Guralp Systems CMG-DCM build <10,000 User Manual
Page 213
Acquisition Modules and Platinum Firmware
Building Networks
Note: The username is the means by which the server refers to this
client.
Encryption key: GSTM communication is encrypted using TLS. Each end of
any GSTM link needs to be configured with the same pre-shared key. If the
server has already been configured, the server administrator will give you a
value for the “Encryption Key” field; Otherwise, enter a random string into
this field and let the person administering the server know what you have
used. A command-line tool, gstm-genpsk, is provided to generate suitable
random strings.
Link tab
Watchdog interval: If a configured link carries no traffic for an extended
period, the client will send “watchdog” packets to the server. This serves two
functions: it reassures the client that the link is still usable and it defeats any
“automatic disconnect on idle” mechanisms which may be active on some
links. The time, in seconds, between such watchdog probes can be
configured by entering a value in the “Watchdog interval” field.
Restart interval: If the GSTM link fails for any reason, it is automatically
restarted. There may be situations where the link cannot be restarted so, to
prevent almost continuous restart attempts and consequent processor
thrashing, a time delay is implemented between a link failure and a restart
attempt. This defaults to thirty seconds but a different value can be
configured if desired by entering it in the “Restart interval” field.
Failover services: If the watchdog packets do not elicit a response from the
server, the link is assumed to have failed and, optionally, an additional
service can be started in response. This will typically be another GSTM client
in order to establish a back-up link. The GSTM client to be started should be
identified here by its service descriptor, which takes the form
gstmclient.n where n is an integer: 0 denotes the first configured client
instance, 1 the second and so on.
213
Issue E - February 2014