[Clustering]: Openflow connections unstable with Lithium plugin

Build used :
===================
Karaf distro from latest ODL Beryllium master code

Test Type :
===================
switch connection stability in cluster.

Objective of test :
===================
verify if the switch connection is stable in cluster deployment without using OF-HA.

Test Steps :
============
1. Bring up healthy 3 node cluster say c1, c2 and c3.
2. Bring UP the mininet with following command and connect to controller c1(10.183.181.41),c2(10.183.181.42) and c3(10.183.181.43).Here each controller is connected with 20 switches.so overall 60 switches.
Below commands is used to connect 20 switches per controller.

sudo mn --custom /home/mininet/mininet/custom/mytopo.py --topo mytopo --controller remote,ip=10.183.181.41,port=6633 --switch ovsk,protocols=Openflow13

Note:mytopo.py is attached for quick reference.

3.Check if the configured count of switches have establised connection with the controller instances using netstat

netstat -pan | grep 6633 | grep ESTABLISHED | grep ovs-vswitchd | wc -l

Test Results:
=============

1. Without any flow traffic or LLDP traffic itself, switch connection keeps flapping with respect to the controller.
So the connection is not stable.
In real scenerio, this can trigger unnecessarily re-conciliation cycles with the switches.

2. Operational Datastore reflects totally different count of switches in inventory shards(perhaps this is a side effect of BZ-4576 - https://bugs.opendaylight.org/show_bug.cgi?id=4576)

Attaching all the karaf logs of 3 controller nodes and the netstat snaphot of switch connectivity.

Thanks & Regards,
Saibal Roy.