE:PRIMITIVES
_
T{
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.hy 0
Local
Management
T}:T{
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Information
Reporting
T}:T{
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\fBN_INFO_REQ\fR(7),
\fBN_INFO_ACK\fR(7),
\fBN_ERROR_ACK\fR(7)
T}
:_:_
:Bind:T{
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.hy 0
\fBN_BIND_REQ\fR(7),
\fBN_BIND_ACK\fR(7),
\fBN_UNBIND_REQ\fR(7),
\fBN_OK_ACK\fR(7),
\fBN_ERROR_ACK\fR(7)
T}
:_:_
:T{
.ad l
.hy 0
Options
Management
T}:T{
.ad l
.hy 0
\fBN_OPTMGMT_REQ\fR(7),
\fBN_OK_ACK\fR(7),
\fBN_ERROR_ACK\fR(7)
T}
_
T{
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.hy 0
Connectionless
Mode Data Transfer
T}:T{
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.hy 0
Data
Transfer
T}:T{
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\fBN_UNITDATA_REQ\fR(7),
\fBN_UNITDATA_IND\fR(7),
\fBN_UDERROR_IND\fR(7)
T}
.TE
.SH "NPI Services Definition"
This section describes the services of the NPI primitives.  Time-sequence
diagrams that illustrate the sequence of primitives are included.  (Conventions
for the time-sequence diagrams are defined in CCITT X.210 [8].) The format of
the primitives will be defined later in this document.
.SS "Local Management Services Definition"
The services defined in this section are outside the scope of the
international standards.  These services apply to both connection-mode as well
as the connection-less modes of communication.  They are invoked for the
initialization/de-initialization of a stream connected to the NS provider.  They
are also used to manage options supported by the NS provider and to report
information on the supported parameter values.
.PP
.B Network Information Reporting Service.
This service provides information on the options supported by the NS provider.
.IP \(em \w'\(em\(em'u
.BR N_INFO_REQ (7):
This primitive requests that the NS provider return the values of all the
supported protocol parameters.  This request may be invoked during any phase.
.IP \(em \w'\(em\(em'u
.BR N_INFO_ACK (7):
This primitive is in response to the
.BR N_INFO_REQ (7)
primitive and returns the
values of the supported protocol parameters to the NS user.
.PP
.B NS User Bind Service.
This service allows a network address to be associated with a stream.  It
allows the NS user to negotiate the number of connect indications that can
remain unacknowledged for that NS user (a connect indication is considered
unacknowledged while it is awaiting a corresponding connect response or
disconnect request from the NS user).  This service also defines a mechanism
that allows a stream (bound to a network address of the NS user) to be reserved
to handle incoming calls only.  This stream is referred to as the listener
stream.
.IP \(em \w'\(em\(em'u
.BR N_BIND_REQ (7):
This primitive requests that the NS user be bound to a particular network
address, and negotiate the number of allowable outstanding connect indications
for that address.
.IP \(em \w'\(em\(em'u
.BR N_BIND_ACK (7):
This primitive is in response to the
.BR N_BIND_REQ (7)
primitive and indicates to the
user that the specified NS user has been bound to a network address.
.PP
.B NS User Unbind Service.
This service allows the NS user to be unbound from a network address.
.IP \(em \w'\(em\(em'u
.BR N_UNBIND_REQ (7):
This primitive requests that the NS user be unbound from
* the network address that it had previously been bound to.
.PP
.B Receipt Acknowledgment Service.
.IP \(em \w'\(em\(em'u
.BR N_OK_ACK (7):
This primitive indicates to the NS user that the previous NS
user originated primitive was received successfully by the NS provider.
.PP
.B Options Management Service.
This service allows the NS user to manage the QOS parameter values associated
with the NS provider.
.IP \(em \w'\(em\(em'u
.BR N_OPTMGMT_REQ (7):
This primitive allows the NS user to select default values for QOS parameters
within the range supported by the NS provider, and to indicate the default
selection of receipt confirmation.
.PP
.B Error Acknowledgment Service.
.IP \(em \w'\(em\(em'u
.BR N_ERROR_ACK (7):
This primitive indicates to the NS user that a non-fatal error has occurred in
the last NS user originated request or response primitive on the stream.
.SS "Connection-Mode Network Services Definition"
This section describes the required network service primitives that define the
CONS interface.
.PP
The queue model for CONS is discussed in more detail in CCITT X.213 section
9.2.  The queue model represents the operation of a network connection in the
abstract by a pair of queues linking the two network addresses.  There is one
queue for each direction of information flow.
.PP
Each queue represents a flow control function in one direction of transfer.
The ability of a user to add objects to a queue will be determined by the
behavior of the user removing objects from that queue, and the state of the
queue.  The pair of queues is considered to be available for each potential NC.
Objects that are entered or removed from the queue are either as a result of
interactions at the two network addresses, or as the result of NS provider
initiatives.
.IP \(em \w'\(em\(em'u
A queue is empty until a connect object has been entered and can be returned
to this state, with loss of its contents, by the NS provider.
.IP \(em \w'\(em\(em'u
Objects may be entered into a queue as a result of the actions of the source
NS user,subject to control by the NS provider;
.IP \(em \w'\(em\(em'u
Objects may also be entered into a queue by the NS provider.
.IP \(em \w'\(em\(em'u
Objects are removed from the queue under the control of the receiving NS
user.
.IP \(em \w'\(em\(em'u
Objects are normally removed under the control of the NS user in the same
order as they were entered except:
.IP \(em \w'\(em\(em'u
if the object is of a type defined to be able to advance ahead of the
preceding object (however, no object is defined to be able to advance ahead of
another object of the same type), or
.IP \(em \w'\(em\(em'u
if the following object is defined to be destructive with respect to the
preceding object on the queue.
.PP
If necessary, the last object on the queue will be deleted to allow a
destructive object to be entered - they will therefore always be added
to the queue.  For example, "disconnect" objects are defined to be destructive
with respect to all other objects.  "Reset" objects are defined to be
destructive with respect to all other objects except "connect", "disconnect",
and other "reset" objects.  Table 3 shows the ordering relationships among the
queue model objects.

.\"Object X CONNECT NORMAL EXP.  DATA RESET DISCObject Y DATA NSDU ACK CONNECT N/A
.\"- - - - DES NORMAL DATA N/A - AA AA DES DES EXP.  NSDU N/A - - AA DES DES DATA
.\"ACK N/A - AA - DES DES RESET N/A - - - - DES DISC N/A N/A N/A N/A N/A AA
.\"Indicates that Object X is defined to be able to advance ahead of
.\"precedingObject Y.

.\"DES Indicates that Object X is defined to be destructive with respect to the
.\"precedingObject Y.  - Indicates that Object X is neither destructive with
.\"respect to Object Y, nor able toadvance ahead of Object Y.  N/A Indicates that
.\"Object X will not occur in a position succeeding Object Y in a validstate of a
.\"queue.

.\"TABLE 3.  Ordering Relationships Between Queue Model Objects
.PP
.B Connection Establishment Phase
A pair of queues is associated with an NC between two network addresses when
the NS provider receives an
.BR N_CONN_REQ (7)
primitive at one of the network
addresses resulting in a connect object being entered into the queue.  The
queues will remain associated with the NC until a
.BR N_DISCON_REQ (7)
primitive
(resulting in a disconnect object) is either entered or removed from a queue.
Similarly, in the queue from the called NS user, objects can be entered into
the queue only after the connect object associated with the
.BR N_CONN_RES (7)
has
been entered into the queue.  Alternatively, the called NS user can enter a
disconnect object into the queue instead of the connect object to terminate
the NC.  The NC establishment procedure will fail if the NS provider is unable
to establish an NC,or if the destination NS user is unable to accept the
.BR N_CONN_IND (7)
(see NC Release primitive definition).
.PP
.B User Primitives for Successful Network Connection Establishment
.IP \(em \w'\(em\(em'u
.BR N_CONN_REQ (7):
This primitive requests that the NS provider make a connection
to the specified destination.
.IP \(em \w'\(em\(em'u
.BR N_CONN_RES (7):
This primitive requests that the NS provider accept a previous connection
indication.
.PP
.B Provider Primitives for Successful Network Connection Establishment
.IP \(em \w'\(em\(em'u
.BR N_CONN_IND (7):
This primitive indicates to the NS user that a connect request
has been made by a user at the specified source address.
.IP \(em \w'\(em\(em'u
.BR N_CONN_CON (7):
This primitive indicates to the NS user that a connect request
has been confirmed on the specified responding address.
.PP
.B Data Transfer Phase
Flow control on the NC is done by management of the queue capacity, and by
allowing objects of certain types to be inserted to the queues, as shown in
Table 4.
.\"
.\"OBJECT X OCTETS OF NORMAL EXPEDITED DATAOBJECT Y DATA/ DATA ACKNOWLEDGEMENT
.\"Octets of NormalData Yes Yes No Expedited Data No Yes No DataAcknowledgement
.\"No No No
.\"
.\"Yes The addition of Object X may prevent further addition of Object Y.  No The
.\"addition of Object X may not prevent the addition of Object Y.
.\"
.\"TABLE 4.  Flow Control Relationships Between Queue Model Objects
.PP
.B User Primitives for Data Transfer
.IP \(em \w'\(em\(em'u
.BR N_DATA_REQ (7):
This primitive requests that the NS provider transfer the
specified data.
.IP \(em \w'\(em\(em'u
.BR N_DATACK_REQ (7):
This primitive requests that the NS provider acknowledge
the data that had previously been received with receipt confirmation
requested.
.IP \(em \w'\(em\(em'u
.BR N_EXDATA_REQ (7):
This primitive requests that the NS provider transfer
the specified expedited network service data unit.
.PP
.B Provider Primitives for Data Transfer
.IP \(em \w'\(em\(em'u
.BR N_DATA_IND (7):
This primitive indicates to the NS user that this message
contains data.
.IP \(em \w'\(em\(em'u
.BR N_DATACK_IND (7):
This primitive indicates to the NS user that the remote NS
user has acknowledged the data that had previously been sent with receipt
confirmation requested.
.IP \(em \w'\(em\(em'u
.BR N_EXDATA_IND (7):
This primitive indicates to the NS user that this message
unit contains expedited data.
.PP
The sequence of primitives may remain incomplete if a
.B N_RESET
or
.B N_DISCON
primitive occurs.
.PP
A NS user must not issue an
.BR N_DATACK_REQ (7)
primitive if no
.BR N_DATA_IND (7)
with
confirmation request set has been received, or if all such
.BR N_DATA_IND (7)
have
been previously acknowledged.  Following a reset procedure
.RB ( N_RESET_REQ (7)
or
.BR N_RESET_IND (7)),
a NS user may not issue aN_DATACK_REQ to acknowledge an
outstanding
.BR N_DATA_IND (7)
received before the reset procedure was signaled.  (Note
-- The withholding of confirmation of receipt by a NS user can have an effect
on the attainable throughput on the NC.)
.PP
.B Reset Operation Primitives
The reset service is used by the NS user to resynchronize the use of the NC,
or by the NS provider to report detected loss of unrecoverable data.
.PP
The reset procedure involves the following interactions: