Quantum agent (OVS) terminates when there is no connectivity to the quantum plugin

Quatum agent (OVS) terminates after rebooting the appliance on which the Quantum service and plugin are running.

Trace from the agent is below:-
[node@dhcp-4-84 ~]$ sudo /usr/bin/quantum-openvswitch-agent /etc/quantum/plugins/openvswitch/ovs_quantum_plugin.ini
Traceback (most recent call last):
  File "/usr/bin/quantum-openvswitch-agent", line 24, in <module>
    main()
  File "/usr/lib/python2.7/site-packages/quantum/plugins/openvswitch/agent/ovs_quantum_agent.py", line 680, in main
    plugin.daemon_loop(db)
  File "/usr/lib/python2.7/site-packages/quantum/plugins/openvswitch/agent/ovs_quantum_agent.py", line 301, in daemon_loop
    db.commit()
  File "/usr/lib64/python2.7/site-packages/sqlalchemy/ext/sqlsoup.py", line 615, in commit
    self.session.commit()
  File "/usr/lib64/python2.7/site-packages/sqlalchemy/orm/scoping.py", line 114, in do
    return getattr(self.registry(), name)(*args, **kwargs)
  File "/usr/lib64/python2.7/site-packages/sqlalchemy/orm/session.py", line 655, in commit
    self.transaction.commit()
  File "/usr/lib64/python2.7/site-packages/sqlalchemy/orm/session.py", line 317, in commit
    t[1].commit()
  File "/usr/lib64/python2.7/site-packages/sqlalchemy/engine/base.py", line 2036, in commit
    self._do_commit()
  File "/usr/lib64/python2.7/site-packages/sqlalchemy/engine/base.py", line 2066, in _do_commit
    self.connection._commit_impl()
  File "/usr/lib64/python2.7/site-packages/sqlalchemy/engine/base.py", line 1278, in _commit_impl
    self.engine.dialect.do_commit(self.connection)
  File "/usr/lib64/python2.7/site-packages/sqlalchemy/engine/base.py", line 1039, in connection
    return self._revalidate_connection()
  File "/usr/lib64/python2.7/site-packages/sqlalchemy/engine/base.py", line 1045, in _revalidate_connection
    "Can't reconnect until invalid "
sqlalchemy.exc.InvalidRequestError: Can't reconnect until invalid transaction is rolled back
[node@dhcp-4-84 ~]$