diff --git a/config/bridgedomain.py b/config/bridgedomain.py
index b860257..a85e0ac 100644
--- a/config/bridgedomain.py
+++ b/config/bridgedomain.py
@@ -99,6 +99,10 @@ def validate_bridgedomains(yaml):
         if instance == 0:
             msgs.append("bridgedomain %s is reserved" % ifname)
             result = False
+        elif instance > 16777215:
+            msgs.append("bridgedomain %s has instance %d which is too large" % (ifname, instance))
+            result = False
+
         if 'bvi' in iface:
             bviname = iface['bvi']
             if (None,None) == loopback.get_by_name(yaml, bviname):
diff --git a/config/loopback.py b/config/loopback.py
index 09341d2..09fe243 100644
--- a/config/loopback.py
+++ b/config/loopback.py
@@ -61,8 +61,9 @@ def validate_loopbacks(yaml):
 
     for ifname, iface in yaml['loopbacks'].items():
         logger.debug("loopback %s" % iface)
-        if 'addresses' in iface and not 'lcp' in iface:
-            msgs.append("loopback %s has an address but no LCP" % ifname)
+        instance = int(ifname[4:])
+        if instance > 4095:
+            msgs.append("loopback %s has instance %d which is too large" % (ifname, instance))
             result = False
         if 'lcp' in iface and not lcp.is_unique(yaml, iface['lcp']):
             msgs.append("loopback %s does not have a unique LCP name %s" % (ifname, iface['lcp']))
diff --git a/unittest/yaml/error-bridgedomain9.yaml b/unittest/yaml/error-bridgedomain9.yaml
new file mode 100644
index 0000000..683bd5e
--- /dev/null
+++ b/unittest/yaml/error-bridgedomain9.yaml
@@ -0,0 +1,15 @@
+test:
+  description: "BridgeDomain instance must be between 1 and 16M"
+  errors:
+    expected:
+     - "bridgedomain bd0 is reserved"
+     - "bridgedomain .* has instance .* which is too large"
+    count: 2
+---
+bridgedomains:
+  bd0:
+    description: "Reserved in VPP"
+  bd16777215:
+    description: "Cool."
+  bd16777216:
+    description: "Not cool."
diff --git a/unittest/yaml/error-loopback1.yaml b/unittest/yaml/error-loopback1.yaml
index e427da1..c70b88e 100644
--- a/unittest/yaml/error-loopback1.yaml
+++ b/unittest/yaml/error-loopback1.yaml
@@ -1,12 +1,12 @@
 test:
-  description: "Cannot give an IP address to a loopback without LCP"
+  description: "Loopback instances must be between 0 and 4095"
   errors:
     expected:
-     - "loopback .* has an address but no LCP"
+     - "loopback .* has instance 4096 which is too large"
     count: 1
 ---
 loopbacks:
-  loop10:
-    description: "Loopback instance loop10, with address, but no LCP"
-    mtu: 9216
-    addresses: [ 192.0.2.1/29 ]
+  loop4095:
+    description: "Cool."
+  loop4096:
+    description: "Not cool."