npi.7

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.IP \(em 4
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 4
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 4
Objects may also be entered into a queue by the NS provider.
.IP \(em 4
Objects are removed from the queue under the control of the receiving NS
user.
.IP \(em 4
Objects are normally removed under the control of the NS user in the same
order as they were entered except:
.IP \(em 4
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 4
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 4
.BR N_CONN_REQ (7):
This primitive requests that the NS provider make a connection
to the specified destination.
.IP \(em 4
.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 4
.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 4
.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 4
.BR N_DATA_REQ (7):
This primitive requests that the NS provider transfer the
specified data.
.IP \(em 4
.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 4
.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 4
.BR N_DATA_IND (7):
This primitive indicates to the NS user that this message
contains data.
.IP \(em 4
.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 4
.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:
.IP A. 4
a
.BR N_RESET_REQ (7)
from the NS user, followed by a
.BR N_RESET_CON (7)
from the NS provider;
or
.IP B. 4
a
.BR N_RESET_IND (7)
from the NS provider, followed by a
.BR N_RESET_RES (7)
from the NS user.
.PP
The complete sequence of primitives depends upon the origin/s of the reset
action.  The reset service may be:
.IP 1. 4
invoked by one NS user, leading to interaction (A) with that NS user
and interaction (B) with the peer NS user;
.IP 2. 4
invoked by both NS users, leading to interaction (A) with both NS users;
.IP 3. 4
invoked by the NS provider, leading to interaction (B) with both NS users;
.IP 4. 4
invoked by one NS user and the NS provider, leading to interaction (A) with
the originating NS user and (B) with the peer NS user.
.PP
The
.BR N_RESET_REQ (7)
acts as a synchronization mark in the flow of
.BR N_DATA ,
.BR N_EXDATA ,
and
.B N_DATACK
primitives transmitted by the issuing NS user; the
.BR N_RESET_IND (7)
acts as a synchronization mark in the flow of
.BR N_DATA ,
.BR N_EXDATA ,
and
.B N_DATACK
primitives received by the receiving NS user.  Similarly,
.BR N_RESET_RES (7)
acts as a
synchronization mark in the flow of
.BR N_DATA ,
.BR N_EXDATA ,
and
.B N_DATACK
primitives
transmitted by the responding NS user, while the
.BR N_RESET_CON (7)
acts as a
synchronization mark in the flow of
.BR N_DATA ,
.BR N_EXDATA ,
and
.B N_DATACK
primitives
received by the NS user that originally issued the reset.  The resynchronizing
properties of the reset service are the following:
.IP i. 4
All
.BR N_DATA ,
.BR N_EXDATA ,
and
.B N_DATACK
primitives issued before issuing
the
.BR N_RESET_REQ (7)/ N_RESET_RES (7)
that have not been delivered to the other NS user
before the
.BR N_RESET_IND (7)/ N_RESET_CON (7)
are issued by the NS provider,should be
discarded by the NS provider.
.IP ii. 4
Any
.BR N_DATA ,
.BR N_EXDATA ,
and
.B N_DATACK
primitives issued after the synchronization
mark will not be delivered to the other NS user before the synchronization
mark is received.
.PP
.B User Primitives for Reset Operations
.IP \(em 4
.BR N_RESET_REQ (7):
This primitive requests that the NS provider reset the
network connection.
.IP \(em 4
.BR N_RESET_RES (7):
This primitive indicates to the NS provider that the NS user
has accepted a reset indication.
.PP
.B Provider Primitives for Reset Operations
.IP \(em 4
.BR N_RESET_IND (7):
This primitive indicates to the NS user that the
network connection has been reset.
.IP \(em 4
.BR N_RESET_CON (7):
This primitive indicates to the NS user that the reset request
has been confirmed.
.PP
The sequence of primitives may remain incomplete if a
.B N_DISCON
primitive occurs.
.PP
.B Connection Termination Phase
The NC release procedure is initialized by the insertion of a disconnect
object(associated with a
.BR N_DISCON_REQ) (7)
into the queue.  As shown in Table 3, the disconnect procedure is destructive
with respect to other objects in the queue, and eventually results in the
emptying of queues and termination of the NC connection.
.PP
The sequence of primitives depends on the origin of the release action.  The
sequence may be:
.IP 1. 4
invoked by one NS user, with a request from that NS user leading to an
indication to the other;
.IP 2. 4
invoked by both NS users, with a request from each of the NS users;
.IP 3. 4
invoked by the NS provider, with an indication to each of the NS users;
.IP 4. 4
invoked independently by one NS user and the NS provider, with a request
from the originating NS user and an indication to the other.
.PP
.B User Primitives for Connection Termination
.IP \(em 4
.BR N_DISCON_REQ (7):
This primitive requests that the NS provider deny
an outstanding request for a connection or disconnect an existing connection.
.PP
.B Provider Primitives for Connection Termination
.IP \(em 4
.BR N_DISCON_IND (7):
This primitive indicates to the NS user that either a request
for connection has been denied or an existing connection has been terminated.
.PP
A NS user may reject an NC establishment attempt by issuing a
.BR N_DISCON_REQ (7).
The originator parameter in the
.B N_DISCON
primitives will indicate NS user invoked release.
.PP
If the NS provider is unable to establish an NC, it indicates this to the
requester by an
.BR N_DISCON_IND (7).
The originator in this primitive indicates an NS provider invoked release.
.SS "Connectionless Network Services Definition"
The CLNS allows for the transfer of the NS user data in one or both
directions simultaneously without establishing a network connection.  A set of
primitives are defined that carry user data and control information between
the NS user and NS provider entities.  The primitives are modeled as requests
initiated by the NS user and indications initiated by the NS provider.
Indications may be initiated by the NS provider independently from requests by
the NS user.
.PP
The connectionless network service consists of one phase.
.PP
.B User Request Primitives
.IP \(em 4
.BR N_UNITDATA_REQ (7):
This primitive requests that the NS provider send the data unit to the
specified destination.
.PP
.B Provider Response Primitives
.IP \(em 4
.BR N_UNITDATA_IND (7):
This primitive indicates to the NS user that a data unit has been received
from the specified source address.
.IP \(em 4
.BR N_UDERROR_IND (7):
This primitive indicates to the NS user that the data unit
with the specified destination address and QOS parameters produced an error.
This primitive is specific to CLNS.
.\"
.\"
.\"
.\"
.SS "Local Management"
The following management primitives are common to all modes of network service
provider.
.IP \(em 4
.BR N_INFO_ACK (7):
Requests information concerning the communications device, provider limits,
styles and features.
.IP \(em 4
.BR N_INFO_REQ (7):
Provides information concerning the communications device, provider limits,
styles and features.
.IP \(em 4
.BR N_OPTMGMT_REQ (7):
Requests the management of network provider options.
.IP \(em 4
.BR N_BIND_REQ (7):
Requests the binding of the stream to a network endpoint address.
.IP \(em 4
.BR N_BIND_ACK (7):
Provides acknowledgment of the bound network endpoint address.
.IP \(em 4
.BR N_UNBIND_REQ (7):
Requests the stream be unbound from the bound network endpoint address.
.IP \(em 4
.BR N_OK_ACK (7):
Provides positive acknowledgment of request primitives that require
acknowledgment.
.IP \(em 4
.BR N_ERROR_ACK (7):
Provides negative acknowledgment of request primitives that require
acknowledgment.
.SS "Connectionless Data Transfer"
The following primitives provide for the transfer of data with a
connectionless network service provider.
.IP \(em 4
.BR N_UNITDATA_REQ (7):
Requests the transmission of connectionless data.
.IP \(em 4
.BR N_UNITDATA_IND (7):
Provides indication of the reception of connectionless data.
.IP \(em 4
.BR N_UDERROR_IND (7):
Provides indication of errors encountered in the transmission of
connectionless data.
.SS "Connection Establishment"
The following primitives establish a network connection with a connection
oriented network service provider.
.IP \(em 4
.BR N_CONN_REQ (7):
Requests connection to a peer network endpoint.
.IP \(em 4
.BR N_CONN_CON (7):
Provides confirmation of a connection request.
.IP \(em 4
.BR N_CONN_IND (7):
Provides indication of a connection request from a peer endpoint.
.IP \(em 4
.BR N_CONN_RES (7):
Responds to an outstanding connection indication.
.SS "Connection Data Transfer"
The following primitives provide for the transfer of data with a connection
oriented network service provider.
.PP
.B Data Transfer Service.
The following primitives provide for the transfer of data on the network
connection.
.IP \(em 4
.BR N_DATA_REQ (7):
Requests the transmission of data on a network connection.
.IP \(em 4
.BR N_DATA_IND (7):
Provides indication of the reception of data on a network connection.
.IP \(em 4
.BR N_EXDATA_REQ (7):
Requests the transmission of expedited data on a network connection.
.IP \(em 4
.BR N_EXDATA_IND (7):
Provides indication of the reception of expedited data on a network
connection.
.PP
.B Data Acknowledgment Service.
The following primitives provider for the acknowledgment of data transfer.
.IP \(em 4
.BR N_DATACK_REQ (7):
Requests acknowledgment of the last received data on the network connection.
.IP \(em 4
.BR N_DATACK_IND (7):
Provides indication of acknwowldgment of the last transmitted data on the
network connection.
.SS "Connection Reset"
The following primitives provide for the reset of the network connection.
.IP \(em 4
.BR N_RESET_REQ (7):
Requests that a network connection be reset.
.IP \(em 4
.BR N_RESET_CON (7):
Provides confirmation of the reset of the network connection.
.IP \(em 4
.BR N_RESET_IND (7):
Provides indication of the reset of a network connection.
.IP \(em 4
.BR N_RESET_RES (7):
Responds to an outstanding indication of network connection reset.
.SS "Connection Release"
The following primitives provide for the release of a network connection with
a connection oriented network service provider.
.IP \(em 4
.BR N_DISCON_REQ (7):
Requests that a network connection be released.
.IP \(em 4
.BR N_DISCON_IND (7):
Provides indication that a network connection has been released.
.SH "SEE ALSO"
.BR N_BIND_ACK (7),
.BR N_BIND_REQ (7),
.BR N_CONN_CON (7),
.BR N_CONN_IND (7),
.BR N_CONN_REQ (7),
.BR N_CONN_RES (7),
.BR N_DATACK_IND (7),
.BR N_DATACK_REQ (7),
.BR N_DATA_IND (7),
.BR N_DATA_REQ (7),
.BR N_DISCON_IND (7),
.BR N_DISCON_REQ (7),
.BR N_ERROR_ACK (7),
.BR N_EXDATA_IND (7),
.BR N_EXDATA_REQ (7),
.BR N_INFO_ACK (7),
.BR N_INFO_REQ (7),
.BR N_OK_ACK (7),
.BR N_OPTMGMT_REQ (7),
.BR N_RESET_CON (7),
.BR N_RESET_IND (7),
.BR N_RESET_REQ (7),
.BR N_RESET_RES (7),
.BR N_UDERROR_IND (7),
.BR N_UNBIND_REQ (7),
.BR N_UNITDATA_IND (7),
.BR N_UNITDATA_REQ (7).
.SH VERSIONS
.PP
This manpage was written for
.B LiS\c
.
.[
LiS
.]
.br
The Network Provider Interface first appeared in SVR 4.
.[
svr4
.]
.br
This interface conforms to NPI Revision 2.
.XX
.[
npi
.]
.[
magic
.]
.[
advprog
.]
.[
$LIST$
.]
.TA