diff --git a/models/openconfig/src/main/yang/types/openconfig-yang-types.yang b/models/openconfig/src/main/yang/types/openconfig-yang-types.yang
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+++ b/models/openconfig/src/main/yang/types/openconfig-yang-types.yang
@@ -0,0 +1,156 @@
+module openconfig-yang-types {
+
+  yang-version "1";
+  namespace "http://openconfig.net/yang/types/yang";
+  prefix "oc-yang";
+
+  import openconfig-extensions { prefix "oc-ext"; }
+
+  organization
+    "OpenConfig working group";
+
+  contact
+    "OpenConfig working group
+    www.openconfig.net";
+
+  description
+    "This module contains a set of extension types to the
+    YANG builtin types that are used across multiple
+    OpenConfig models.
+
+    Portions of this code were derived from IETF RFC 6021.
+    Please reproduce this note if possible.
+
+    IETF code is subject to the following copyright and license:
+    Copyright (c) IETF Trust and the persons identified as authors of
+    the code.
+    All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, is permitted pursuant to, and subject to the license
+    terms contained in, the Simplified BSD License set forth in
+    Section 4.c of the IETF Trust's Legal Provisions Relating
+    to IETF Documents (http://trustee.ietf.org/license-info).";
+
+  oc-ext:openconfig-version "0.1.2";
+
+  revision 2017-07-30 {
+    description
+      "Fixed unprintable character";
+    reference "0.1.2";
+  }
+
+  revision 2017-04-03 {
+    description
+      "Update copyright notice.";
+    reference "0.1.1";
+  }
+
+  revision 2017-01-26 {
+    description
+      "Initial module for inet types";
+    reference "0.1.0";
+  }
+
+  typedef dotted-quad {
+    type string {
+      pattern '^(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|'       +
+              '25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4]' +
+              '[0-9]|25[0-5])$';
+    }
+    description
+      "An unsigned 32-bit integer expressed as a dotted quad. The
+      format is four octets written as decimal numbers separated
+      with a period character.";
+  }
+
+  typedef hex-string {
+    type string {
+      pattern '^[0-9a-fA-F]*$';
+    }
+    description
+      "A string consisting of a hexadecimal characters.";
+  }
+
+  typedef counter32 {
+    type uint32;
+    description
+
+      "A 32-bit counter. A counter value is a monotonically increasing
+      value which is used to express a count of a number of
+      occurrences of a particular event or entity. When the counter
+      reaches its maximum value, in this case 2^32-1, it wraps to 0.
+
+      Discontinuities in the counter are generally triggered only when
+      the counter is reset to zero.";
+  }
+
+  typedef counter64 {
+    type uint64;
+    description
+
+      "A 64-bit counter. A counter value is a monotonically increasing
+      value which is used to express a count of a number of
+      occurrences of a particular event or entity. When a counter64
+      reaches its maximum value, 2^64-1, it loops to zero.
+      Discontinuities in a counter are generally triggered only when
+      the counter is reset to zero, through operator or system
+      intervention.";
+  }
+
+  typedef date-and-time {
+    type string {
+      pattern
+        '^[0-9]{4}\-[0-9]{2}\-[0-9]{2}T[0-9]{2}:[0-9]{2}:[0-9]{2}' +
+        '(\.[0-9]+)?Z[+-][0-9]{2}:[0-9]{2}$';
+    }
+    description
+      "A date and time, expressed in the format described in RFC3339.
+      That is to say:
+
+      YYYY-MM-DDTHH:MM:SSZ+-hh:mm
+
+      where YYYY is the year, MM is the month expressed as a two-digit
+      month (zero padding if required), DD is the day of the month,
+      expressed as a two digit value. T is the literal character 'T',
+      HH is the hour of the day expressed as a two digit number, using
+      the 24-hour clock, MM is the minute of the hour expressed as a
+      two digit number. Z is the literal character 'Z', followed by a
+      timezone offset expressed in hours (hh) and minutes (mm), both
+      expressed as two digit numbers. The time offset is specified as
+      a positive or negative offset to UTC using the '+' or '-'
+      character preceding the offset.
+
+      Optionally, fractional seconds can be expressed after the minute
+      of the hour as a decimal number of unspecified precision
+      reflecting fractions of a second.";
+    reference
+      "RFC3339 - Date and Time on the Internet: Timestamps";
+  }
+
+  typedef gauge64 {
+    type uint64;
+    description
+      "A gauge value may increase or decrease - and reflects a value
+      at a particular point in time. If the value of the variable
+      being modeled using the gauge exceeds its maximum - 2^64-1 in
+      this case - the gauge is set to its maximum value.";
+  }
+
+  typedef phys-address {
+    type string {
+      pattern '^([0-9a-fA-F]{2}(:[0-9a-fA-F]{2})*)?$';
+    }
+    description
+      "A physical layer address, expressed as a series of pairs of
+      hexadecimal digits.";
+  }
+
+  typedef mac-address {
+    type string {
+      pattern '^[0-9a-fA-F]{2}(:[0-9a-fA-F]{2}){5}$';
+    }
+    description
+      "An IEEE 802 MAC address";
+  }
+}