Issue in SNAT,DNAT communication - OCATA.

Set-up used :

Allinone node - Ocata devstack

One ODL with carbon version distro:
https://nexus.opendaylight.org/content/repositories/opendaylight.snapshot/org/opendaylight/integration/distribution-karaf/0.6.0-SNAPSHOT/distribution-karaf-0.6.0-20170522.002211-5360.zip

The below is the settings in Local.conf :

SERVICE_HOST=$HOST_IP
MYSQL_HOST=$SERVICE_HOST
RABBIT_HOST=$SERVICE_HOST
GLANCE_HOSTPORT=$SERVICE_HOST:9292
ADMIN_PASSWORD=secret
DATABASE_PASSWORD=secret
RABBIT_PASSWORD=secret
SERVICE_PASSWORD=secret

1. 1. Neutron options
      Q_USE_SECGROUP=True
      FLOATING_RANGE="11.12.13.0/24"
      IPV4_ADDRS_SAFE_TO_USE="10.0.0.0/22"
      Q_FLOATING_ALLOCATION_POOL=start=11.12.13.250,end=11.12.13.254
      PUBLIC_NETWORK_GATEWAY="11.12.13.1"
      PUBLIC_INTERFACE=eth0

1. Open vSwitch provider networking configuration
   Q_USE_PROVIDERNET_FOR_PUBLIC=True
   OVS_PHYSICAL_BRIDGE=br-ex
   PUBLIC_BRIDGE=br-ex
   ODL_PROVIDER_MAPPINGS=public:br-ex

LOGFILE=stack.sh.log
SCREEN_LOGDIR=/opt/stack/data/log
LOG_COLOR=True
RECLONE=yes
OFFLINE=False
disable_service swift
disable_service cinder
disable_service n-net
disable_service q-vpn
enable_service q-svc
enable_service q-dhcp
enable_service q-meta
enable_service n-cauth
enable_service tempest
enable_service n-cpu
enable_service placement-api

enable_plugin networking-odl https://github.com/openstack/networking-odl stable/ocata
NEUTRON_CREATE_INITIAL_NETWORKS=False
Q_PLUGIN=ml2
Q_ML2_TENANT_NETWORK_TYPE=vxlan
Q_OVS_USE_VETH=True

ENABLE_TENANT_TUNNELS=True

ODL_PORT=8080
ODL_MODE=externalodl
ODL_PORT_BINDING_CONTROLLER=network-topology

LIBVIRT_TYPE=qemu
ODL_MGR_IP=10.106.138.151

MYSQL_PASSWORD=mysql
RABBIT_PASSWORD=rabbit
SERVICE_TOKEN=service
SERVICE_PASSWORD=admin
ADMIN_PASSWORD=admin

LIBVIRT_TYPE=qemu

ODL_V2DRIVER=True
ODL_OVS_MANAGERS=10.106.138.151
PUBLIC_PHYSICAL_NETWORK=datacenter

PUBLIC_INTERFACE=ens35

[[post-config|/etc/neutron/plugins/ml2/ml2_conf.ini]]
[agent]
minimize_polling=True

[[post-config|/etc/neutron/dhcp_agent.ini]]
[DEFAULT]
force_metadata = True
enable_isolated_metadata = True

disable_service q-l3
[[post-config|$NEUTRON_CONF]]
[DEFAULT]
service_plugins = networking_odl.l3.l3_odl.OpenDaylightL3RouterPlugin
[[post-config|/etc/nova/nova.conf]]

[DEFAULT]
force_config_drive = False

Steps to reproduce the bug :

After stacking the devstack successfully,
Create an external network with network provider type flat and assign the subnet range

external network

neutron -v net-create public --router:external --provider:network_type=flat --provider:physical_network=datacenter

external network subnet:

neutron -v subnet-create public 11.12.13.0/24 --name external-subnet --gateway 11.12.13.250 --allocation-pool start=11.12.13.2,end=11.12.13.249

Then create the internal network and router in GUI.
Router set the gateway for the external network then add an interface for the internal network.

Create the floating ip

Now create a vm for the internal network and associate the floating ip to the vm.

Then from the VM instance ping or ssh the external network instance – SNAT scenario failed

Then from the external instance ping or ssh to the internal network vm – DNAT scenario failed