diff --git a/config/interface.py b/config/interface.py
index d055ee3..86c3b1e 100644
--- a/config/interface.py
+++ b/config/interface.py
@@ -63,6 +63,22 @@ def get_parent_by_name(yaml, ifname):
     return None,None
 
 
+def get_by_lcp_name(yaml, lcpname):
+    """ Returns the interface or sub-interface by a given lcp name, or None,None if it does not exist """
+    if not 'interfaces' in yaml:
+        return None,None
+    for ifname, iface in yaml['interfaces'].items():
+        if 'lcp' in iface and iface['lcp'] == lcpname:
+            return ifname, iface
+        if not 'sub-interfaces' in iface:
+            continue
+        for subid, sub_iface in yaml['interfaces'][ifname]['sub-interfaces'].items():
+            sub_ifname = "%s.%d" % (ifname, subid)
+            if 'lcp' in sub_iface and sub_iface['lcp'] == lcpname:
+                return sub_ifname, sub_iface
+    return None,None
+
+
 def get_by_name(yaml, ifname):
     """ Returns the interface or sub-interface by a given name, or None,None if it does not exist """
     if '.' in ifname:
@@ -217,6 +233,7 @@ def get_encapsulation(yaml, ifname):
     exact_match = False
     if not 'encapsulation' in iface:
         dot1q = int(subid)
+        exact_match = True
     else:
         if 'dot1q' in iface['encapsulation']:
             dot1q = iface['encapsulation']['dot1q']
diff --git a/config/test_interface.py b/config/test_interface.py
index 5b91125..acf1f40 100644
--- a/config/test_interface.py
+++ b/config/test_interface.py
@@ -136,6 +136,16 @@ class TestInterfaceMethods(unittest.TestCase):
         self.assertTrue(interface.is_l3(self.cfg, "GigabitEthernet1/0/0"))
         self.assertFalse(interface.is_l3(self.cfg, "GigabitEthernet3/0/0"))
 
+    def test_get_by_lcp_name(self):
+        ifname, iface = interface.get_by_lcp_name(self.cfg, "notexist")
+        self.assertIsNone(ifname)
+        self.assertIsNone(iface)
+
+        ifname, iface = interface.get_by_lcp_name(self.cfg, "e1.100.100")
+        self.assertEqual(ifname, "GigabitEthernet1/0/1.102")
+        ifname, iface = interface.get_by_lcp_name(self.cfg, "e2")
+        self.assertEqual(ifname, "GigabitEthernet2/0/0")
+
     def test_get_by_name(self):
         ifname, iface = interface.get_by_name(self.cfg, "GigabitEthernet1/0/1.201")
         self.assertEqual(ifname, "GigabitEthernet1/0/1.201")
diff --git a/unittest/test_interface.yaml b/unittest/test_interface.yaml
index 72542b7..0af3681 100644
--- a/unittest/test_interface.yaml
+++ b/unittest/test_interface.yaml
@@ -17,6 +17,7 @@ interfaces:
         description: "This sub-int is has the same encap as 102"
         encapsulation:
           dot1q: 102
+          exact-match: True
 
   GigabitEthernet1/0/1:
     mtu: 9216
diff --git a/unittest/yaml/error-subinterface1.yaml b/unittest/yaml/error-subinterface1.yaml
index 4335ef0..750b719 100644
--- a/unittest/yaml/error-subinterface1.yaml
+++ b/unittest/yaml/error-subinterface1.yaml
@@ -3,7 +3,7 @@ test:
   errors:
     expected:
      - "sub-interface .*.100 does not have unique encapsulation"
-     - "sub-interface .*.101 does not have unique encapsulation"
+     - "sub-interface .*.102 does not have unique encapsulation"
     count: 2
 ---
 interfaces:
@@ -12,7 +12,11 @@ interfaces:
       100:
         description: "VLAN 100"
       101:
-        description: "Another VLAN 100"
+        description: "Another VLAN 100, but without exact-match"
         encapsulation:
           dot1q: 100
-
+      102:
+        description: "Another VLAN 100, but without exact-match"
+        encapsulation:
+          dot1q: 100
+          exact-match: True