Expand Configuration and Management Manual (G06.24+)

Subsystem Description
Expand Configuration and Management Manual—523347-008
18-57
Sending and Receiving Data
The default connect timeout period is 60 seconds. You can alter the connect timeout
period with the Expand SCF TIMERRECONNECT attribute. (The TIMERRECONNECT
attribute does not correspond to an Expand modifier and can therefore be changed
only by using the SCF interface to the Expand subsystem.)
You can limit the number of times the Expand-over-IP line-handler process will send a
Connect Command frame by specifying the MAXRECONNECTS modifier. If you
specify MAXRECONNECTS, you can also control what happens after the reconnect
limit has been reached by specifying the AFTERMAXRETRIES_PASSIVE or
AFTERMAXRETRIES_DOWN modifier.
Sending and Receiving Data
Once a connection has been established, the local and remote Expand-over-IP line-
handler processes communicate through their associated NonStop TCP/IP, TCPSAM,
or TCP6SAM processes using the QIO mechanism. You can control how many packets
the Expand-over-IP line-handler process can send to the NonStop TCP/IP process
before waiting for a reply by specifying the TXWINDOW modifier.
To detect loss of connection through the IP network, the Expand-over-IP line-handler
process sends a Probe message to the remote Expand-over-IP line-handler process at
periodic intervals of inactivity.
If the Expand-over-IP line-handler process does not receive a response to its Probe
message, it will consider the line down after exceeding the maximum number of Probe
message retries.
The default inactivity interval (the amount of time the Expand-over-IP line-handler
process will wait before sending a Probe message to the remote Expand-over-IP line-
handler process) is 60 seconds. You can alter the inactivity interval with the Expand
SCF TIMERPROBE attribute.
The default number of Probe messages retries is 3. You can control the number of
times the Expand-over-IP line-handler process will retry Probe messages with the
Expand SCF RETRYPROBE attribute.
Note. The RXWINDOW modifier is meaningless for Expand-over-IP connections but is
provided to maintain commonality among the different line types. Because the Expand-over-IP
line-handler process uses QIO to communicate with the NonStop TCP/IP process and the
Parallel Library TCP/IP and NonStop TCP/IPv6 processes, the Expand-over-IP line-handler
process must read all the messages on its receive queue at one time; it cannot limit the
number of messages read to the RXWINDOW modifier value because of QIO limitations.