Expand Configuration and Management Manual (G06.24+)

Subsystem Description
Expand Configuration and Management Manual—523347-008
18-51
Connection Establishment
The Expand-over-NAM, Expand-over-ServerNet, or Expand-over-FOX line-handler
process accesses a subdevice by sending a bind request to the NAM process. A bind
request is roughly equivalent to an OPEN procedure. The Expand-over-NAM, Expand-
over-ServerNet, or Expand-over-FOX line-handler process will continue to send bind
requests to the NAM process at regular intervals (default intervals are 60 seconds for
Expand-over-ServerNet line-handler processes, 60 seconds for Expand-over-FOX line-
handler processes, and 30 seconds for Expand-over-NAM line-handler processes) until
the request is successful. There is no limit to the number of times the Expand-over-
NAM, Expand-over-ServerNet, or Expand-over-FOX line-handler process can retry the
bind request.
You can control the bind timeout period by setting the Expand SCF TIMERBIND
attribute. (The TIMERBIND attribute does not correspond to an Expand modifier and
can be changed only by using the SCF interface to the Expand subsystem.)
Once the Expand-over-NAM, Expand-over-ServerNet, or Expand-over-FOX line-
handler process has successfully bound to a subdevice, it attempts to establish a
connection through the NAM process to a neighbor Expand line-handler process.
There are two ways the Expand-over-NAM, Expand-over-ServerNet, or Expand-over-
FOX line-handler process can attempt to establish a call: active connect or passive
connect.
The default connect method is active connect. You can cause the Expand-over-NAM,
Expand-over-ServerNet, or Expand-over-FOX line-handler process to use the active
connect method by specifying the CONNECTTYPE_ACTIVEANDPASSIVE modifier.
Active Connect Request
When the Expand-over-NAM, Expand-over-ServerNet, or Expand-over-FOX line-
handler process issues an active connect request, the NAM process attempts to
initiate a connection. If the request is successful, the Expand-over-NAM, Expand-over-
ServerNet, or Expand-over-FOX line-handler process can begin sending and receiving
data over the connection.
If the request is not successful within a certain timeout period, the Expand-over-NAM,
Expand-over-ServerNet, or Expand-over-FOX line-handler process cancels the active
connect request and issues a passive connect request. When the NAM process
receives a passive connect request, it waits for an incoming connect request; this
waiting period allows the process to receive a connect request from a remote Expand-
over-NAM, Expand-over-ServerNet, or Expand-over-FOX line-handler process.
If the passive connect request is not successful within the timeout period, the Expand-
over-NAM, Expand-over-ServerNet, or Expand-over-FOX line-handler process will
issue another active connect request. The line-handler process will continue to
alternately issue active and passive connect requests until a request is successful.
The default connect timeout period is 60 seconds for Expand-over-ServerNet, 60
seconds for Expand-over-FOX, and 30 seconds for Expand-over-NAM line-handler
processes. You can control the connect timeout period by setting the Expand SCF
TIMERRECONNECT attribute. (The TIMERRECONNECT attribute does not