This object will keep track of all the messages which are
responsible for path removal between the GSNs.
As long as context remain established, the path between the
GSNs is alive. In an instant where the last context is released
and the echo timer is not enabled, the path timer is started
within which the PDP context is expected to keep the path
live, when the timer expires, path is Removed.
Trigger Condition: This timer is triggered when the path
between the GSNs is removed.