The time interval to transmit 'Echo Request' message.
'Echo Response' message is normally received in response
to 'Echo Request' message. In the event of no response to
the 'Echo Request' message, a notification is generated
identifying the peer GSN (i.e. cGtpGSN Address), which
fails to respond.
This object can be retrieved only if
cGtpEchoRequestTimerEnable is set to 'true'.