diff --git a/xos/synchronizer/models/fabric-crossconnect.xproto b/xos/synchronizer/models/fabric-crossconnect.xproto
old mode 100644
new mode 100755
index 4a7e8dc..989ebc1
--- a/xos/synchronizer/models/fabric-crossconnect.xproto
+++ b/xos/synchronizer/models/fabric-crossconnect.xproto
@@ -1,5 +1,6 @@
 option name = "fabric-crossconnect";
 option app_label = "fabric-crossconnect";
+option legacy = "True";
 
 message FabricCrossconnectService (Service){
     option verbose_name = "Fabric Crossconnect Service";
@@ -12,6 +13,6 @@
 }
 
 message BNGPortMapping (XOSBase) {
-    required int32 s_tag = 1 [help_text = "S Tag", null = False, db_index = False, blank = False, unique=True, tosca_key=True];
+    required string s_tag = 1 [help_text = "Single s-tag, range of s-tags, or ANY", null = False, db_index = False, blank = False, unique=True, tosca_key=True];
     required int32 switch_port = 2 [help_text = "Port Number", null = False, db_index = False, blank = False];
 }
diff --git a/xos/synchronizer/models/models.py b/xos/synchronizer/models/models.py
new file mode 100755
index 0000000..75ebe1d
--- /dev/null
+++ b/xos/synchronizer/models/models.py
@@ -0,0 +1,52 @@
+# Copyright 2017-present Open Networking Foundation
+#
+# 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 xos.exceptions import XOSValidationError
+
+from models_decl import FabricCrossconnectService_decl, FabricCrossconnectServiceInstance_decl, BNGPortMapping_decl
+
+class FabricCrossconnectService(FabricCrossconnectService_decl):
+    class Meta:
+        proxy = True
+
+class FabricCrossconnectServiceInstance(FabricCrossconnectServiceInstance_decl):
+   class Meta:
+        proxy = True
+
+class BNGPortMapping(BNGPortMapping_decl):
+    class Meta:
+        proxy = True
+
+    def validate_range(self, pattern):
+        for this_range in pattern.split(","):
+            this_range = this_range.strip()
+            if "-" in this_range:
+                (first, last) = this_range.split("-")
+                try:
+                    int(first.strip())
+                    int(last.strip())
+                except ValueError:
+                    raise XOSValidationError("Malformed range %s" % pattern)
+            elif this_range.lower()=="any":
+                pass
+            else:
+                try:
+                    int(this_range)
+                except ValueError:
+                    raise XOSValidationError("Malformed range %s" % pattern)
+
+    def save(self, *args, **kwargs):
+        self.validate_range(self.s_tag)
+        super(BNGPortMapping, self).save(*args, **kwargs)
+
diff --git a/xos/synchronizer/models/test_models.py b/xos/synchronizer/models/test_models.py
new file mode 100755
index 0000000..3d42609
--- /dev/null
+++ b/xos/synchronizer/models/test_models.py
@@ -0,0 +1,124 @@
+# Copyright 2017-present Open Networking Foundation
+#
+# 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 unittest
+import os, sys
+from mock import patch, Mock, MagicMock
+
+test_path=os.path.abspath(os.path.dirname(os.path.realpath(__file__)))
+service_dir=os.path.join(test_path, "../../../..")
+xos_dir=os.path.join(test_path, "../../..")
+if not os.path.exists(os.path.join(test_path, "new_base")):
+    xos_dir=os.path.join(test_path, "../../../../../../orchestration/xos/xos")
+    services_dir=os.path.join(xos_dir, "../../xos_services")
+
+# mocking XOS exception, as they're based in Django
+class Exceptions:
+    XOSValidationError = Exception
+    XOSProgrammingError = Exception
+    XOSPermissionDenied = Exception
+
+class XOS:
+    exceptions = Exceptions
+
+class TestFabricCrossconnectModels(unittest.TestCase):
+    def setUp(self):
+
+        self.sys_path_save = sys.path
+        sys.path.append(xos_dir)
+
+        self.xos = XOS
+
+        self.models_decl = Mock()
+        self.models_decl.BNGPortMapping_decl = MagicMock
+        self.models_decl.BNGPortMapping_decl.save = Mock()
+        self.models_decl.BNGPortMapping_decl.objects = Mock()
+        self.models_decl.BNGPortMapping_decl.objects.filter.return_value = []
+
+
+        modules = {
+            'xos.exceptions': self.xos.exceptions,
+            'models_decl': self.models_decl
+        }
+
+        self.module_patcher = patch.dict('sys.modules', modules)
+        self.module_patcher.start()
+
+        self.volt = Mock()
+
+        from models import BNGPortMapping
+
+        self.BNGPortMapping = BNGPortMapping()
+
+    def tearDown(self):
+        sys.path = self.sys_path_save
+
+    def test_validate_range_single(self):
+        bpm = self.BNGPortMapping()
+        bpm.validate_range("123")
+
+    def test_validate_range_commas(self):
+        bpm = self.BNGPortMapping()
+        bpm.validate_range("123, 456")
+
+    def test_validate_range_ANY(self):
+        bpm = self.BNGPortMapping()
+        bpm.validate_range("ANY")
+        bpm.validate_range("any")
+
+    def test_validate_range_dash(self):
+        bpm = self.BNGPortMapping()
+        bpm.validate_range("123-456")
+
+    def test_validate_dash_commas(self):
+        bpm = self.BNGPortMapping()
+        bpm.validate_range("123-456, 789 - 1000")
+
+    def test_validate_range_empty(self):
+        bpm = self.BNGPortMapping()
+        with self.assertRaises(Exception) as e:
+            bpm.validate_range("")
+
+        self.assertEqual(e.exception.message, 'Malformed range ')
+
+    def test_validate_range_none(self):
+        bpm = self.BNGPortMapping()
+        with self.assertRaises(Exception) as e:
+            bpm.validate_range("")
+
+        self.assertEqual(e.exception.message, 'Malformed range ')
+
+    def test_validate_range_all(self):
+        bpm = self.BNGPortMapping()
+        with self.assertRaises(Exception) as e:
+            bpm.validate_range("badstring")
+
+        self.assertEqual(e.exception.message, 'Malformed range badstring')
+
+    def test_validate_half_range(self):
+        bpm = self.BNGPortMapping()
+        with self.assertRaises(Exception) as e:
+            bpm.validate_range("123-")
+
+        self.assertEqual(e.exception.message, 'Malformed range 123-')
+
+    def test_validate_half_comma(self):
+        bpm = self.BNGPortMapping()
+        with self.assertRaises(Exception) as e:
+            bpm.validate_range("123,")
+
+        self.assertEqual(e.exception.message, 'Malformed range 123,')
+
+if __name__ == '__main__':
+    unittest.main()