The NSP module implements one of the protocols in the Transport layer
described by the Digital Network Architecture.
The entities that constitute the NSP module are listed below. The indention
indicates the hierarchical relationships between the entities.
NSP
Port
Local NSAP
Remote NSAP
NSP performs the following functions:
o Enables the creation and destruction of transport connections used for
sending messages within a network node and between network nodes.
o Manages the movement of expedited and normal data from transmit buffers
to receive buffers, using flow control mechanisms.
o Breaks up normal data messages into segments that can be transmitted
individually, and reassembles these segments into correct order after they
have been received.
o Guarantees the delivery of data and control messages to a specified
destination using an error correction mechanism.
The NSP entity is the top-level entity in the hierarchy of
entities belonging to the NSP module.
1 – character
ACKNOWLEDGMENT DELAY TIME
Default: 3 Value: 0-65
Maximum amount of time in seconds that an acknowledgment is to be
withheld. You cannot modify this characteristic.
CONGESTION AVOIDANCE
Default: True Value: Boolean
Enables the use of the automatic congestion avoidance mechanism. This
mechanism reduces the transport window size in response to an indication
from the Network layer.
DELAY FACTOR
Default: 2 Value: 2-15
Factor by which to multiply the current value of the roundtrip delay
estimate status attribute in order to set a value for the
retransmission timer.
NOTE - the roundtrip delay estimate is an attribute of the nsp port
entity.
DELAY WEIGHT
Default: 3 Value: 0-255
Relative weighting to apply to the current estimate and to a new sample
when estimating roundtrip delay.
DNA VERSION
Version number of the DNA NSP architecture specification to which the
implementation conforms. You cannot modify this characteristic.
KEEPALIVE TIME
Default: 60 Value: 1-65535
Time in seconds that NSP waits for data to be transmitted or received
before testing a transport connection. When this timer expires, NSP
sends a data request PDU to the remote NSP. This PDU does not change
the flow control parameters, but does require acknowledgment.
MAXIMUM RECEIVE BUFFERS
Default: 2000 Value: 1-65535
Maximum number of receive buffers that can store received transport PDUs.
You may not decrease the value while NSP is enabled.
MAXIMUM REMOTE NSAPS
Default: 201 Value: 1-65535
Maximum number of remote NSAPs that can exist concurrently. Must be
greater than the current value of maximum transport connections. You
can modify this characteristic to a lower value only when the entity is
disabled.
MAXIMUM TRANSPORT CONNECTIONS
Default: 200 Value: 0-65535
Maximum number of active transport connections allowed at one time.
Must not be less than the current value of maximum remote NSAPs. You may
not decrease the value while NSP is enabled.
MAXIMUM WINDOW
Default: 8 Value: 1-2047
Maximum credit window that can be granted on a transport connection.
This is used for control of the number of data segments PDUs allowed
to be transmitted over a particular transport connection before at least
one acknowledgment must be returned from the destination system. If the
number of PDUs already transmitted equals the maximum window and no
corresponding acknowledgments have been received, transport stops
sending PDUs over the transport connection and waits for an
acknowledgment message. You cannot modify this characteristic.
NSAP SELECTOR
Default: 32 Value: 0-256
NSAP selector used by the nsp entity when opening a port to a network
service. You cannot modify this characteristic.
RETRANSMIT THRESHOLD
Default: 5 Value: 1-65535
Maximum number of times a source nsp entity is to restart an expired
retransmission timer before the remote node is to be considered
unreachable. When the threshold is reached, NSP sets the confidence
variable to false.
2 – status
CURRENTLY ACTIVE CONNECTIONS
Number of active transport connections.
STATE
Status of the nsp entity.
OFF - The nsp entity is disabled.
ON - The nsp entity is enabled.
3 – local_nsap
An NSP Local NSAP entity is automatically created for each NSAP address
used by the nsp entity. Local NSAPs are used primarily to group together
remote NSAPs see the nsp local nsap remote nsap entity.
DELETED REMOTE NSAPS
Number of times a remote NSAP has been deleted in order to reclaim
resources.
NSAP ADDRESS
Address assigned to the local NSAP when it was created.
4 – loc_rmt
An NSP local NSAP remote NSAP entity maintains the transport counters and
generates events resulting from interactions between its superior local
NSAP and a remote transport service. The local nsap nsap-address refers
to the local NSAP associated with the specified remote NSAP.
4.1 – counter
CONNECTS RECEIVED
Total number of connect initiated CI messages, regardless of their
disposition, that the local service provider has received from the
remote service provider.
CONNECTS SENT
Total number of connect initiate CI messages, sent by the local
service provider to the remote service provider, including
retransmissions.
DUPLICATE PDUS RECEIVED
Total number of all types of detected duplicate transport PDUs received
from the remote service provider.
PDUS RECEIVED
Total number of all types of transport PDUs received from the remote
service provider excluding detected duplicates.
PDUS SENT
Total number of all types of transport PDUs sent to the remote service
provider excluding retransmissions.
REJECTS RECEIVED
Number of detected reject received events.
REJECTS SENT
Number of detected reject sent events.
REMOTE PROTOCOL ERRORS
Number of detected remote protocol error events.
RETRANSMITTED PDUS
Total number of all types of retransmitted transport PDUs sent to the
remote service provider.
TOTAL OCTETS RECEIVED
Total number of octets of all types of transport PDUs received from the
remote service provider, regardless of their disposition. This count
includes detected duplicates.
TOTAL OCTETS SENT
Total number of octets of all types of transport PDUs sent to the
remote service provider, including retransmissions.
USER OCTETS RECEIVED
Total number of user data octets received from the remote service
provider, including normal, expedited, connect, accept, and disconnect
data. This count does not include duplicates such as data retransmitted
by the remote service provider.
USER OCTETS SENT
Total number of user data octets sent to the remote service provider,
including normal, expedited, connect, accept, and disconnect data. This
count does not include data retransmitted by the local service provider.
USER PDUS DISCARDED
Number of PDUs received from the remote service provider that were
discarded because of insufficient buffer space.
USER PDUS RECEIVED
Total number of transport PDUs containing user data received from the
remote service provider, including normal, expedited, connect, accept,
and disconnect data. This count does not include duplicates such as
transport PDUs retransmitted by the remote service provider.
USER PDUS SENT
Total number of transport PDUs containing user data sent to the remote
service provider, including normal, expedited, connect, accept, and
disconnect data. This count does not include retransmitted transport
PDUs.
5 – port
An NSP Port entity represents one end of a transport connection and
maintains status information about that connection. A port is visible to
the network only when it is assigned to a transport connection.
5.1 – counter
DUPLICATE PDUS RECEIVED
Number of all types of detected duplicate transport PDUs received from
the remote service provider.
PDUS RECEIVED
Number of all types of transport PDUs received from the remote service
provider excluding detected duplicates.
PDUS SENT
Number of all types of transport PDUs sent to the remote service
provider excluding retransmissions.
RETRANSMITTED PDUS
Number of all types of retransmitted transport PDUs sent to the remote
service provider.
TOTAL OCTETS RECEIVED
Number of octets of all types of transport PDUs received from the remote
service provider, regardless of their disposition. This count includes
detected duplicates.
TOTAL OCTETS SENT
Number of octets of all types of transport PDUs sent to the remote
service provider, including retransmissions.
USER OCTETS RECEIVED
Number of user data octets received from the remote service provider,
including normal, expedited, connect, accept, and disconnect data. This
count does not include duplicates such as data retransmitted by the
remote service provider.
USER OCTETS SENT
Number of user data octets sent to the remote service provider,
including normal, expedited, connect, accept, and disconnect data. This
count does not include data retransmitted by the local service provider.
USER PDUS RECEIVED
Number of transport PDUs containing user data received from the remote
service provider, including normal, expedited, connect, accept, and
disconnect data. This count does not include duplicates such as
transport PDUs retransmitted by the remote service provider.
USER PDUS SENT
Number of transport PDUs containing user data sent to the remote service
provider, including normal, expedited, connect, accept, and disconnect
data. This count does not include retransmitted transport PDUs.
5.2 – status
CLIENT NAME
Name designated by the port user when the port was opened.
LOCAL NSAP
Local NSAP address being used for the transport connection.
LOCAL REFERENCE
Unique reference number assigned to the transport connection by the
local transport service provider.
NETWORK PORT
Name of the port being used.
REMOTE NSAP
Remote NSAP address being used for the transport connection.
REMOTE REFERENCE
Reference number assigned to the transport connection by the remote
transport service provider.
ROUNDTRIP DELAY ESTIMATE
Amount of time, in milliseconds, of the roundtrip delay on the transport
connection. Applicable only when operating class 4 protocol.