diff --git a/etc/quantum/plugins/nicira/nvp.ini b/etc/quantum/plugins/nicira/nvp.ini
index 506f486f96..904035df82 100644
--- a/etc/quantum/plugins/nicira/nvp.ini
+++ b/etc/quantum/plugins/nicira/nvp.ini
@@ -24,13 +24,19 @@ reconnect_interval = 2
 # sql_idle_timeout = 3600
 
 [NVP]
-# The number of logical ports to create per bridged logical switch
+# Maximum number of ports for each bridged logical switch
 # max_lp_per_bridged_ls = 64
+# Maximum number of ports for each overlay (stt, gre) logical switch
+# max_lp_per_overlay_ls = 256
 # Time from when a connection pool is switched to another controller
 # during failure.
 # failover_time = 5
 # Number of connects to each controller node.
 # concurrent_connections = 3
+# Name of the default cluster where requests should be sent if a nova zone id
+# is not specified. If it is empty or reference a non-existent cluster
+# the first cluster specified in this configuration file will be used
+# default_cluster_name =
 
 #[CLUSTER:example]
 # This is uuid of the default NVP Transport zone that will be used for
diff --git a/quantum/extensions/providernet.py b/quantum/extensions/providernet.py
index 204b7164c8..c259d3be8c 100644
--- a/quantum/extensions/providernet.py
+++ b/quantum/extensions/providernet.py
@@ -19,7 +19,9 @@ NETWORK_TYPE = 'provider:network_type'
 PHYSICAL_NETWORK = 'provider:physical_network'
 SEGMENTATION_ID = 'provider:segmentation_id'
 
-NETWORK_TYPE_VALUES = ['flat', 'gre', 'local', 'vlan']
+# TODO(salvatore-orlando): Devise a solution for allowing plugins
+# to alter the set of allowed values
+NETWORK_TYPE_VALUES = ['flat', 'gre', 'local', 'vlan', 'stt']
 
 EXTENDED_ATTRIBUTES_2_0 = {
     'networks': {
diff --git a/quantum/plugins/nicira/nicira_nvp_plugin/QuantumPlugin.py b/quantum/plugins/nicira/nicira_nvp_plugin/QuantumPlugin.py
index 5dd8563256..2838d1f35a 100644
--- a/quantum/plugins/nicira/nicira_nvp_plugin/QuantumPlugin.py
+++ b/quantum/plugins/nicira/nicira_nvp_plugin/QuantumPlugin.py
@@ -20,45 +20,54 @@
 # @author: Aaron Rosen, Nicira Networks, Inc.
 
 
-import ConfigParser
-import json
 import hashlib
 import logging
-import netaddr
-import os
-import sys
-import traceback
-import urllib
-import uuid
 
+import webob.exc
 
+# FIXME(salvatore-orlando): get rid of relative imports
 from common import config
 from quantum.plugins.nicira.nicira_nvp_plugin.api_client import client_eventlet
-import NvpApiClient
-import nvplib
 from nvp_plugin_version import PLUGIN_VERSION
 
+from quantum.plugins.nicira.nicira_nvp_plugin import nicira_models
+
+
 from quantum.api.v2 import attributes
+from quantum.api.v2 import base
 from quantum.common import constants
-from quantum.common import exceptions as exception
+from quantum.common import exceptions as q_exc
 from quantum.common import rpc as q_rpc
 from quantum.common import topics
 from quantum.db import api as db
 from quantum.db import db_base_plugin_v2
 from quantum.db import dhcp_rpc_base
 from quantum.db import models_v2
+from quantum.extensions import providernet as pnet
 from quantum.openstack.common import cfg
 from quantum.openstack.common import rpc
+from quantum import policy
+from quantum.plugins.nicira.nicira_nvp_plugin.common import (exceptions
+                                                             as nvp_exc)
+from quantum.plugins.nicira.nicira_nvp_plugin import nicira_db
+from quantum.plugins.nicira.nicira_nvp_plugin import nvp_cluster
+
+import NvpApiClient
+import nvplib
 
 
-CONFIG_FILE = "nvp.ini"
-CONFIG_FILE_PATHS = []
-if os.environ.get('QUANTUM_HOME', None):
-    CONFIG_FILE_PATHS.append('%s/etc' % os.environ['QUANTUM_HOME'])
-CONFIG_FILE_PATHS.append("/etc/quantum/plugins/nicira")
 LOG = logging.getLogger("QuantumPlugin")
 
 
+# Provider network extension - allowed network types for the NVP Plugin
+class NetworkTypes:
+    """ Allowed provider network types for the NVP Plugin """
+    STT = 'stt'
+    GRE = 'gre'
+    FLAT = 'flat'
+    VLAN = 'vlan'
+
+
 def parse_config():
     """Parse the supplied plugin configuration.
 
@@ -77,11 +86,7 @@ def parse_config():
         "sql_idle_timeout": cfg.CONF.DATABASE.sql_idle_timeout,
         "sql_dbpool_enable": cfg.CONF.DATABASE.sql_dbpool_enable
     }
-    nvp_options = {'max_lp_per_bridged_ls': cfg.CONF.NVP.max_lp_per_bridged_ls}
-    nvp_options.update({'failover_time': cfg.CONF.NVP.failover_time})
-    nvp_options.update({'concurrent_connections':
-                        cfg.CONF.NVP.concurrent_connections})
-
+    nvp_options = cfg.CONF.NVP
     nvp_conf = config.ClusterConfigOptions(cfg.CONF)
     cluster_names = config.register_cluster_groups(nvp_conf)
     nvp_conf.log_opt_values(LOG, logging.DEBUG)
@@ -116,125 +121,16 @@ class NVPRpcCallbacks(dhcp_rpc_base.DhcpRpcCallbackMixin):
         return q_rpc.PluginRpcDispatcher([self])
 
 
-class NVPCluster(object):
-    """Encapsulates controller connection and api_client for a cluster.
-
-    Accessed within the NvpPluginV2 class.
-
-    Each element in the self.controllers list is a dictionary that
-    contains the following keys:
-        ip, port, user, password, default_tz_uuid, uuid, zone
-
-    There may be some redundancy here, but that has been done to provide
-    future flexibility.
-    """
-    def __init__(self, name):
-        self._name = name
-        self.controllers = []
-        self.api_client = None
-
-    def __repr__(self):
-        ss = ['{ "NVPCluster": [']
-        ss.append('{ "name" : "%s" }' % self.name)
-        ss.append(',')
-        for c in self.controllers:
-            ss.append(str(c))
-            ss.append(',')
-        ss.append('] }')
-        return ''.join(ss)
-
-    def add_controller(self, ip, port, user, password, request_timeout,
-                       http_timeout, retries, redirects,
-                       default_tz_uuid, uuid=None, zone=None):
-        """Add a new set of controller parameters.
-
-        :param ip: IP address of controller.
-        :param port: port controller is listening on.
-        :param user: user name.
-        :param password: user password.
-        :param request_timeout: timeout for an entire API request.
-        :param http_timeout: timeout for a connect to a controller.
-        :param retries: maximum number of request retries.
-        :param redirects: maximum number of server redirect responses to
-            follow.
-        :param default_tz_uuid: default transport zone uuid.
-        :param uuid: UUID of this cluster (used in MDI configs).
-        :param zone: Zone of this cluster (used in MDI configs).
-        """
-
-        keys = [
-            'ip', 'user', 'password', 'default_tz_uuid', 'uuid', 'zone']
-        controller_dict = dict([(k, locals()[k]) for k in keys])
-
-        int_keys = [
-            'port', 'request_timeout', 'http_timeout', 'retries', 'redirects']
-        for k in int_keys:
-            controller_dict[k] = int(locals()[k])
-
-        self.controllers.append(controller_dict)
-
-    def get_controller(self, idx):
-        return self.controllers[idx]
-
-    @property
-    def name(self):
-        return self._name
-
-    @name.setter
-    def name(self, val=None):
-        self._name = val
-
-    @property
-    def host(self):
-        return self.controllers[0]['ip']
-
-    @property
-    def port(self):
-        return self.controllers[0]['port']
-
-    @property
-    def user(self):
-        return self.controllers[0]['user']
-
-    @property
-    def password(self):
-        return self.controllers[0]['password']
-
-    @property
-    def request_timeout(self):
-        return self.controllers[0]['request_timeout']
-
-    @property
-    def http_timeout(self):
-        return self.controllers[0]['http_timeout']
-
-    @property
-    def retries(self):
-        return self.controllers[0]['retries']
-
-    @property
-    def redirects(self):
-        return self.controllers[0]['redirects']
-
-    @property
-    def default_tz_uuid(self):
-        return self.controllers[0]['default_tz_uuid']
-
-    @property
-    def zone(self):
-        return self.controllers[0]['zone']
-
-    @property
-    def uuid(self):
-        return self.controllers[0]['uuid']
-
-
 class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
     """
     NvpPluginV2 is a Quantum plugin that provides L2 Virtual Network
     functionality using NVP.
     """
 
+    supported_extension_aliases = ["provider"]
+    # Default controller cluster
+    default_cluster = None
+
     def __init__(self, loglevel=None):
         if loglevel:
             logging.basicConfig(level=loglevel)
@@ -242,11 +138,11 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
             NvpApiClient.LOG.setLevel(loglevel)
 
         self.db_opts, self.nvp_opts, self.clusters_opts = parse_config()
-        self.clusters = []
+        self.clusters = {}
         for c_opts in self.clusters_opts:
             # Password is guaranteed to be the same across all controllers
             # in the same NVP cluster.
-            cluster = NVPCluster(c_opts['name'])
+            cluster = nvp_cluster.NVPCluster(c_opts['name'])
             for controller_connection in c_opts['nvp_controller_connection']:
                 args = controller_connection.split(':')
                 try:
@@ -259,7 +155,8 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
                                     "controller %(conn)s in cluster %(name)s"),
                                   {'conn': controller_connection,
                                    'name': c_opts['name']})
-                    raise
+                    raise nvp_exc.NvpInvalidConnection(
+                        conn_params=controller_connection)
 
             api_providers = [(x['ip'], x['port'], True)
                              for x in cluster.controllers]
@@ -269,29 +166,185 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
                 http_timeout=cluster.http_timeout,
                 retries=cluster.retries,
                 redirects=cluster.redirects,
-                failover_time=self.nvp_opts['failover_time'],
-                concurrent_connections=self.nvp_opts['concurrent_connections'])
+                failover_time=self.nvp_opts.failover_time,
+                concurrent_connections=self.nvp_opts.concurrent_connections)
 
             # TODO(salvatore-orlando): do login at first request,
-            # not when plugin, is instantiated
+            # not when plugin is instantiated
             cluster.api_client.login()
+            self.clusters[c_opts['name']] = cluster
 
-            # TODO(pjb): What if the cluster isn't reachable this
-            # instant?  It isn't good to fall back to invalid cluster
-            # strings.
-            # Default for future-versions
-            self.clusters.append(cluster)
-
-        # Connect and configure ovs_quantum db
+        # Connect and configure nvp_quantum db
         options = {
             'sql_connection': self.db_opts['sql_connection'],
             'sql_max_retries': self.db_opts['sql_max_retries'],
             'reconnect_interval': self.db_opts['reconnect_interval'],
             'base': models_v2.model_base.BASEV2,
         }
+        def_cluster_name = self.nvp_opts.default_cluster_name
+        if def_cluster_name and def_cluster_name in self.clusters:
+            self.default_cluster = self.clusters[def_cluster_name]
+        else:
+            first_cluster_name = self.clusters.keys()[0]
+            if not def_cluster_name:
+                LOG.info(_("Default cluster name not specified. "
+                           "Using first cluster:%s"), first_cluster_name)
+            elif not def_cluster_name in self.clusters:
+                LOG.warning(_("Default cluster name %(def_cluster_name)s. "
+                              "Using first cluster:%(first_cluster_name)s")
+                            % locals())
+            # otherwise set 1st cluster as default
+            self.default_cluster = self.clusters[first_cluster_name]
+
         db.configure_db(options)
+        # Extend the fault map
+        self._extend_fault_map()
+        # Set up RPC interface for DHCP agent
         self.setup_rpc()
 
+    def _extend_fault_map(self):
+        """ Extends the Quantum Fault Map
+
+        Exceptions specific to the NVP Plugin are mapped to standard
+        HTTP Exceptions
+        """
+        base.FAULT_MAP.update({nvp_exc.NvpInvalidNovaZone:
+                               webob.exc.HTTPBadRequest,
+                               nvp_exc.NvpNoMorePortsException:
+                               webob.exc.HTTPBadRequest})
+
+    def _novazone_to_cluster(self, novazone_id):
+        if novazone_id in self.novazone_cluster_map:
+            return self.novazone_cluster_map[novazone_id]
+        LOG.debug(_("Looking for nova zone: %s") % novazone_id)
+        for x in self.clusters:
+            LOG.debug(_("Looking for nova zone %(novazone_id)s in "
+                        "cluster: %(x)s") % locals())
+            if x.zone == str(novazone_id):
+                self.novazone_cluster_map[x.zone] = x
+                return x
+        LOG.error(_("Unable to find cluster config entry for nova zone: %s") %
+                  novazone_id)
+        raise nvp_exc.NvpInvalidNovaZone(nova_zone=novazone_id)
+
+    def _find_target_cluster(self, resource):
+        """ Return cluster where configuration should be applied
+
+        If the resource being configured has a paremeter expressing
+        the zone id (nova_id), then select corresponding cluster,
+        otherwise return default cluster.
+
+        """
+        if 'nova_id' in resource:
+            return self._novazone_to_cluster(resource['nova_id'])
+        else:
+            return self.default_cluster
+
+    def _check_provider_view_auth(self, context, network):
+        return policy.check(context,
+                            "extension:provider_network:view",
+                            network)
+
+    def _enforce_provider_set_auth(self, context, network):
+        return policy.enforce(context,
+                              "extension:provider_network:set",
+                              network)
+
+    def _handle_provider_create(self, context, attrs):
+        # NOTE(salvatore-orlando): This method has been borrowed from
+        # the OpenvSwtich plugin, altough changed to match NVP specifics.
+        network_type = attrs.get(pnet.NETWORK_TYPE)
+        physical_network = attrs.get(pnet.PHYSICAL_NETWORK)
+        segmentation_id = attrs.get(pnet.SEGMENTATION_ID)
+        network_type_set = attributes.is_attr_set(network_type)
+        physical_network_set = attributes.is_attr_set(physical_network)
+        segmentation_id_set = attributes.is_attr_set(segmentation_id)
+        if not (network_type_set or physical_network_set or
+                segmentation_id_set):
+            return
+
+        # Authorize before exposing plugin details to client
+        self._enforce_provider_set_auth(context, attrs)
+        err_msg = None
+        if not network_type_set:
+            err_msg = _("%s required") % pnet.NETWORK_TYPE
+        elif network_type in (NetworkTypes.GRE, NetworkTypes.STT,
+                              NetworkTypes.FLAT):
+            if segmentation_id_set:
+                err_msg = _("Segmentation ID cannot be specified with "
+                            "flat network type")
+        elif network_type == NetworkTypes.VLAN:
+            if not segmentation_id_set:
+                err_msg = _("Segmentation ID must be specified with "
+                            "vlan network type")
+            elif (segmentation_id_set and
+                  (segmentation_id < 1 or segmentation_id > 4094)):
+                err_msg = _("%s out of range (1 to 4094)") % segmentation_id
+            else:
+                # Verify segment is not already allocated
+                binding = nicira_db.get_network_binding_by_vlanid(
+                    context.session, segmentation_id)
+                if binding:
+                    raise q_exc.VlanIdInUse(vlan_id=segmentation_id,
+                                            physical_network=physical_network)
+        else:
+            err_msg = _("%(net_type_param)s %(net_type_value)s not "
+                        "supported") % {'net_type_param': pnet.NETWORK_TYPE,
+                                        'net_type_value': network_type}
+        if err_msg:
+            raise q_exc.InvalidInput(error_message=err_msg)
+        # TODO(salvatore-orlando): Validate tranport zone uuid
+        # which should be specified in physical_network
+
+    def _extend_network_dict_provider(self, context, network, binding=None):
+        if self._check_provider_view_auth(context, network):
+            if not binding:
+                binding = nicira_db.get_network_binding(context.session,
+                                                        network['id'])
+            # With NVP plugin 'normal' overlay networks will have no binding
+            # TODO(salvatore-orlando) make sure users can specify a distinct
+            # tz_uuid as 'provider network' for STT net type
+            if binding:
+                network[pnet.NETWORK_TYPE] = binding.binding_type
+                network[pnet.PHYSICAL_NETWORK] = binding.tz_uuid
+                network[pnet.SEGMENTATION_ID] = binding.vlan_id
+
+    def _handle_lswitch_selection(self, cluster, network,
+                                  network_binding, max_ports,
+                                  allow_extra_lswitches):
+        lswitches = nvplib.get_lswitches(cluster, network.id)
+        try:
+            # TODO find main_ls too!
+            return [ls for ls in lswitches
+                    if (ls['_relations']['LogicalSwitchStatus']
+                        ['lport_count'] < max_ports)].pop(0)
+        except IndexError:
+            # Too bad, no switch available
+            LOG.debug(_("No switch has available ports (%d checked)") %
+                      len(lswitches))
+        if allow_extra_lswitches:
+            main_ls = [ls for ls in lswitches if ls['uuid'] == network.id]
+            tag_dict = dict((x['scope'], x['tag']) for x in main_ls[0]['tags'])
+            if not 'multi_lswitch' in tag_dict:
+                nvplib.update_lswitch(cluster,
+                                      main_ls[0]['uuid'],
+                                      main_ls[0]['display_name'],
+                                      network['tenant_id'],
+                                      tags=[{'tag': 'True',
+                                             'scope': 'multi_lswitch'}])
+            selected_lswitch = nvplib.create_lswitch(
+                cluster, network.tenant_id,
+                "%s-ext-%s" % (network.name, len(lswitches)),
+                network_binding.binding_type,
+                network_binding.tz_uuid,
+                network_binding.vlan_id,
+                network.id)
+            return selected_lswitch
+        else:
+            LOG.error(_("Maximum number of logical ports reached for "
+                        "logical network %s") % network.id)
+            raise nvp_exc.NvpNoMorePortsException(network=network.id)
+
     def setup_rpc(self):
         # RPC support for dhcp
         self.topic = topics.PLUGIN
@@ -302,15 +355,6 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
         # Consume from all consumers in a thread
         self.conn.consume_in_thread()
 
-    @property
-    def cluster(self):
-        if len(self.clusters):
-            return self.clusters[0]
-        return None
-
-    def clear_state(self):
-        nvplib.clear_state(self.clusters[0])
-
     def get_all_networks(self, tenant_id, **kwargs):
         networks = []
         for c in self.clusters:
@@ -337,24 +381,40 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
                    }
         :raises: exception.NoImplementedError
         """
+        net_data = network['network'].copy()
+        # Process the provider network extension
+        self._handle_provider_create(context, net_data)
+        # Replace ATTR_NOT_SPECIFIED with None before sending to NVP
+        for attr, value in network['network'].iteritems():
+            if value == attributes.ATTR_NOT_SPECIFIED:
+                net_data[attr] = None
         # FIXME(arosen) implement admin_state_up = False in NVP
-        if network['network']['admin_state_up'] is False:
+        if net_data['admin_state_up'] is False:
             LOG.warning(_("Network with admin_state_up=False are not yet "
                           "supported by this plugin. Ignoring setting for "
-                          "network %s"),
-                        network['network'].get('name', '<unknown>'))
+                          "network %s") % net_data.get('name', '<unknown>'))
+        tenant_id = self._get_tenant_id_for_create(context, net_data)
+        target_cluster = self._find_target_cluster(net_data)
+        lswitch = nvplib.create_lswitch(target_cluster,
+                                        tenant_id,
+                                        net_data.get('name'),
+                                        net_data.get(pnet.NETWORK_TYPE),
+                                        net_data.get(pnet.PHYSICAL_NETWORK),
+                                        net_data.get(pnet.SEGMENTATION_ID))
+        network['network']['id'] = lswitch['uuid']
 
-        tenant_id = self._get_tenant_id_for_create(context, network)
-        # TODO(salvatore-orlando): if the network is shared this should be
-        # probably stored into the lswitch with a tag
-        # TODO(salvatore-orlando): Important - provider networks support
-        # (might require a bridged TZ)
-        net = nvplib.create_network(network['network']['tenant_id'],
-                                    network['network']['name'],
-                                    clusters=self.clusters)
-
-        network['network']['id'] = net['net-id']
-        return super(NvpPluginV2, self).create_network(context, network)
+        with context.session.begin(subtransactions=True):
+            new_net = super(NvpPluginV2, self).create_network(context,
+                                                              network)
+            if net_data.get(pnet.NETWORK_TYPE):
+                net_binding = nicira_db.add_network_binding(
+                    context.session, new_net['id'],
+                    net_data.get(pnet.NETWORK_TYPE),
+                    net_data.get(pnet.PHYSICAL_NETWORK),
+                    net_data.get(pnet.SEGMENTATION_ID))
+                self._extend_network_dict_provider(context, new_net,
+                                                   net_binding)
+        return new_net
 
     def delete_network(self, context, id):
         """
@@ -365,29 +425,31 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
         :raises: exception.NetworkInUse
         :raises: exception.NetworkNotFound
         """
-
         super(NvpPluginV2, self).delete_network(context, id)
+
+        # FIXME(salvatore-orlando): Failures here might lead NVP
+        # and quantum state to diverge
         pairs = self._get_lswitch_cluster_pairs(id, context.tenant_id)
         for (cluster, switches) in pairs:
             nvplib.delete_networks(cluster, id, switches)
 
-        LOG.debug(_("delete_network() completed for tenant: %s"),
+        LOG.debug(_("delete_network completed for tenant: %s"),
                   context.tenant_id)
 
     def _get_lswitch_cluster_pairs(self, netw_id, tenant_id):
         """Figure out the set of lswitches on each cluster that maps to this
            network id"""
         pairs = []
-        for c in self.clusters:
+        for c in self.clusters.itervalues():
             lswitches = []
             try:
-                ls = nvplib.get_network(c, netw_id)
-                lswitches.append(ls['uuid'])
-            except exception.NetworkNotFound:
+                results = nvplib.get_lswitches(c, netw_id)
+                lswitches.extend([ls['uuid'] for ls in results])
+            except q_exc.NetworkNotFound:
                 continue
             pairs.append((c, lswitches))
         if len(pairs) == 0:
-            raise exception.NetworkNotFound(net_id=netw_id)
+            raise q_exc.NetworkNotFound(net_id=netw_id)
         LOG.debug(_("Returning pairs for network: %s"), pairs)
         return pairs
 
@@ -414,55 +476,43 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
         :raises: exception.NetworkNotFound
         :raises: exception.QuantumException
         """
-        result = {}
-        lswitch_query = "&uuid=%s" % id
-        # always look for the tenant_id in the resource itself rather than
-        # the context, as with shared networks context.tenant_id and
-        # network['tenant_id'] might differ on GETs
         # goto to the plugin DB and fecth the network
         network = self._get_network(context, id)
-        # TODO(salvatore-orlando): verify whether the query on os_tid is
-        # redundant or not.
-        if context.is_admin is False:
-            tenant_query = ("&tag=%s&tag_scope=os_tid"
-                            % network['tenant_id'])
-        else:
-            tenant_query = ""
-        # Then fetch the correspondiong logical switch in NVP as well
-        # TODO(salvatore-orlando): verify whether the step on NVP
-        # can be completely avoided
-        lswitch_url_path = (
-            "/ws.v1/lswitch?"
-            "fields=uuid,display_name%s%s"
-            % (tenant_query, lswitch_query))
+
+        # verify the fabric status of the corresponding
+        # logical switch(es) in nvp
         try:
-            for c in self.clusters:
-                lswitch_results = nvplib.get_all_query_pages(
-                    lswitch_url_path, c)
-                if lswitch_results:
-                    result['lswitch-display-name'] = (
-                        lswitch_results[0]['display_name'])
+            # FIXME(salvatore-orlando): This is not going to work unless
+            # nova_id is stored in db once multiple clusters are enabled
+            cluster = self._find_target_cluster(network)
+            lswitches = nvplib.get_lswitches(cluster, id)
+            net_op_status = constants.NET_STATUS_ACTIVE
+            quantum_status = network.status
+            for lswitch in lswitches:
+                lswitch_status = lswitch.get('LogicalSwitchStatus', None)
+                # FIXME(salvatore-orlando): Being unable to fetch the
+                # logical switch status should be an exception.
+                if (lswitch_status and
+                    not lswitch_status.get('fabric_status', None)):
+                    net_op_status = constants.NET_STATUS_DOWN
                     break
+            LOG.debug(_("Current network status:%(net_op_status)s; "
+                        "Status in Quantum DB:%(quantum_status)s")
+                      % locals())
+            if net_op_status != network.status:
+                # update the network status
+                with context.session.begin(subtransactions=True):
+                    network.status = net_op_status
         except Exception:
-            LOG.error(_("Unable to get switches: %s"), traceback.format_exc())
-            raise exception.QuantumException()
+            err_msg = _("Unable to get lswitches")
+            LOG.exception(err_msg)
+            raise nvp_exc.NvpPluginException(err_msg=err_msg)
 
-        if 'lswitch-display-name' not in result:
-            raise exception.NetworkNotFound(net_id=id)
-
-        # Fetch network in quantum
-        quantum_db = super(NvpPluginV2, self).get_network(context, id, fields)
-        d = {'id': id,
-             'name': result['lswitch-display-name'],
-             'tenant_id': network['tenant_id'],
-             'admin_state_up': True,
-             'status': constants.NET_STATUS_ACTIVE,
-             'shared': network['shared'],
-             'subnets': quantum_db.get('subnets', [])}
-
-        LOG.debug(_("get_network() completed for tenant %(tenant_id)s: %(d)s"),
-                  {'tenant_id': context.tenant_id, 'd': d})
-        return d
+        # Don't do field selection here otherwise we won't be able
+        # to add provider networks fields
+        net_result = self._make_network_dict(network, None)
+        self._extend_network_dict_provider(context, net_result)
+        return self._fields(net_result, fields)
 
     def get_networks(self, context, filters=None, fields=None):
         """
@@ -491,6 +541,8 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
         nvp_lswitches = []
         quantum_lswitches = (
             super(NvpPluginV2, self).get_networks(context, filters))
+        for net in quantum_lswitches:
+            self._extend_network_dict_provider(context, net)
 
         if context.is_admin and not filters.get("tenant_id"):
             tenant_filter = ""
@@ -501,19 +553,20 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
         else:
             tenant_filter = "&tag=%s&tag_scope=os_tid" % context.tenant_id
 
-        lswitch_filters = "uuid,display_name,fabric_status"
+        lswitch_filters = "uuid,display_name,fabric_status,tags"
         lswitch_url_path = (
             "/ws.v1/lswitch?fields=%s&relations=LogicalSwitchStatus%s"
             % (lswitch_filters, tenant_filter))
         try:
-            for c in self.clusters:
+            for c in self.clusters.itervalues():
                 res = nvplib.get_all_query_pages(
                     lswitch_url_path, c)
 
                 nvp_lswitches.extend(res)
         except Exception:
-            LOG.error(_("Unable to get switches: %s"), traceback.format_exc())
-            raise exception.QuantumException()
+            err_msg = _("Unable to get logical switches")
+            LOG.exception(err_msg)
+            raise nvp_exc.NvpPluginException(err_msg=err_msg)
 
         # TODO (Aaron) This can be optimized
         if filters.get("id"):
@@ -525,9 +578,9 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
             nvp_lswitches = filtered_lswitches
 
         for quantum_lswitch in quantum_lswitches:
-            Found = False
             for nvp_lswitch in nvp_lswitches:
-                if nvp_lswitch["uuid"] == quantum_lswitch["id"]:
+                # TODO(salvatore-orlando): watch out for "extended" lswitches
+                if nvp_lswitch['uuid'] == quantum_lswitch["id"]:
                     if (nvp_lswitch["_relations"]["LogicalSwitchStatus"]
                             ["fabric_status"]):
                         quantum_lswitch["status"] = constants.NET_STATUS_ACTIVE
@@ -535,12 +588,9 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
                         quantum_lswitch["status"] = constants.NET_STATUS_DOWN
                     quantum_lswitch["name"] = nvp_lswitch["display_name"]
                     nvp_lswitches.remove(nvp_lswitch)
-                    Found = True
                     break
-
-            if not Found:
-                raise Exception(_("Quantum and NVP Databases are out of "
-                                  "Sync!"))
+            else:
+                raise nvp_exc.NvpOutOfSyncException()
         # do not make the case in which switches are found in NVP
         # but not in Quantum catastrophic.
         if len(nvp_lswitches):
@@ -587,9 +637,9 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
 
         if network["network"].get("admin_state_up"):
             if network['network']["admin_state_up"] is False:
-                raise exception.NotImplementedError("admin_state_up=False "
-                                                    "networks are not "
-                                                    "supported.")
+                raise q_exc.NotImplementedError(_("admin_state_up=False "
+                                                  "networks are not "
+                                                  "supported."))
         params = {}
         params["network"] = network["network"]
         pairs = self._get_lswitch_cluster_pairs(id, context.tenant_id)
@@ -598,7 +648,8 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
         if network['network'].get("name"):
             for (cluster, switches) in pairs:
                 for switch in switches:
-                    result = nvplib.update_network(cluster, switch, **params)
+                    nvplib.update_lswitch(cluster, switch,
+                                          network['network']['name'])
 
         LOG.debug(_("update_network() completed for tenant: %s"),
                   context.tenant_id)
@@ -653,7 +704,7 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
         lport_fields_str = ("tags,admin_status_enabled,display_name,"
                             "fabric_status_up")
         try:
-            for c in self.clusters:
+            for c in self.clusters.itervalues():
                 lport_query_path = (
                     "/ws.v1/lswitch/%s/lport?fields=%s&%s%stag_scope=q_port_id"
                     "&relations=LogicalPortStatus" %
@@ -667,8 +718,9 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
                                 nvp_lports[tag["tag"]] = port
 
         except Exception:
-            LOG.error(_("Unable to get ports: %s"), traceback.format_exc())
-            raise exception.QuantumException()
+            err_msg = _("Unable to get ports")
+            LOG.exception(err_msg)
+            raise nvp_exc.NvpPluginException(err_msg=err_msg)
 
         lports = []
         for quantum_lport in quantum_lports:
@@ -690,8 +742,10 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
                 del nvp_lports[quantum_lport["id"]]
                 lports.append(quantum_lport)
             except KeyError:
-                raise Exception(_("Quantum and NVP Databases are out of "
-                                  "Sync!"))
+
+                LOG.debug(_("Quantum logical port %s was not found on NVP"),
+                          quantum_lport['id'])
+
         # do not make the case in which ports are found in NVP
         # but not in Quantum catastrophic.
         if len(nvp_lports):
@@ -721,8 +775,7 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
          "admin_state_up": Sets admin state of port. if down, port
                            does not forward packets.
          "status": dicates whether port is currently operational
-                   (limit values to "ACTIVE", "DOWN", "BUILD", and
-                   "ERROR"?)
+                   (limit values to "ACTIVE", "DOWN", "BUILD", and "ERROR")
          "fixed_ips": list of subnet ID's and IP addresses to be used on
                       this port
          "device_id": identifies the device (e.g., virtual server) using
@@ -732,46 +785,70 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
         :raises: exception.NetworkNotFound
         :raises: exception.StateInvalid
         """
-
+        tenant_id = self._get_tenant_id_for_create(context, port['port'])
         # Set admin_state_up False since not created in NVP set
+        # TODO(salvatore-orlando) : verify whether subtransactions can help
+        # us avoiding multiple operations on the db. This might also allow
+        # us to use the same identifier for the NVP and the Quantum port
+        # Set admin_state_up False since not created in NVP yet
         port["port"]["admin_state_up"] = False
 
         # First we allocate port in quantum database
-        try:
-            quantum_db = super(NvpPluginV2, self).create_port(context, port)
-        except Exception as e:
-            raise e
+        quantum_db = super(NvpPluginV2, self).create_port(context, port)
 
-        # Update fields obtained from quantum db
+        # Update fields obtained from quantum db (eg: MAC address)
         port["port"].update(quantum_db)
-
         # We want port to be up in NVP
         port["port"]["admin_state_up"] = True
-        params = {}
-        params["max_lp_per_bridged_ls"] = \
-            self.nvp_opts["max_lp_per_bridged_ls"]
-        params["port"] = port["port"]
-        params["clusters"] = self.clusters
-        tenant_id = self._get_tenant_id_for_create(context, port["port"])
-
+        port_data = port['port']
+        # Fetch the network and network binding from Quantum db
+        network = self._get_network(context, port_data['network_id'])
+        network_binding = nicira_db.get_network_binding(
+            context.session, port_data['network_id'])
+        max_ports = self.nvp_opts.max_lp_per_overlay_ls
+        allow_extra_lswitches = False
+        if (network_binding and
+            network_binding.binding_type in (NetworkTypes.FLAT,
+                                             NetworkTypes.VLAN)):
+            max_ports = self.nvp_opts.max_lp_per_bridged_ls
+            allow_extra_lswitches = True
         try:
-            port["port"], nvp_port_id = nvplib.create_port(tenant_id,
-                                                           **params)
-            nvplib.plug_interface(self.clusters, port["port"]["network_id"],
-                                  nvp_port_id, "VifAttachment",
-                                  port["port"]["id"])
-        except Exception as e:
-            # failed to create port in NVP delete port from quantum_db
+            q_net_id = port_data['network_id']
+            cluster = self._find_target_cluster(port_data)
+            selected_lswitch = self._handle_lswitch_selection(
+                cluster, network, network_binding, max_ports,
+                allow_extra_lswitches)
+            lswitch_uuid = selected_lswitch['uuid']
+            lport = nvplib.create_lport(cluster,
+                                        lswitch_uuid,
+                                        port_data['tenant_id'],
+                                        port_data['id'],
+                                        port_data['name'],
+                                        port_data['device_id'],
+                                        port_data['admin_state_up'],
+                                        port_data['mac_address'],
+                                        port_data['fixed_ips'])
+            # Get NVP ls uuid for quantum network
+            nvplib.plug_interface(cluster, selected_lswitch['uuid'],
+                                  lport['uuid'], "VifAttachment",
+                                  port_data['id'])
+        except nvp_exc.NvpNoMorePortsException as e:
+            LOG.error(_("Number of available ports for network %s exhausted"),
+                      port_data['network_id'])
             super(NvpPluginV2, self).delete_port(context, port["port"]["id"])
             raise e
+        except Exception:
+            # failed to create port in NVP delete port from quantum_db
+            err_msg = _("An exception occured while plugging the interface "
+                        "in NVP for port %s") % port_data['id']
+            LOG.exception(err_msg)
+            super(NvpPluginV2, self).delete_port(context, port["port"]["id"])
+            raise nvp_exc.NvpPluginException(err_desc=err_msg)
 
-        d = {"port-id": port["port"]["id"],
-             "port-op-status": port["port"]["status"]}
+        LOG.debug(_("create_port completed on NVP for tenant %(tenant_id)s: "
+                    "(%(id)s)") % port_data)
 
-        LOG.debug(_("create_port() completed for tenant %(tenant_id)s: %(d)s"),
-                  locals())
-
-        # update port with admin_state_up True
+        # update port on Quantum DB with admin_state_up True
         port_update = {"port": {"admin_state_up": True}}
         return super(NvpPluginV2, self).update_port(context,
                                                     port["port"]["id"],
@@ -803,23 +880,17 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
         """
         params = {}
 
-        quantum_db = super(NvpPluginV2, self).get_port(context, id)
+        port_quantum = super(NvpPluginV2, self).get_port(context, id)
 
         port_nvp, cluster = (
-            nvplib.get_port_by_quantum_tag(self.clusters,
-                                           quantum_db["network_id"], id))
-
-        LOG.debug(_("Update port request: %s"), params)
+            nvplib.get_port_by_quantum_tag(self.clusters.itervalues(),
+                                           port_quantum["network_id"], id))
 
         params["cluster"] = cluster
-        params["port"] = port["port"]
-        params["port"]["id"] = quantum_db["id"]
-        params["port"]["tenant_id"] = quantum_db["tenant_id"]
-        result = nvplib.update_port(quantum_db["network_id"],
-                                    port_nvp["uuid"], **params)
-        LOG.debug(_("update_port() completed for tenant: %s"),
-                  context.tenant_id)
-
+        params["port"] = port_quantum
+        LOG.debug(_("Update port request: %s"), params)
+        nvplib.update_port(port_quantum['network_id'],
+                           port_nvp['uuid'], **params)
         return super(NvpPluginV2, self).update_port(context, id, port)
 
     def delete_port(self, context, id):
@@ -835,10 +906,11 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
         :raises: exception.NetworkNotFound
         """
 
-        port, cluster = nvplib.get_port_by_quantum_tag(self.clusters,
-                                                       '*', id)
+        # TODO(salvatore-orlando): pass only actual cluster
+        port, cluster = nvplib.get_port_by_quantum_tag(
+            self.clusters.itervalues(), '*', id)
         if port is None:
-            raise exception.PortNotFound(port_id=id)
+            raise q_exc.PortNotFound(port_id=id)
         # TODO(bgh): if this is a bridged network and the lswitch we just got
         # back will have zero ports after the delete we should garbage collect
         # the lswitch.
@@ -867,9 +939,11 @@ class NvpPluginV2(db_base_plugin_v2.QuantumDbPluginV2):
 
         quantum_db = super(NvpPluginV2, self).get_port(context, id, fields)
 
+        #TODO: pass only the appropriate cluster here
+        #Look for port in all lswitches
         port, cluster = (
-            nvplib.get_port_by_quantum_tag(self.clusters,
-                                           quantum_db["network_id"], id))
+            nvplib.get_port_by_quantum_tag(self.clusters.itervalues(),
+                                           "*", id))
 
         quantum_db["admin_state_up"] = port["admin_status_enabled"]
         if port["_relations"]["LogicalPortStatus"]["fabric_status_up"]:
diff --git a/quantum/plugins/nicira/nicira_nvp_plugin/api_client/client_eventlet.py b/quantum/plugins/nicira/nicira_nvp_plugin/api_client/client_eventlet.py
index a094644fce..75d0347669 100644
--- a/quantum/plugins/nicira/nicira_nvp_plugin/api_client/client_eventlet.py
+++ b/quantum/plugins/nicira/nicira_nvp_plugin/api_client/client_eventlet.py
@@ -28,7 +28,7 @@ from common import _conn_str
 eventlet.monkey_patch()
 
 logging.basicConfig(level=logging.INFO)
-lg = logging.getLogger('nvp_api_client')
+LOG = logging.getLogger(__name__)
 
 # Default parameters.
 DEFAULT_FAILOVER_TIME = 5
@@ -156,19 +156,19 @@ class NvpApiClientEventlet(object):
                  api_providers are configured.
         '''
         if not self._api_providers:
-            lg.warn(_("[%d] no API providers currently available."), rid)
+            LOG.warn(_("[%d] no API providers currently available."), rid)
             return None
 
         # The sleep time is to give controllers time to become consistent after
         # there has been a change in the controller used as the api_provider.
         now = time.time()
         if now < getattr(self, '_issue_conn_barrier', now):
-            lg.warn(_("[%d] Waiting for failover timer to expire."), rid)
+            LOG.warn(_("[%d] Waiting for failover timer to expire."), rid)
             time.sleep(self._issue_conn_barrier - now)
 
         # Print out a warning if all connections are in use.
         if self._conn_pool[self._active_conn_pool_idx].empty():
-            lg.debug(_("[%d] Waiting to acquire client connection."), rid)
+            LOG.debug(_("[%d] Waiting to acquire client connection."), rid)
 
         # Try to acquire a connection (block in get() until connection
         # available or timeout occurs).
@@ -178,19 +178,19 @@ class NvpApiClientEventlet(object):
         if active_conn_pool_idx != self._active_conn_pool_idx:
             # active_conn_pool became inactive while we were waiting.
             # Put connection back on old pool and try again.
-            lg.warn(_("[%(rid)d] Active pool expired while waiting for "
-                      "connection: %(conn)s"),
-                    {'rid': rid, 'conn': _conn_str(conn)})
+            LOG.warn(_("[%(rid)d] Active pool expired while waiting for "
+                       "connection: %(conn)s"),
+                     {'rid': rid, 'conn': _conn_str(conn)})
             self._conn_pool[active_conn_pool_idx].put(conn)
             return self.acquire_connection(rid=rid)
 
         # Check if the connection has been idle too long.
         now = time.time()
         if getattr(conn, 'last_used', now) < now - self.CONN_IDLE_TIMEOUT:
-            lg.info(_("[%(rid)d] Connection %(conn)s idle for %(sec)0.2f "
-                      "seconds; reconnecting."),
-                    {'rid': rid, 'conn': _conn_str(conn),
-                     'sec': now - conn.last_used})
+            LOG.info(_("[%(rid)d] Connection %(conn)s idle for %(sec)0.2f "
+                       "seconds; reconnecting."),
+                     {'rid': rid, 'conn': _conn_str(conn),
+                      'sec': now - conn.last_used})
             conn = self._create_connection(*self._conn_params(conn))
 
             # Stash conn pool so conn knows where to go when it releases.
@@ -198,9 +198,9 @@ class NvpApiClientEventlet(object):
 
         conn.last_used = now
         qsize = self._conn_pool[self._active_conn_pool_idx].qsize()
-        lg.debug(_("[%(rid)d] Acquired connection %(conn)s. %(qsize)d "
-                   "connection(s) available."),
-                 {'rid': rid, 'conn': _conn_str(conn), 'qsize': qsize})
+        LOG.debug(_("[%(rid)d] Acquired connection %(conn)s. %(qsize)d "
+                    "connection(s) available."),
+                  {'rid': rid, 'conn': _conn_str(conn), 'qsize': qsize})
         return conn
 
     def release_connection(self, http_conn, bad_state=False, rid=-1):
@@ -213,9 +213,9 @@ class NvpApiClientEventlet(object):
         :param rid: request id passed in from request eventlet.
         '''
         if self._conn_params(http_conn) not in self._api_providers:
-            lg.warn(_("[%(rid)d] Released connection '%(conn)s' is not an "
-                      "API provider for the cluster"),
-                    {'rid': rid, 'conn': _conn_str(http_conn)})
+            LOG.warn(_("[%(rid)d] Released connection '%(conn)s' is not an "
+                       "API provider for the cluster"),
+                     {'rid': rid, 'conn': _conn_str(http_conn)})
             return
 
         # Retrieve "home" connection pool.
@@ -223,9 +223,9 @@ class NvpApiClientEventlet(object):
         conn_pool = self._conn_pool[conn_pool_idx]
         if bad_state:
             # Reconnect to provider.
-            lg.warn(_("[%(rid)d] Connection returned in bad state, "
-                      "reconnecting to %(conn)s"),
-                    {'rid': rid, 'conn': _conn_str(http_conn)})
+            LOG.warn(_("[%(rid)d] Connection returned in bad state, "
+                       "reconnecting to %(conn)s"),
+                     {'rid': rid, 'conn': _conn_str(http_conn)})
             http_conn = self._create_connection(*self._conn_params(http_conn))
             http_conn.idx = conn_pool_idx
 
@@ -233,20 +233,20 @@ class NvpApiClientEventlet(object):
                 # This pool is no longer in a good state. Switch to next pool.
                 self._active_conn_pool_idx += 1
                 self._active_conn_pool_idx %= len(self._conn_pool)
-                lg.warn(_("[%(rid)d] Switched active_conn_pool from "
-                          "%(idx)d to %(pool_idx)d."),
-                        {'rid': rid, 'idx': http_conn.idx,
-                         'pool_idx': self._active_conn_pool_idx})
+                LOG.warn(_("[%(rid)d] Switched active_conn_pool from "
+                           "%(idx)d to %(pool_idx)d."),
+                         {'rid': rid, 'idx': http_conn.idx,
+                          'pool_idx': self._active_conn_pool_idx})
 
                 # No connections to the new provider allowed until after this
                 # timer has expired (allow time for synchronization).
                 self._issue_conn_barrier = time.time() + self._failover_time
 
         conn_pool.put(http_conn)
-        lg.debug(_("[%(rid)d] Released connection %(conn)s. "
-                   "%(qsize)d connection(s) available."),
-                 {'rid': rid, 'conn': _conn_str(http_conn),
-                  'qsize': conn_pool.qsize()})
+        LOG.debug(_("[%(rid)d] Released connection %(conn)s. "
+                    "%(qsize)d connection(s) available."),
+                  {'rid': rid, 'conn': _conn_str(http_conn),
+                   'qsize': conn_pool.qsize()})
 
     @property
     def need_login(self):
@@ -263,7 +263,7 @@ class NvpApiClientEventlet(object):
                 self.login()
                 self._doing_login_sem.release()
             else:
-                lg.debug(_("Waiting for auth to complete"))
+                LOG.debug(_("Waiting for auth to complete"))
                 self._doing_login_sem.acquire()
                 self._doing_login_sem.release()
         return self._cookie
@@ -277,13 +277,13 @@ class NvpApiClientEventlet(object):
 
         if ret:
             if isinstance(ret, Exception):
-                lg.error(_('NvpApiClient: login error "%s"'), ret)
+                LOG.error(_('NvpApiClient: login error "%s"'), ret)
                 raise ret
 
             self._cookie = None
             cookie = ret.getheader("Set-Cookie")
             if cookie:
-                lg.debug(_("Saving new authentication cookie '%s'"), cookie)
+                LOG.debug(_("Saving new authentication cookie '%s'"), cookie)
                 self._cookie = cookie
                 self._need_login = False
 
diff --git a/quantum/plugins/nicira/nicira_nvp_plugin/common/config.py b/quantum/plugins/nicira/nicira_nvp_plugin/common/config.py
index d4a88875a1..f0cd6b608a 100644
--- a/quantum/plugins/nicira/nicira_nvp_plugin/common/config.py
+++ b/quantum/plugins/nicira/nicira_nvp_plugin/common/config.py
@@ -40,8 +40,10 @@ database_opts = [
 
 nvp_opts = [
     cfg.IntOpt('max_lp_per_bridged_ls', default=64),
+    cfg.IntOpt('max_lp_per_overlay_ls', default=256),
     cfg.IntOpt('concurrent_connections', default=5),
-    cfg.IntOpt('failover_time', default=240)
+    cfg.IntOpt('failover_time', default=240),
+    cfg.StrOpt('default_cluster_name')
 ]
 
 cluster_opts = [
diff --git a/quantum/plugins/nicira/nicira_nvp_plugin/common/exceptions.py b/quantum/plugins/nicira/nicira_nvp_plugin/common/exceptions.py
new file mode 100644
index 0000000000..ed10c9b621
--- /dev/null
+++ b/quantum/plugins/nicira/nicira_nvp_plugin/common/exceptions.py
@@ -0,0 +1,42 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2012 Nicira Networks, Inc
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+""" NVP Plugin exceptions """
+
+from quantum.common import exceptions as q_exc
+
+
+class NvpPluginException(q_exc.QuantumException):
+    message = _("An unexpected error occurred in the NVP Plugin:%(err_desc)s")
+
+
+class NvpInvalidConnection(NvpPluginException):
+    message = _("Invalid NVP connection parameters: %(conn_params)s")
+
+
+class NvpInvalidNovaZone(NvpPluginException):
+    message = _("Unable to find cluster config entry "
+                "for nova zone: %(nova_zone)s")
+
+
+class NvpNoMorePortsException(NvpPluginException):
+    message = _("Unable to create port on network %(network)s. "
+                "Maximum number of ports reached")
+
+
+class NvpOutOfSyncException(NvpPluginException):
+    message = _("Quantum state has diverged from the networking backend!")
diff --git a/quantum/plugins/nicira/nicira_nvp_plugin/nicira_db.py b/quantum/plugins/nicira/nicira_nvp_plugin/nicira_db.py
new file mode 100644
index 0000000000..570e0bc0d5
--- /dev/null
+++ b/quantum/plugins/nicira/nicira_nvp_plugin/nicira_db.py
@@ -0,0 +1,54 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+# Copyright 2012 Nicira, Inc.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import logging
+
+from sqlalchemy.orm import exc
+
+import quantum.db.api as db
+from quantum.plugins.nicira.nicira_nvp_plugin import nicira_models
+
+LOG = logging.getLogger(__name__)
+
+
+def get_network_binding(session, network_id):
+    session = session or db.get_session()
+    try:
+        binding = (session.query(nicira_models.NvpNetworkBinding).
+                   filter_by(network_id=network_id).
+                   one())
+        return binding
+    except exc.NoResultFound:
+        return
+
+
+def get_network_binding_by_vlanid(session, vlan_id):
+    session = session or db.get_session()
+    try:
+        binding = (session.query(nicira_models.NvpNetworkBinding).
+                   filter_by(vlan_id=vlan_id).
+                   one())
+        return binding
+    except exc.NoResultFound:
+        return
+
+
+def add_network_binding(session, network_id, binding_type, tz_uuid, vlan_id):
+    with session.begin(subtransactions=True):
+        binding = nicira_models.NvpNetworkBinding(network_id, binding_type,
+                                                  tz_uuid, vlan_id)
+        session.add(binding)
+    return binding
diff --git a/quantum/plugins/nicira/nicira_nvp_plugin/nicira_models.py b/quantum/plugins/nicira/nicira_nvp_plugin/nicira_models.py
new file mode 100644
index 0000000000..256bb53163
--- /dev/null
+++ b/quantum/plugins/nicira/nicira_nvp_plugin/nicira_models.py
@@ -0,0 +1,49 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+# Copyright 2012 Nicira, Inc.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+
+from sqlalchemy import Column, Enum, ForeignKey, Integer, String
+
+from quantum.db.models_v2 import model_base
+
+
+class NvpNetworkBinding(model_base.BASEV2):
+    """Represents a binding of a virtual network with a transport zone.
+
+    This model class associates a Quantum network with a transport zone;
+    optionally a vlan ID might be used if the binding type is 'bridge'
+    """
+    __tablename__ = 'nvp_network_bindings'
+
+    network_id = Column(String(36),
+                        ForeignKey('networks.id', ondelete="CASCADE"),
+                        primary_key=True)
+    # 'flat', 'vlan', stt' or 'gre'
+    binding_type = Column(Enum('flat', 'vlan', 'stt', 'gre'), nullable=False)
+    tz_uuid = Column(String(36))
+    vlan_id = Column(Integer)
+
+    def __init__(self, network_id, binding_type, tz_uuid, vlan_id):
+        self.network_id = network_id
+        self.binding_type = binding_type
+        self.tz_uuid = tz_uuid
+        self.vlan_id = vlan_id
+
+    def __repr__(self):
+        return "<NetworkBinding(%s,%s,%s,%s)>" % (self.network_id,
+                                                  self.binding_type,
+                                                  self.tz_uuid,
+                                                  self.vlan_id)
diff --git a/quantum/plugins/nicira/nicira_nvp_plugin/nvp_cluster.py b/quantum/plugins/nicira/nicira_nvp_plugin/nvp_cluster.py
new file mode 100644
index 0000000000..a55f185a3f
--- /dev/null
+++ b/quantum/plugins/nicira/nicira_nvp_plugin/nvp_cluster.py
@@ -0,0 +1,131 @@
+# Copyright 2012 Nicira, Inc.
+# All Rights Reserved
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+#
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+#
+
+
+class NVPCluster(object):
+    """Encapsulates controller connection and api_client for a cluster.
+
+    Accessed within the NvpPluginV2 class.
+
+    Each element in the self.controllers list is a dictionary that
+    contains the following keys:
+        ip, port, user, password, default_tz_uuid, uuid, zone
+
+    There may be some redundancy here, but that has been done to provide
+    future flexibility.
+    """
+
+    def __init__(self, name):
+        self._name = name
+        self.controllers = []
+        self.api_client = None
+
+    def __repr__(self):
+        ss = ['{ "NVPCluster": [']
+        ss.append('{ "name" : "%s" }' % self.name)
+        ss.append(',')
+        for c in self.controllers:
+            ss.append(str(c))
+            ss.append(',')
+        ss.append('] }')
+        return ''.join(ss)
+
+    def add_controller(self, ip, port, user, password, request_timeout,
+                       http_timeout, retries, redirects,
+                       default_tz_uuid, uuid=None, zone=None):
+        """Add a new set of controller parameters.
+
+        :param ip: IP address of controller.
+        :param port: port controller is listening on.
+        :param user: user name.
+        :param password: user password.
+        :param request_timeout: timeout for an entire API request.
+        :param http_timeout: timeout for a connect to a controller.
+        :param retries: maximum number of request retries.
+        :param redirects: maximum number of server redirect responses to
+            follow.
+        :param default_tz_uuid: default transport zone uuid.
+        :param uuid: UUID of this cluster (used in MDI configs).
+        :param zone: Zone of this cluster (used in MDI configs).
+        """
+
+        keys = [
+            'ip', 'user', 'password', 'default_tz_uuid', 'uuid', 'zone']
+        controller_dict = dict([(k, locals()[k]) for k in keys])
+
+        int_keys = [
+            'port', 'request_timeout', 'http_timeout', 'retries', 'redirects']
+        for k in int_keys:
+            controller_dict[k] = int(locals()[k])
+
+        self.controllers.append(controller_dict)
+
+    def get_controller(self, idx):
+        return self.controllers[idx]
+
+    @property
+    def name(self):
+        return self._name
+
+    @name.setter
+    def name(self, val=None):
+        self._name = val
+
+    @property
+    def host(self):
+        return self.controllers[0]['ip']
+
+    @property
+    def port(self):
+        return self.controllers[0]['port']
+
+    @property
+    def user(self):
+        return self.controllers[0]['user']
+
+    @property
+    def password(self):
+        return self.controllers[0]['password']
+
+    @property
+    def request_timeout(self):
+        return self.controllers[0]['request_timeout']
+
+    @property
+    def http_timeout(self):
+        return self.controllers[0]['http_timeout']
+
+    @property
+    def retries(self):
+        return self.controllers[0]['retries']
+
+    @property
+    def redirects(self):
+        return self.controllers[0]['redirects']
+
+    @property
+    def default_tz_uuid(self):
+        return self.controllers[0]['default_tz_uuid']
+
+    @property
+    def zone(self):
+        return self.controllers[0]['zone']
+
+    @property
+    def uuid(self):
+        return self.controllers[0]['uuid']
diff --git a/quantum/plugins/nicira/nicira_nvp_plugin/nvplib.py b/quantum/plugins/nicira/nicira_nvp_plugin/nvplib.py
index edc56add30..5e7098088c 100644
--- a/quantum/plugins/nicira/nicira_nvp_plugin/nvplib.py
+++ b/quantum/plugins/nicira/nicira_nvp_plugin/nvplib.py
@@ -25,6 +25,7 @@
 
 from copy import copy
 import functools
+import itertools
 import json
 import hashlib
 import logging
@@ -33,6 +34,7 @@ import re
 import uuid
 
 from eventlet import semaphore
+
 import NvpApiClient
 
 #FIXME(danwent): I'd like this file to get to the point where it has
@@ -40,6 +42,17 @@ import NvpApiClient
 from quantum.common import constants
 from quantum.common import exceptions as exception
 
+# HTTP METHODS CONSTANTS
+HTTP_GET = "GET"
+HTTP_POST = "POST"
+# Default transport type for logical switches
+DEF_TRANSPORT_TYPE = "stt"
+# Prefix to be used for all NVP API calls
+URI_PREFIX = "/ws.v1"
+# Resources exposed by NVP API
+LSWITCH_RESOURCE = "lswitch"
+LPORT_RESOURCE = "lport"
+
 LOCAL_LOGGING = False
 if LOCAL_LOGGING:
     from logging.handlers import SysLogHandler
@@ -52,8 +65,8 @@ if LOCAL_LOGGING:
     LOG.addHandler(syslog)
     LOG.setLevel(logging.DEBUG)
 else:
-    LOG = logging.getLogger("nvplib")
-    LOG.setLevel(logging.INFO)
+    LOG = logging.getLogger(__name__)
+    LOG.setLevel(logging.DEBUG)
 
 # TODO(bgh): it would be more efficient to use a bitmap
 taken_context_ids = []
@@ -63,12 +76,42 @@ _net_type_cache = {}  # cache of {net_id: network_type}
 _lqueue_cache = {}
 
 
+def _build_uri_path(resource,
+                    resource_id=None,
+                    parent_resource_id=None,
+                    fields=None,
+                    relations=None, filters=None):
+    # TODO(salvatore-orlando): This is ugly. do something more clever
+    # and aovid the if statement
+    if resource == LPORT_RESOURCE:
+        res_path = ("%s/%s/%s" % (LSWITCH_RESOURCE,
+                                  parent_resource_id,
+                                  resource) +
+                    (resource_id and "/%s" % resource_id or ''))
+    else:
+        res_path = resource + (resource_id and
+                               "/%s" % resource_id or '')
+
+    params = []
+    params.append(fields and "fields=%s" % fields)
+    params.append(relations and "relations=%s" % relations)
+    if filters:
+        params.extend(['%s=%s' % (k, v) for (k, v) in filters.iteritems()])
+    uri_path = "%s/%s" % (URI_PREFIX, res_path)
+    query_string = reduce(lambda x, y: "%s&%s" % (x, y),
+                          itertools.ifilter(lambda x: x is not None, params),
+                          "")
+    if query_string:
+        uri_path += "?%s" % query_string
+    return uri_path
+
+
 def get_cluster_version(cluster):
     """Return major/minor version #"""
     # Get control-cluster nodes
     uri = "/ws.v1/control-cluster/node?_page_length=1&fields=uuid"
     try:
-        res = do_single_request("GET", uri, cluster=cluster)
+        res = do_single_request(HTTP_GET, uri, cluster=cluster)
         res = json.loads(res)
     except NvpApiClient.NvpApiException:
         raise exception.QuantumException()
@@ -79,7 +122,7 @@ def get_cluster_version(cluster):
     # running different version so we just need the first node version.
     uri = "/ws.v1/control-cluster/node/%s/status" % node_uuid
     try:
-        res = do_single_request("GET", uri, cluster=cluster)
+        res = do_single_request(HTTP_GET, uri, cluster=cluster)
         res = json.loads(res)
     except NvpApiClient.NvpApiException:
         raise exception.QuantumException()
@@ -97,7 +140,7 @@ def get_all_query_pages(path, c):
     while need_more_results:
         page_cursor_str = (
             "_page_cursor=%s" % page_cursor if page_cursor else "")
-        res = do_single_request("GET", "%s%s%s" %
+        res = do_single_request(HTTP_GET, "%s%s%s" %
                                 (path, query_marker, page_cursor_str),
                                 cluster=c)
         body = json.loads(res)
@@ -155,48 +198,83 @@ def find_lswitch_by_portid(clusters, port_id):
     return (None, None)
 
 
-def get_network(cluster, net_id):
-    path = "/ws.v1/lswitch/%s" % net_id
+def get_lswitches(cluster, quantum_net_id):
+    lswitch_uri_path = _build_uri_path(LSWITCH_RESOURCE, quantum_net_id,
+                                       relations="LogicalSwitchStatus")
+    results = []
     try:
-        resp_obj = do_single_request("GET", path, cluster=cluster)
-        network = json.loads(resp_obj)
-        LOG.warning(_("### nw:%s"), network)
-    except NvpApiClient.ResourceNotFound:
-        raise exception.NetworkNotFound(net_id=net_id)
-    except NvpApiClient.NvpApiException:
-        raise exception.QuantumException()
-    LOG.debug(_("Got network '%(net_id)s': %(network)s"), locals())
-    return network
-
-
-def create_lswitch(cluster, lswitch_obj):
-    LOG.info(_("Creating lswitch: %s"), lswitch_obj)
-    # Warn if no tenant is specified
-    found = "os_tid" in [x["scope"] for x in lswitch_obj["tags"]]
-    if not found:
-        LOG.warn(_("No tenant-id tag specified in logical switch: %s"),
-                 lswitch_obj)
-    uri = "/ws.v1/lswitch"
-    try:
-        resp_obj = do_single_request("POST", uri,
-                                     json.dumps(lswitch_obj),
+        resp_obj = do_single_request(HTTP_GET,
+                                     lswitch_uri_path,
                                      cluster=cluster)
+        ls = json.loads(resp_obj)
+        results.append(ls)
+        for tag in ls['tags']:
+            if (tag['scope'] == "multi_lswitch" and
+                tag['tag'] == "True"):
+                # Fetch extra logical switches
+                extra_lswitch_uri_path = _build_uri_path(
+                    LSWITCH_RESOURCE,
+                    fields="uuid,display_name,tags,lport_count",
+                    relations="LogicalSwitchStatus",
+                    filters={'tag': quantum_net_id,
+                             'tag_scope': 'quantum_net_id'})
+                extra_switches = get_all_query_pages(extra_lswitch_uri_path,
+                                                     cluster)
+                results.extend(extra_switches)
+        return results
     except NvpApiClient.NvpApiException:
+        # TODO(salvatore-olrando): Do a better exception handling
+        # and re-raising
+        LOG.exception(_("An error occured while fetching logical switches "
+                        "for Quantum network %s"), quantum_net_id)
         raise exception.QuantumException()
 
-    r = json.loads(resp_obj)
-    d = {}
-    d["net-id"] = r['uuid']
-    d["net-name"] = r['display_name']
-    LOG.debug(_("Created logical switch: %s"), d["net-id"])
-    return d
+
+def create_lswitch(cluster, tenant_id, display_name,
+                   transport_type=None,
+                   transport_zone_uuid=None,
+                   vlan_id=None,
+                   quantum_net_id=None,
+                   **kwargs):
+    nvp_binding_type = transport_type
+    if transport_type in ('flat', 'vlan'):
+        nvp_binding_type = 'bridge'
+    transport_zone_config = {"zone_uuid": (transport_zone_uuid or
+                                           cluster.default_tz_uuid),
+                             "transport_type": (nvp_binding_type or
+                                                DEF_TRANSPORT_TYPE)}
+    lswitch_obj = {"display_name": display_name,
+                   "transport_zones": [transport_zone_config],
+                   "tags": [{"tag": tenant_id, "scope": "os_tid"}]}
+    if nvp_binding_type == 'bridge' and vlan_id:
+        transport_zone_config["binding_config"] = {"vlan_translation":
+                                                   [{"transport": vlan_id}]}
+    if quantum_net_id:
+        lswitch_obj["tags"].append({"tag": quantum_net_id,
+                                    "scope": "quantum_net_id"})
+    if "tags" in kwargs:
+        lswitch_obj["tags"].extend(kwargs["tags"])
+    uri = _build_uri_path(LSWITCH_RESOURCE)
+    try:
+        lswitch_res = do_single_request(HTTP_POST, uri,
+                                        json.dumps(lswitch_obj),
+                                        cluster=cluster)
+    except NvpApiClient.NvpApiException:
+        raise exception.QuantumException()
+    lswitch = json.loads(lswitch_res)
+    LOG.debug(_("Created logical switch: %s") % lswitch['uuid'])
+    return lswitch
 
 
-def update_network(cluster, lswitch_id, **params):
-    uri = "/ws.v1/lswitch/" + lswitch_id
-    lswitch_obj = {}
-    if params["network"]["name"]:
-        lswitch_obj["display_name"] = params["network"]["name"]
+def update_lswitch(cluster, lswitch_id, display_name,
+                   tenant_id=None, **kwargs):
+    uri = _build_uri_path(LSWITCH_RESOURCE, resource_id=lswitch_id)
+    # TODO(salvatore-orlando): Make sure this operation does not remove
+    # any other important tag set on the lswtich object
+    lswitch_obj = {"display_name": display_name,
+                   "tags": [{"tag": tenant_id, "scope": "os_tid"}]}
+    if "tags" in kwargs:
+        lswitch_obj["tags"].extend(kwargs["tags"])
     try:
         resp_obj = do_single_request("PUT", uri, json.dumps(lswitch_obj),
                                      cluster=cluster)
@@ -262,26 +340,6 @@ def delete_networks(cluster, net_id, lswitch_ids):
             raise exception.QuantumException()
 
 
-def create_network(tenant_id, net_name, **kwargs):
-    clusters = kwargs["clusters"]
-    # Default to the primary cluster
-    cluster = clusters[0]
-
-    transport_zone = kwargs.get("transport_zone",
-                                cluster.default_tz_uuid)
-    transport_type = kwargs.get("transport_type", "stt")
-    lswitch_obj = {"display_name": net_name,
-                   "transport_zones": [
-                   {"zone_uuid": transport_zone,
-                    "transport_type": transport_type}
-                   ],
-                   "tags": [{"tag": tenant_id, "scope": "os_tid"}]}
-
-    net = create_lswitch(cluster, lswitch_obj)
-    net['net-op-status'] = constants.NET_STATUS_ACTIVE
-    return net
-
-
 def query_ports(cluster, network, relations=None, fields="*", filters=None):
     uri = "/ws.v1/lswitch/" + network + "/lport?"
     if relations:
@@ -328,7 +386,7 @@ def get_port_by_quantum_tag(clusters, lswitch, quantum_tag):
         if len(res["results"]) == 1:
             return (res["results"][0], c)
 
-    LOG.error(_("Port or Network not found, Error: %s"), str(e))
+    LOG.error(_("Port or Network not found"))
     raise exception.PortNotFound(port_id=quantum_tag, net_id=lswitch)
 
 
@@ -403,38 +461,32 @@ def update_port(network, port_id, **params):
     return obj
 
 
-def create_port(tenant, **params):
-    clusters = params["clusters"]
-    dest_cluster = clusters[0]  # primary cluster
-
-    ls_uuid = params["port"]["network_id"]
+def create_lport(cluster, lswitch_uuid, tenant_id, quantum_port_id,
+                 display_name, device_id, admin_status_enabled,
+                 mac_address=None, fixed_ips=None):
+    """ Creates a logical port on the assigned logical switch """
     # device_id can be longer than 40 so we rehash it
-    device_id = hashlib.sha1(params["port"]["device_id"]).hexdigest()
+    hashed_device_id = hashlib.sha1(device_id).hexdigest()
     lport_obj = dict(
-        admin_status_enabled=params["port"]["admin_state_up"],
-        display_name=params["port"]["name"],
-        tags=[dict(scope='os_tid', tag=tenant),
-              dict(scope='q_port_id', tag=params["port"]["id"]),
-              dict(scope='vm_id', tag=device_id)]
+        admin_status_enabled=admin_status_enabled,
+        display_name=display_name,
+        tags=[dict(scope='os_tid', tag=tenant_id),
+              dict(scope='q_port_id', tag=quantum_port_id),
+              dict(scope='vm_id', tag=hashed_device_id)],
     )
-    path = "/ws.v1/lswitch/" + ls_uuid + "/lport"
-
+    path = _build_uri_path(LPORT_RESOURCE, parent_resource_id=lswitch_uuid)
     try:
-        resp_obj = do_single_request("POST", path, json.dumps(lport_obj),
-                                     cluster=dest_cluster)
+        resp_obj = do_single_request("POST", path,
+                                     json.dumps(lport_obj),
+                                     cluster=cluster)
     except NvpApiClient.ResourceNotFound as e:
-        LOG.error("Network not found, Error: %s" % str(e))
-        raise exception.NetworkNotFound(net_id=params["port"]["network_id"])
-    except NvpApiClient.NvpApiException as e:
-        raise exception.QuantumException()
+        LOG.error("Logical switch not found, Error: %s" % str(e))
+        raise
 
     result = json.loads(resp_obj)
-    result['port-op-status'] = get_port_status(dest_cluster, ls_uuid,
-                                               result['uuid'])
-
-    params["port"].update({"admin_state_up": result["admin_status_enabled"],
-                           "status": result["port-op-status"]})
-    return (params["port"], result['uuid'])
+    LOG.debug("Created logical port %s on logical swtich %s"
+              % (result['uuid'], lswitch_uuid))
+    return result
 
 
 def get_port_status(cluster, lswitch_id, port_id):
@@ -455,10 +507,8 @@ def get_port_status(cluster, lswitch_id, port_id):
         return constants.PORT_STATUS_DOWN
 
 
-def plug_interface(clusters, lswitch_id, port, type, attachment=None):
-    dest_cluster = clusters[0]  # primary cluster
+def plug_interface(cluster, lswitch_id, port, type, attachment=None):
     uri = "/ws.v1/lswitch/" + lswitch_id + "/lport/" + port + "/attachment"
-
     lport_obj = {}
     if attachment:
         lport_obj["vif_uuid"] = attachment
@@ -466,7 +516,7 @@ def plug_interface(clusters, lswitch_id, port, type, attachment=None):
     lport_obj["type"] = type
     try:
         resp_obj = do_single_request("PUT", uri, json.dumps(lport_obj),
-                                     cluster=dest_cluster)
+                                     cluster=cluster)
     except NvpApiClient.ResourceNotFound as e:
         LOG.error(_("Port or Network not found, Error: %s"), str(e))
         raise exception.PortNotFound(port_id=port, net_id=lswitch_id)
diff --git a/quantum/tests/unit/nicira/etc/fake_get_lswitch.json b/quantum/tests/unit/nicira/etc/fake_get_lswitch.json
index e53a15e6f1..58b132b307 100644
--- a/quantum/tests/unit/nicira/etc/fake_get_lswitch.json
+++ b/quantum/tests/unit/nicira/etc/fake_get_lswitch.json
@@ -4,7 +4,9 @@
  "_relations": {"LogicalSwitchStatus":
      {"fabric_status": true,
       "type": "LogicalSwitchStatus",
+      "lport_count": %(lport_count)d,
       "_href": "/ws.v1/lswitch/%(uuid)s/status",
       "_schema": "/ws.v1/schema/LogicalSwitchStatus"}},
  "type": "LogicalSwitchConfig",
+ "tags": %(tags_json)s,
  "uuid": "%(uuid)s"}
diff --git a/quantum/tests/unit/nicira/fake_nvpapiclient.py b/quantum/tests/unit/nicira/fake_nvpapiclient.py
index 962949639f..b538ec1406 100644
--- a/quantum/tests/unit/nicira/fake_nvpapiclient.py
+++ b/quantum/tests/unit/nicira/fake_nvpapiclient.py
@@ -77,6 +77,7 @@ class FakeClient:
         zone_uuid = fake_lswitch['transport_zones'][0]['zone_uuid']
         fake_lswitch['zone_uuid'] = zone_uuid
         fake_lswitch['tenant_id'] = self._get_tag(fake_lswitch, 'os_tid')
+        fake_lswitch['lport_count'] = 0
         return fake_lswitch
 
     def _add_lport(self, body, ls_uuid):
@@ -92,6 +93,7 @@ class FakeClient:
         self._fake_lport_dict[fake_lport['uuid']] = fake_lport
 
         fake_lswitch = self._fake_lswitch_dict[ls_uuid]
+        fake_lswitch['lport_count'] += 1
         fake_lport_status = fake_lport.copy()
         fake_lport_status['ls_tenant_id'] = fake_lswitch['tenant_id']
         fake_lport_status['ls_uuid'] = fake_lswitch['uuid']
@@ -115,7 +117,6 @@ class FakeClient:
     def _list(self, resource_type, response_file,
               switch_uuid=None, query=None):
         (tag_filter, attr_filter) = self._get_filters(query)
-
         with open("%s/%s" % (self.fake_files_path, response_file)) as f:
             response_template = f.read()
             res_dict = getattr(self, '_fake_%s_dict' % resource_type)
@@ -143,7 +144,9 @@ class FakeClient:
                         res_dict[res_uuid].get('ls_uuid') == switch_uuid):
                     return True
                 return False
-
+            for item in res_dict.itervalues():
+                if 'tags' in item:
+                    item['tags_json'] = json.dumps(item['tags'])
             items = [json.loads(response_template % res_dict[res_uuid])
                      for res_uuid in res_dict
                      if (_lswitch_match(res_uuid) and
@@ -159,6 +162,10 @@ class FakeClient:
         with open("%s/%s" % (self.fake_files_path, response_file)) as f:
             response_template = f.read()
             res_dict = getattr(self, '_fake_%s_dict' % resource_type)
+            for item in res_dict.itervalues():
+                if 'tags' in item:
+                    item['tags_json'] = json.dumps(item['tags'])
+
             items = [json.loads(response_template % res_dict[res_uuid])
                      for res_uuid in res_dict if res_uuid == target_uuid]
             if items:
diff --git a/quantum/tests/unit/nicira/test_nicira_plugin.py b/quantum/tests/unit/nicira/test_nicira_plugin.py
index c6e11881b2..72bb541d69 100644
--- a/quantum/tests/unit/nicira/test_nicira_plugin.py
+++ b/quantum/tests/unit/nicira/test_nicira_plugin.py
@@ -13,14 +13,22 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
 import os
 
 import mock
+import webob.exc
 
 import quantum.common.test_lib as test_lib
+from quantum import context
+from quantum.extensions import providernet as pnet
+from quantum import manager
+from quantum.openstack.common import cfg
+from quantum.plugins.nicira.nicira_nvp_plugin import nvplib
 from quantum.tests.unit.nicira import fake_nvpapiclient
 import quantum.tests.unit.test_db_plugin as test_plugin
 
+LOG = logging.getLogger(__name__)
 NICIRA_PKG_PATH = 'quantum.plugins.nicira.nicira_nvp_plugin'
 
 
@@ -28,6 +36,26 @@ class NiciraPluginV2TestCase(test_plugin.QuantumDbPluginV2TestCase):
 
     _plugin_name = ('%s.QuantumPlugin.NvpPluginV2' % NICIRA_PKG_PATH)
 
+    def _create_network(self, fmt, name, admin_status_up,
+                        arg_list=None, providernet_args=None, **kwargs):
+        data = {'network': {'name': name,
+                            'admin_state_up': admin_status_up,
+                            'tenant_id': self._tenant_id}}
+        attributes = kwargs
+        if providernet_args:
+            attributes.update(providernet_args)
+        for arg in (('admin_state_up', 'tenant_id', 'shared') +
+                    (arg_list or ())):
+            # Arg must be present and not empty
+            if arg in kwargs and kwargs[arg]:
+                data['network'][arg] = kwargs[arg]
+        network_req = self.new_create_request('networks', data, fmt)
+        if (kwargs.get('set_context') and 'tenant_id' in kwargs):
+            # create a specific auth context for this request
+            network_req.environ['quantum.context'] = context.Context(
+                '', kwargs['tenant_id'])
+        return network_req.get_response(self.api)
+
     def setUp(self):
         etc_path = os.path.join(os.path.dirname(__file__), 'etc')
         test_lib.test_config['config_files'] = [os.path.join(etc_path,
@@ -61,9 +89,66 @@ class TestNiciraV2HTTPResponse(test_plugin.TestV2HTTPResponse,
 
 
 class TestNiciraPortsV2(test_plugin.TestPortsV2, NiciraPluginV2TestCase):
-    pass
+
+    def test_exhaust_ports_overlay_network(self):
+        cfg.CONF.set_override('max_lp_per_overlay_ls', 1, group='NVP')
+        with self.network(name='testnet',
+                          arg_list=(pnet.NETWORK_TYPE,
+                                    pnet.PHYSICAL_NETWORK,
+                                    pnet.SEGMENTATION_ID)) as net:
+            with self.subnet(network=net) as sub:
+                with self.port(subnet=sub):
+                    # creating another port should see an exception
+                    self._create_port('json', net['network']['id'], 400)
+
+    def test_exhaust_ports_bridged_network(self):
+        cfg.CONF.set_override('max_lp_per_bridged_ls', 1, group="NVP")
+        providernet_args = {pnet.NETWORK_TYPE: 'flat',
+                            pnet.PHYSICAL_NETWORK: 'tzuuid'}
+        with self.network(name='testnet',
+                          providernet_args=providernet_args,
+                          arg_list=(pnet.NETWORK_TYPE,
+                                    pnet.PHYSICAL_NETWORK,
+                                    pnet.SEGMENTATION_ID)) as net:
+            with self.subnet(network=net) as sub:
+                with self.port(subnet=sub):
+                    with self.port(subnet=sub):
+                        plugin = manager.QuantumManager.get_plugin()
+                        ls = nvplib.get_lswitches(plugin.default_cluster,
+                                                  net['network']['id'])
+                        self.assertEqual(len(ls), 2)
 
 
 class TestNiciraNetworksV2(test_plugin.TestNetworksV2,
                            NiciraPluginV2TestCase):
-    pass
+
+    def _test_create_bridge_network(self, vlan_id=None):
+        net_type = vlan_id and 'vlan' or 'flat'
+        name = 'bridge_net'
+        keys = [('subnets', []), ('name', name), ('admin_state_up', True),
+                ('status', 'ACTIVE'), ('shared', False),
+                (pnet.NETWORK_TYPE, net_type),
+                (pnet.PHYSICAL_NETWORK, 'tzuuid'),
+                (pnet.SEGMENTATION_ID, vlan_id)]
+        providernet_args = {pnet.NETWORK_TYPE: net_type,
+                            pnet.PHYSICAL_NETWORK: 'tzuuid'}
+        if vlan_id:
+            providernet_args[pnet.SEGMENTATION_ID] = vlan_id
+        with self.network(name=name,
+                          providernet_args=providernet_args,
+                          arg_list=(pnet.NETWORK_TYPE,
+                                    pnet.PHYSICAL_NETWORK,
+                                    pnet.SEGMENTATION_ID)) as net:
+            for k, v in keys:
+                self.assertEquals(net['network'][k], v)
+
+    def test_create_bridge_network(self):
+        self._test_create_bridge_network()
+
+    def test_create_bridge_vlan_network(self):
+        self._test_create_bridge_network(vlan_id=123)
+
+    def test_create_bridge_vlan_network_outofrange_returns_400(self):
+        with self.assertRaises(webob.exc.HTTPClientError) as ctx_manager:
+            self._test_create_bridge_network(vlan_id=5000)
+        self.assertEquals(ctx_manager.exception.code, 400)