diff --git a/models/ietf/BUCK b/models/ietf/BUCK
new file mode 100644
index 0000000..6cc9d15
--- /dev/null
+++ b/models/ietf/BUCK
@@ -0,0 +1,7 @@
+
+yang_model (
+  app_name = 'org.onosproject.models.ietf',
+  title = 'IETF YANG Models',
+  custom_registrator = False,
+  deps = [ '//lib:CORE_DEPS' ]
+)
diff --git a/models/ietf/pom.xml b/models/ietf/pom.xml
new file mode 100644
index 0000000..db77247
--- /dev/null
+++ b/models/ietf/pom.xml
@@ -0,0 +1,170 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ Copyright 2018-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.
+  -->
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>org.onosproject</groupId>
+        <artifactId>onos-models</artifactId>
+        <version>1.14.0-SNAPSHOT</version>
+        <relativePath>../pom.xml</relativePath>
+    </parent>
+
+    <artifactId>onos-models-ietf</artifactId>
+    <packaging>bundle</packaging>
+
+    <properties>
+        <onos.app.name>org.onosproject.models.ietf</onos.app.name>
+    </properties>
+
+    <dependencies>
+
+        <dependency>
+            <groupId>org.onosproject</groupId>
+            <artifactId>onos-yang-model</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.onosproject</groupId>
+            <artifactId>onos-apps-yang</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+
+    </dependencies>
+
+    <build>
+        <plugins>
+
+            <plugin>
+                <groupId>org.apache.felix</groupId>
+                <artifactId>maven-bundle-plugin</artifactId>
+                <extensions>true</extensions>
+                <configuration>
+                    <instructions combine.children="append">
+                        <Include-Resource>yang/resources/YangMetaData.ser=target/classes/yang/resources/YangMetaData.ser</Include-Resource>
+                    </instructions>
+                </configuration>
+            </plugin>
+
+            <plugin>
+                <groupId>org.onosproject</groupId>
+                <artifactId>onos-yang-compiler-maven-plugin</artifactId>
+            </plugin>
+
+            <plugin>
+                <groupId>org.onosproject</groupId>
+                <artifactId>onos-maven-plugin</artifactId>
+            </plugin>
+
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>build-helper-maven-plugin</artifactId>
+                <version>3.0.0</version>
+                <executions>
+                  <execution>
+                    <id>add-source</id>
+                    <phase>generate-sources</phase>
+                    <goals>
+                      <goal>add-source</goal>
+                    </goals>
+                    <configuration>
+                      <sources>
+                        <source>${project.build.directory}/generated-sources</source>
+                      </sources>
+                    </configuration>
+                  </execution>
+                </executions>
+            </plugin>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-clean-plugin</artifactId>
+                <version>3.0.0</version>
+                <executions>
+                    <execution>
+                        <id>onos-yang-plugin-workaround</id>
+                        <!-- yang plugin cannot handle non-clean compilation -->
+                        <phase>initialize</phase>
+                        <goals>
+                            <goal>clean</goal>
+                        </goals>
+                        <configuration>
+                            <excludeDefaultDirectories>true</excludeDefaultDirectories>
+                            <filesets>
+                                <fileset>
+                                    <directory>target/generated-sources</directory>
+                                </fileset>
+                            </filesets>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+
+            <!-- FIXME: YANG tool generates problematic code -->
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <compilerArgs>
+                      <arg>-XepDisableAllChecks</arg>
+                      <arg>-Xep:BetaApi:OFF</arg>
+                    </compilerArgs>
+                </configuration>
+            </plugin>
+
+        </plugins>
+
+        <pluginManagement>
+            <plugins>
+                <!--This plugin's configuration is used to store Eclipse m2e settings only. It has no influence on the Maven build itself.-->
+                <plugin>
+                    <groupId>org.eclipse.m2e</groupId>
+                    <artifactId>lifecycle-mapping</artifactId>
+                    <version>1.0.0</version>
+                    <configuration>
+                        <lifecycleMappingMetadata>
+                            <pluginExecutions>
+                                <pluginExecution>
+                                    <pluginExecutionFilter>
+                                        <groupId>
+                                            org.apache.maven.plugins
+                                        </groupId>
+                                        <artifactId>
+                                            maven-clean-plugin
+                                        </artifactId>
+                                        <versionRange>
+                                            [3.0.0,)
+                                        </versionRange>
+                                        <goals>
+                                            <goal>clean</goal>
+                                        </goals>
+                                    </pluginExecutionFilter>
+                                    <action>
+                                        <ignore></ignore>
+                                    </action>
+                                </pluginExecution>
+                            </pluginExecutions>
+                        </lifecycleMappingMetadata>
+                    </configuration>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+
+</project>
diff --git a/models/ietf/src/main/yang/ietf-inet-types@2013-07-15.yang b/models/ietf/src/main/yang/ietf-inet-types@2013-07-15.yang
new file mode 100644
index 0000000..2b7ed38
--- /dev/null
+++ b/models/ietf/src/main/yang/ietf-inet-types@2013-07-15.yang
@@ -0,0 +1,454 @@
+  module ietf-inet-types {
+
+    yang-version 1;
+
+    namespace
+      "urn:ietf:params:xml:ns:yang:ietf-inet-types";
+
+    prefix inet;
+
+    organization
+      "IETF NETMOD (NETCONF Data Modeling Language) Working Group";
+
+    contact
+      "WG Web:   <http://tools.ietf.org/wg/netmod/>
+    WG List:  <mailto:netmod@ietf.org>
+
+    WG Chair: David Kessens
+              <mailto:david.kessens@nsn.com>
+
+    WG Chair: Juergen Schoenwaelder
+              <mailto:j.schoenwaelder@jacobs-university.de>
+
+    Editor:   Juergen Schoenwaelder
+              <mailto:j.schoenwaelder@jacobs-university.de>";
+
+    description
+      "This module contains a collection of generally useful derived
+    YANG data types for Internet addresses and related things.
+
+    Copyright (c) 2013 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).
+
+    This version of this YANG module is part of RFC 6991; see
+    the RFC itself for full legal notices.";
+
+    revision "2013-07-15" {
+      description
+        "This revision adds the following new data types:
+      - ip-address-no-zone
+      - ipv4-address-no-zone
+      - ipv6-address-no-zone";
+      reference
+        "RFC 6991: Common YANG Data Types";
+
+    }
+
+    revision "2010-09-24" {
+      description "Initial revision.";
+      reference
+        "RFC 6021: Common YANG Data Types";
+
+    }
+
+
+    typedef ip-version {
+      type enumeration {
+        enum "unknown" {
+          value 0;
+          description
+            "An unknown or unspecified version of the Internet
+          protocol.";
+        }
+        enum "ipv4" {
+          value 1;
+          description
+            "The IPv4 protocol as defined in RFC 791.";
+        }
+        enum "ipv6" {
+          value 2;
+          description
+            "The IPv6 protocol as defined in RFC 2460.";
+        }
+      }
+      description
+        "This value represents the version of the IP protocol.
+
+      In the value set and its semantics, this type is equivalent
+      to the InetVersion textual convention of the SMIv2.";
+      reference
+        "RFC  791: Internet Protocol
+         RFC 2460: Internet Protocol, Version 6 (IPv6) Specification
+         RFC 4001: Textual Conventions for Internet Network Addresses";
+
+    }
+
+    typedef dscp {
+      type uint8 {
+        range "0..63";
+      }
+      description
+        "The dscp type represents a Differentiated Services Code Point
+      that may be used for marking packets in a traffic stream.
+      In the value set and its semantics, this type is equivalent
+      to the Dscp textual convention of the SMIv2.";
+      reference
+        "RFC 3289: Management Information Base for the Differentiated
+        	  Services Architecture
+         RFC 2474: Definition of the Differentiated Services Field
+        	  (DS Field) in the IPv4 and IPv6 Headers
+         RFC 2780: IANA Allocation Guidelines For Values In
+        	  the Internet Protocol and Related Headers";
+
+    }
+
+    typedef ipv6-flow-label {
+      type uint32 {
+        range "0..1048575";
+      }
+      description
+        "The ipv6-flow-label type represents the flow identifier or Flow
+      Label in an IPv6 packet header that may be used to
+      discriminate traffic flows.
+
+      In the value set and its semantics, this type is equivalent
+      to the IPv6FlowLabel textual convention of the SMIv2.";
+      reference
+        "RFC 3595: Textual Conventions for IPv6 Flow Label
+         RFC 2460: Internet Protocol, Version 6 (IPv6) Specification";
+
+    }
+
+    typedef port-number {
+      type uint16 {
+        range "0..65535";
+      }
+      description
+        "The port-number type represents a 16-bit port number of an
+      Internet transport-layer protocol such as UDP, TCP, DCCP, or
+      SCTP.  Port numbers are assigned by IANA.  A current list of
+      all assignments is available from <http://www.iana.org/>.
+
+      Note that the port number value zero is reserved by IANA.  In
+      situations where the value zero does not make sense, it can
+      be excluded by subtyping the port-number type.
+      In the value set and its semantics, this type is equivalent
+      to the InetPortNumber textual convention of the SMIv2.";
+      reference
+        "RFC  768: User Datagram Protocol
+         RFC  793: Transmission Control Protocol
+         RFC 4960: Stream Control Transmission Protocol
+         RFC 4340: Datagram Congestion Control Protocol (DCCP)
+         RFC 4001: Textual Conventions for Internet Network Addresses";
+
+    }
+
+    typedef as-number {
+      type uint32;
+      description
+        "The as-number type represents autonomous system numbers
+      which identify an Autonomous System (AS).  An AS is a set
+      of routers under a single technical administration, using
+      an interior gateway protocol and common metrics to route
+      packets within the AS, and using an exterior gateway
+      protocol to route packets to other ASes.  IANA maintains
+      the AS number space and has delegated large parts to the
+      regional registries.
+
+      Autonomous system numbers were originally limited to 16
+      bits.  BGP extensions have enlarged the autonomous system
+      number space to 32 bits.  This type therefore uses an uint32
+      base type without a range restriction in order to support
+      a larger autonomous system number space.
+
+      In the value set and its semantics, this type is equivalent
+      to the InetAutonomousSystemNumber textual convention of
+      the SMIv2.";
+      reference
+        "RFC 1930: Guidelines for creation, selection, and registration
+        	  of an Autonomous System (AS)
+         RFC 4271: A Border Gateway Protocol 4 (BGP-4)
+         RFC 4001: Textual Conventions for Internet Network Addresses
+         RFC 6793: BGP Support for Four-Octet Autonomous System (AS)
+        	  Number Space";
+
+    }
+
+    typedef ip-address {
+      type union {
+        type ipv4-address;
+        type ipv6-address;
+      }
+      description
+        "The ip-address type represents an IP address and is IP
+      version neutral.  The format of the textual representation
+      implies the IP version.  This type supports scoped addresses
+      by allowing zone identifiers in the address format.";
+      reference
+        "RFC 4007: IPv6 Scoped Address Architecture";
+
+    }
+
+    typedef ipv4-address {
+      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])(%[\p{N}\p{L}]+)?';
+      }
+      description
+        "The ipv4-address type represents an IPv4 address in
+       dotted-quad notation.  The IPv4 address may include a zone
+       index, separated by a % sign.
+
+       The zone index is used to disambiguate identical address
+       values.  For link-local addresses, the zone index will
+       typically be the interface index number or the name of an
+       interface.  If the zone index is not present, the default
+       zone of the device will be used.
+
+       The canonical format for the zone index is the numerical
+       format";
+    }
+
+    typedef ipv6-address {
+      type string {
+        pattern
+          '((:|[0-9a-fA-F]{0,4}):)([0-9a-fA-F]{0,4}:){0,5}((([0-9a-fA-F]{0,4}:)?(:|[0-9a-fA-F]{0,4}))|(((25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])))(%[\p{N}\p{L}]+)?';
+        pattern
+          '(([^:]+:){6}(([^:]+:[^:]+)|(.*\..*)))|((([^:]+:)*[^:]+)?::(([^:]+:)*[^:]+)?)(%.+)?';
+      }
+      description
+        "The ipv6-address type represents an IPv6 address in full,
+      mixed, shortened, and shortened-mixed notation.  The IPv6
+      address may include a zone index, separated by a % sign.
+
+      The zone index is used to disambiguate identical address
+      values.  For link-local addresses, the zone index will
+      typically be the interface index number or the name of an
+      interface.  If the zone index is not present, the default
+      zone of the device will be used.
+
+
+
+      The canonical format of IPv6 addresses uses the textual
+      representation defined in Section 4 of RFC 5952.  The
+      canonical format for the zone index is the numerical
+      format as described in Section 11.2 of RFC 4007.";
+      reference
+        "RFC 4291: IP Version 6 Addressing Architecture
+         RFC 4007: IPv6 Scoped Address Architecture
+         RFC 5952: A Recommendation for IPv6 Address Text
+        	  Representation";
+
+    }
+
+    typedef ip-address-no-zone {
+      type union {
+        type ipv4-address-no-zone;
+        type ipv6-address-no-zone;
+      }
+      description
+        "The ip-address-no-zone type represents an IP address and is
+      IP version neutral.  The format of the textual representation
+      implies the IP version.  This type does not support scoped
+      addresses since it does not allow zone identifiers in the
+      address format.";
+      reference
+        "RFC 4007: IPv6 Scoped Address Architecture";
+
+    }
+
+    typedef ipv4-address-no-zone {
+      type ipv4-address {
+        pattern '[0-9\.]*';
+      }
+      description
+        "An IPv4 address without a zone index.  This type, derived from
+       ipv4-address, may be used in situations where the zone is
+       known from the context and hence no zone index is needed.";
+    }
+
+    typedef ipv6-address-no-zone {
+      type ipv6-address {
+        pattern '[0-9a-fA-F:\.]*';
+      }
+      description
+        "An IPv6 address without a zone index.  This type, derived from
+       ipv6-address, may be used in situations where the zone is
+       known from the context and hence no zone index is needed.";
+      reference
+        "RFC 4291: IP Version 6 Addressing Architecture
+         RFC 4007: IPv6 Scoped Address Architecture
+         RFC 5952: A Recommendation for IPv6 Address Text
+        	  Representation";
+
+    }
+
+    typedef ip-prefix {
+      type union {
+        type ipv4-prefix;
+        type ipv6-prefix;
+      }
+      description
+        "The ip-prefix type represents an IP prefix and is IP
+      version neutral.  The format of the textual representations
+      implies the IP version.";
+    }
+
+    typedef ipv4-prefix {
+      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])/(([0-9])|([1-2][0-9])|(3[0-2]))';
+      }
+      description
+        "The ipv4-prefix type represents an IPv4 address prefix.
+      The prefix length is given by the number following the
+      slash character and must be less than or equal to 32.
+
+      A prefix length value of n corresponds to an IP address
+      mask that has n contiguous 1-bits from the most
+      significant bit (MSB) and all other bits set to 0.
+
+      The canonical format of an IPv4 prefix has all bits of
+      the IPv4 address set to zero that are not part of the
+      IPv4 prefix.";
+    }
+
+    typedef ipv6-prefix {
+      type string {
+        pattern
+          '((:|[0-9a-fA-F]{0,4}):)([0-9a-fA-F]{0,4}:){0,5}((([0-9a-fA-F]{0,4}:)?(:|[0-9a-fA-F]{0,4}))|(((25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])))(/(([0-9])|([0-9]{2})|(1[0-1][0-9])|(12[0-8])))';
+        pattern
+          '(([^:]+:){6}(([^:]+:[^:]+)|(.*\..*)))|((([^:]+:)*[^:]+)?::(([^:]+:)*[^:]+)?)(/.+)';
+      }
+      description
+        "The ipv6-prefix type represents an IPv6 address prefix.
+      The prefix length is given by the number following the
+      slash character and must be less than or equal to 128.
+
+      A prefix length value of n corresponds to an IP address
+      mask that has n contiguous 1-bits from the most
+      significant bit (MSB) and all other bits set to 0.
+
+      The IPv6 address should have all bits that do not belong
+      to the prefix set to zero.
+
+      The canonical format of an IPv6 prefix has all bits of
+      the IPv6 address set to zero that are not part of the
+      IPv6 prefix.  Furthermore, the IPv6 address is represented
+      as defined in Section 4 of RFC 5952.";
+      reference
+        "RFC 5952: A Recommendation for IPv6 Address Text
+        	  Representation";
+
+    }
+
+    typedef domain-name {
+      type string {
+        length "1..253";
+        pattern
+          '((([a-zA-Z0-9_]([a-zA-Z0-9\-_]){0,61})?[a-zA-Z0-9]\.)*([a-zA-Z0-9_]([a-zA-Z0-9\-_]){0,61})?[a-zA-Z0-9]\.?)|\.';
+      }
+      description
+        "The domain-name type represents a DNS domain name.  The
+      name SHOULD be fully qualified whenever possible.
+
+      Internet domain names are only loosely specified.  Section
+      3.5 of RFC 1034 recommends a syntax (modified in Section
+      2.1 of RFC 1123).  The pattern above is intended to allow
+      for current practice in domain name use, and some possible
+      future expansion.  It is designed to hold various types of
+      domain names, including names used for A or AAAA records
+      (host names) and other records, such as SRV records.  Note
+      that Internet host names have a stricter syntax (described
+      in RFC 952) than the DNS recommendations in RFCs 1034 and
+      1123, and that systems that want to store host names in
+      schema nodes using the domain-name type are recommended to
+      adhere to this stricter standard to ensure interoperability.
+
+      The encoding of DNS names in the DNS protocol is limited
+      to 255 characters.  Since the encoding consists of labels
+      prefixed by a length bytes and there is a trailing NULL
+      byte, only 253 characters can appear in the textual dotted
+      notation.
+
+      The description clause of schema nodes using the domain-name
+      type MUST describe when and how these names are resolved to
+      IP addresses.  Note that the resolution of a domain-name value
+      may require to query multiple DNS records (e.g., A for IPv4
+      and AAAA for IPv6).  The order of the resolution process and
+      which DNS record takes precedence can either be defined
+      explicitly or may depend on the configuration of the
+      resolver.
+
+      Domain-name values use the US-ASCII encoding.  Their canonical
+      format uses lowercase US-ASCII characters.  Internationalized
+      domain names MUST be A-labels as per RFC 5890.";
+      reference
+        "RFC  952: DoD Internet Host Table Specification
+         RFC 1034: Domain Names - Concepts and Facilities
+         RFC 1123: Requirements for Internet Hosts -- Application
+        	  and Support
+         RFC 2782: A DNS RR for specifying the location of services
+        	  (DNS SRV)
+         RFC 5890: Internationalized Domain Names in Applications
+        	  (IDNA): Definitions and Document Framework";
+
+    }
+
+    typedef host {
+      type union {
+        type ip-address;
+        type domain-name;
+      }
+      description
+        "The host type represents either an IP address or a DNS
+      domain name.";
+    }
+
+    typedef uri {
+      type string;
+      description
+        "The uri type represents a Uniform Resource Identifier
+      (URI) as defined by STD 66.
+
+      Objects using the uri type MUST be in US-ASCII encoding,
+      and MUST be normalized as described by RFC 3986 Sections
+      6.2.1, 6.2.2.1, and 6.2.2.2.  All unnecessary
+      percent-encoding is removed, and all case-insensitive
+      characters are set to lowercase except for hexadecimal
+      digits, which are normalized to uppercase as described in
+      Section 6.2.2.1.
+
+      The purpose of this normalization is to help provide
+      unique URIs.  Note that this normalization is not
+      sufficient to provide uniqueness.  Two URIs that are
+      textually distinct after this normalization may still be
+      equivalent.
+
+      Objects using the uri type may restrict the schemes that
+      they permit.  For example, 'data:' and 'urn:' schemes
+      might not be appropriate.
+
+      A zero-length URI is not a valid URI.  This can be used to
+      express 'URI absent' where required.
+
+      In the value set and its semantics, this type is equivalent
+      to the Uri SMIv2 textual convention defined in RFC 5017.";
+      reference
+        "RFC 3986: Uniform Resource Identifier (URI): Generic Syntax
+         RFC 3305: Report from the Joint W3C/IETF URI Planning Interest
+        	  Group: Uniform Resource Identifiers (URIs), URLs,
+        	  and Uniform Resource Names (URNs): Clarifications
+        	  and Recommendations
+         RFC 5017: MIB Textual Conventions for Uniform Resource
+        	  Identifiers (URIs)";
+
+    }
+  }  // module ietf-inet-types
diff --git a/models/ietf/src/main/yang/ietf-interfaces@2014-05-08.yang b/models/ietf/src/main/yang/ietf-interfaces@2014-05-08.yang
new file mode 100644
index 0000000..d02aca2
--- /dev/null
+++ b/models/ietf/src/main/yang/ietf-interfaces@2014-05-08.yang
@@ -0,0 +1,703 @@
+module ietf-interfaces {
+
+     namespace "urn:ietf:params:xml:ns:yang:ietf-interfaces";
+     prefix if;
+
+     import ietf-yang-types {
+       prefix yang;
+     }
+
+     organization
+       "IETF NETMOD (NETCONF Data Modeling Language) Working Group";
+
+     contact
+       "WG Web:   <http://tools.ietf.org/wg/netmod/>
+        WG List:  <mailto:netmod@ietf.org>
+
+        WG Chair: Thomas Nadeau
+                  <mailto:tnadeau@lucidvision.com>
+
+        WG Chair: Juergen Schoenwaelder
+                  <mailto:j.schoenwaelder@jacobs-university.de>
+
+        Editor:   Martin Bjorklund
+                  <mailto:mbj@tail-f.com>";
+
+     description
+       "This module contains a collection of YANG definitions for
+        managing network interfaces.
+
+        Copyright (c) 2014 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).
+
+        This version of this YANG module is part of RFC 7223; see
+        the RFC itself for full legal notices.";
+
+     revision 2014-05-08 {
+       description
+         "Initial revision.";
+       reference
+         "RFC 7223: A YANG Data Model for Interface Management";
+     }
+
+     /*
+      * Typedefs
+      */
+
+     typedef interface-ref {
+       type leafref {
+         path "/if:interfaces/if:interface/if:name";
+       }
+       description
+         "This type is used by data models that need to reference
+          configured interfaces.";
+     }
+
+     typedef interface-state-ref {
+       type leafref {
+         path "/if:interfaces-state/if:interface/if:name";
+       }
+       description
+         "This type is used by data models that need to reference
+          the operationally present interfaces.";
+     }
+
+     /*
+      * Identities
+      */
+
+     identity interface-type {
+       description
+         "Base identity from which specific interface types are
+          derived.";
+     }
+
+     /*
+      * Features
+      */
+
+     feature arbitrary-names {
+       description
+         "This feature indicates that the device allows user-controlled
+          interfaces to be named arbitrarily.";
+     }
+
+
+     feature pre-provisioning {
+       description
+         "This feature indicates that the device supports
+          pre-provisioning of interface configuration, i.e., it is
+          possible to configure an interface whose physical interface
+          hardware is not present on the device.";
+     }
+
+     feature if-mib {
+       description
+         "This feature indicates that the device implements
+          the IF-MIB.";
+       reference
+         "RFC 2863: The Interfaces Group MIB";
+     }
+
+     /*
+      * Configuration data nodes
+      */
+
+     container interfaces {
+       description
+         "Interface configuration parameters.";
+
+       list interface {
+         key "name";
+
+         description
+           "The list of configured interfaces on the device.
+
+            The operational state of an interface is available in the
+            /interfaces-state/interface list.  If the configuration of a
+            system-controlled interface cannot be used by the system
+            (e.g., the interface hardware present does not match the
+            interface type), then the configuration is not applied to
+            the system-controlled interface shown in the
+            /interfaces-state/interface list.  If the configuration
+            of a user-controlled interface cannot be used by the system,
+            the configured interface is not instantiated in the
+            /interfaces-state/interface list.";
+
+        leaf name {
+           type string;
+           description
+             "The name of the interface.
+
+              A device MAY restrict the allowed values for this leaf,
+              possibly depending on the type of the interface.
+
+
+              For system-controlled interfaces, this leaf is the
+              device-specific name of the interface.  The 'config false'
+              list /interfaces-state/interface contains the currently
+              existing interfaces on the device.
+
+              If a client tries to create configuration for a
+              system-controlled interface that is not present in the
+              /interfaces-state/interface list, the server MAY reject
+              the request if the implementation does not support
+              pre-provisioning of interfaces or if the name refers to
+              an interface that can never exist in the system.  A
+              NETCONF server MUST reply with an rpc-error with the
+              error-tag 'invalid-value' in this case.
+
+              If the device supports pre-provisioning of interface
+              configuration, the 'pre-provisioning' feature is
+              advertised.
+
+              If the device allows arbitrarily named user-controlled
+              interfaces, the 'arbitrary-names' feature is advertised.
+
+              When a configured user-controlled interface is created by
+              the system, it is instantiated with the same name in the
+              /interface-state/interface list.";
+         }
+
+         leaf description {
+           type string;
+           description
+             "A textual description of the interface.
+
+              A server implementation MAY map this leaf to the ifAlias
+              MIB object.  Such an implementation needs to use some
+              mechanism to handle the differences in size and characters
+              allowed between this leaf and ifAlias.  The definition of
+              such a mechanism is outside the scope of this document.
+
+              Since ifAlias is defined to be stored in non-volatile
+              storage, the MIB implementation MUST map ifAlias to the
+              value of 'description' in the persistently stored
+              datastore.
+
+              Specifically, if the device supports ':startup', when
+              ifAlias is read the device MUST return the value of
+              'description' in the 'startup' datastore, and when it is
+              written, it MUST be written to the 'running' and 'startup'
+              datastores.  Note that it is up to the implementation to
+
+              decide whether to modify this single leaf in 'startup' or
+              perform an implicit copy-config from 'running' to
+              'startup'.
+
+              If the device does not support ':startup', ifAlias MUST
+              be mapped to the 'description' leaf in the 'running'
+              datastore.";
+           reference
+             "RFC 2863: The Interfaces Group MIB - ifAlias";
+         }
+
+         leaf type {
+           type identityref {
+             base interface-type;
+           }
+           mandatory true;
+           description
+             "The type of the interface.
+
+              When an interface entry is created, a server MAY
+              initialize the type leaf with a valid value, e.g., if it
+              is possible to derive the type from the name of the
+              interface.
+
+              If a client tries to set the type of an interface to a
+              value that can never be used by the system, e.g., if the
+              type is not supported or if the type does not match the
+              name of the interface, the server MUST reject the request.
+              A NETCONF server MUST reply with an rpc-error with the
+              error-tag 'invalid-value' in this case.";
+           reference
+             "RFC 2863: The Interfaces Group MIB - ifType";
+         }
+
+         leaf enabled {
+           type boolean;
+           default "true";
+           description
+             "This leaf contains the configured, desired state of the
+              interface.
+
+              Systems that implement the IF-MIB use the value of this
+              leaf in the 'running' datastore to set
+              IF-MIB.ifAdminStatus to 'up' or 'down' after an ifEntry
+              has been initialized, as described in RFC 2863.
+
+              Changes in this leaf in the 'running' datastore are
+              reflected in ifAdminStatus, but if ifAdminStatus is
+              changed over SNMP, this leaf is not affected.";
+           reference
+             "RFC 2863: The Interfaces Group MIB - ifAdminStatus";
+         }
+
+         leaf link-up-down-trap-enable {
+           if-feature if-mib;
+           type enumeration {
+             enum enabled {
+               value 1;
+             }
+             enum disabled {
+               value 2;
+             }
+           }
+           description
+             "Controls whether linkUp/linkDown SNMP notifications
+              should be generated for this interface.
+
+              If this node is not configured, the value 'enabled' is
+              operationally used by the server for interfaces that do
+              not operate on top of any other interface (i.e., there are
+              no 'lower-layer-if' entries), and 'disabled' otherwise.";
+           reference
+             "RFC 2863: The Interfaces Group MIB -
+                        ifLinkUpDownTrapEnable";
+         }
+       }
+     }
+
+     /*
+      * Operational state data nodes
+      */
+
+     container interfaces-state {
+       config false;
+       description
+         "Data nodes for the operational state of interfaces.";
+
+       list interface {
+         key "name";
+
+         description
+           "The list of interfaces on the device.
+
+            System-controlled interfaces created by the system are
+            always present in this list, whether they are configured or
+            not.";
+
+         leaf name {
+           type string;
+           description
+             "The name of the interface.
+
+              A server implementation MAY map this leaf to the ifName
+              MIB object.  Such an implementation needs to use some
+              mechanism to handle the differences in size and characters
+              allowed between this leaf and ifName.  The definition of
+              such a mechanism is outside the scope of this document.";
+           reference
+             "RFC 2863: The Interfaces Group MIB - ifName";
+         }
+
+         leaf type {
+           type identityref {
+             base interface-type;
+           }
+           mandatory true;
+           description
+             "The type of the interface.";
+           reference
+             "RFC 2863: The Interfaces Group MIB - ifType";
+         }
+
+         leaf admin-status {
+           if-feature if-mib;
+           type enumeration {
+             enum up {
+               value 1;
+               description
+                 "Ready to pass packets.";
+             }
+             enum down {
+               value 2;
+               description
+                 "Not ready to pass packets and not in some test mode.";
+             }
+
+             enum testing {
+               value 3;
+               description
+                 "In some test mode.";
+             }
+           }
+           mandatory true;
+           description
+             "The desired state of the interface.
+
+              This leaf has the same read semantics as ifAdminStatus.";
+           reference
+             "RFC 2863: The Interfaces Group MIB - ifAdminStatus";
+         }
+
+         leaf oper-status {
+           type enumeration {
+             enum up {
+               value 1;
+               description
+                 "Ready to pass packets.";
+             }
+             enum down {
+               value 2;
+               description
+                 "The interface does not pass any packets.";
+             }
+             enum testing {
+               value 3;
+               description
+                 "In some test mode.  No operational packets can
+                  be passed.";
+             }
+             enum unknown {
+               value 4;
+               description
+                 "Status cannot be determined for some reason.";
+             }
+             enum dormant {
+               value 5;
+               description
+                 "Waiting for some external event.";
+             }
+             enum not-present {
+               value 6;
+               description
+                 "Some component (typically hardware) is missing.";
+             }
+
+             enum lower-layer-down {
+               value 7;
+               description
+                 "Down due to state of lower-layer interface(s).";
+             }
+           }
+           mandatory true;
+           description
+             "The current operational state of the interface.
+
+              This leaf has the same semantics as ifOperStatus.";
+           reference
+             "RFC 2863: The Interfaces Group MIB - ifOperStatus";
+         }
+
+         leaf last-change {
+           type yang:date-and-time;
+           description
+             "The time the interface entered its current operational
+              state.  If the current state was entered prior to the
+              last re-initialization of the local network management
+              subsystem, then this node is not present.";
+           reference
+             "RFC 2863: The Interfaces Group MIB - ifLastChange";
+         }
+
+         leaf if-index {
+           if-feature if-mib;
+           type int32 {
+             range "1..2147483647";
+           }
+           mandatory true;
+           description
+             "The ifIndex value for the ifEntry represented by this
+              interface.";
+           reference
+             "RFC 2863: The Interfaces Group MIB - ifIndex";
+         }
+
+         leaf phys-address {
+           type yang:phys-address;
+           description
+             "The interface's address at its protocol sub-layer.  For
+              example, for an 802.x interface, this object normally
+              contains a Media Access Control (MAC) address.  The
+              interface's media-specific modules must define the bit
+
+
+              and byte ordering and the format of the value of this
+              object.  For interfaces that do not have such an address
+              (e.g., a serial line), this node is not present.";
+           reference
+             "RFC 2863: The Interfaces Group MIB - ifPhysAddress";
+         }
+
+         leaf-list higher-layer-if {
+           type interface-state-ref;
+           description
+             "A list of references to interfaces layered on top of this
+              interface.";
+           reference
+             "RFC 2863: The Interfaces Group MIB - ifStackTable";
+         }
+
+         leaf-list lower-layer-if {
+           type interface-state-ref;
+           description
+             "A list of references to interfaces layered underneath this
+              interface.";
+           reference
+             "RFC 2863: The Interfaces Group MIB - ifStackTable";
+         }
+
+         leaf speed {
+           type yang:gauge64;
+           units "bits/second";
+           description
+               "An estimate of the interface's current bandwidth in bits
+                per second.  For interfaces that do not vary in
+                bandwidth or for those where no accurate estimation can
+                be made, this node should contain the nominal bandwidth.
+                For interfaces that have no concept of bandwidth, this
+                node is not present.";
+           reference
+             "RFC 2863: The Interfaces Group MIB -
+                        ifSpeed, ifHighSpeed";
+         }
+
+
+         container statistics {
+           description
+             "A collection of interface-related statistics objects.";
+
+           leaf discontinuity-time {
+             type yang:date-and-time;
+             mandatory true;
+             description
+               "The time on the most recent occasion at which any one or
+                more of this interface's counters suffered a
+                discontinuity.  If no such discontinuities have occurred
+                since the last re-initialization of the local management
+                subsystem, then this node contains the time the local
+                management subsystem re-initialized itself.";
+           }
+
+           leaf in-octets {
+             type yang:counter64;
+             description
+               "The total number of octets received on the interface,
+                including framing characters.
+
+                Discontinuities in the value of this counter can occur
+                at re-initialization of the management system, and at
+                other times as indicated by the value of
+                'discontinuity-time'.";
+             reference
+               "RFC 2863: The Interfaces Group MIB - ifHCInOctets";
+           }
+
+           leaf in-unicast-pkts {
+             type yang:counter64;
+             description
+               "The number of packets, delivered by this sub-layer to a
+                higher (sub-)layer, that were not addressed to a
+                multicast or broadcast address at this sub-layer.
+
+                Discontinuities in the value of this counter can occur
+                at re-initialization of the management system, and at
+                other times as indicated by the value of
+                'discontinuity-time'.";
+             reference
+               "RFC 2863: The Interfaces Group MIB - ifHCInUcastPkts";
+           }
+
+           leaf in-broadcast-pkts {
+             type yang:counter64;
+             description
+               "The number of packets, delivered by this sub-layer to a
+                higher (sub-)layer, that were addressed to a broadcast
+                address at this sub-layer.
+
+                Discontinuities in the value of this counter can occur
+                at re-initialization of the management system, and at
+                other times as indicated by the value of
+                'discontinuity-time'.";
+             reference
+               "RFC 2863: The Interfaces Group MIB -
+                          ifHCInBroadcastPkts";
+           }
+
+           leaf in-multicast-pkts {
+             type yang:counter64;
+             description
+               "The number of packets, delivered by this sub-layer to a
+                higher (sub-)layer, that were addressed to a multicast
+                address at this sub-layer.  For a MAC-layer protocol,
+                this includes both Group and Functional addresses.
+
+                Discontinuities in the value of this counter can occur
+                at re-initialization of the management system, and at
+                other times as indicated by the value of
+                'discontinuity-time'.";
+             reference
+               "RFC 2863: The Interfaces Group MIB -
+                          ifHCInMulticastPkts";
+           }
+
+           leaf in-discards {
+             type yang:counter32;
+             description
+               "The number of inbound packets that were chosen to be
+                discarded even though no errors had been detected to
+                prevent their being deliverable to a higher-layer
+                protocol.  One possible reason for discarding such a
+                packet could be to free up buffer space.
+
+                Discontinuities in the value of this counter can occur
+                at re-initialization of the management system, and at
+                other times as indicated by the value of
+                'discontinuity-time'.";
+
+             reference
+               "RFC 2863: The Interfaces Group MIB - ifInDiscards";
+           }
+
+           leaf in-errors {
+             type yang:counter32;
+             description
+               "For packet-oriented interfaces, the number of inbound
+                packets that contained errors preventing them from being
+                deliverable to a higher-layer protocol.  For character-
+                oriented or fixed-length interfaces, the number of
+                inbound transmission units that contained errors
+                preventing them from being deliverable to a higher-layer
+                protocol.
+
+                Discontinuities in the value of this counter can occur
+                at re-initialization of the management system, and at
+                other times as indicated by the value of
+                'discontinuity-time'.";
+             reference
+               "RFC 2863: The Interfaces Group MIB - ifInErrors";
+           }
+
+           leaf in-unknown-protos {
+             type yang:counter32;
+             description
+               "For packet-oriented interfaces, the number of packets
+                received via the interface that were discarded because
+                of an unknown or unsupported protocol.  For
+                character-oriented or fixed-length interfaces that
+                support protocol multiplexing, the number of
+                transmission units received via the interface that were
+                discarded because of an unknown or unsupported protocol.
+                For any interface that does not support protocol
+                multiplexing, this counter is not present.
+
+                Discontinuities in the value of this counter can occur
+                at re-initialization of the management system, and at
+                other times as indicated by the value of
+                'discontinuity-time'.";
+             reference
+               "RFC 2863: The Interfaces Group MIB - ifInUnknownProtos";
+           }
+
+           leaf out-octets {
+             type yang:counter64;
+             description
+               "The total number of octets transmitted out of the
+                interface, including framing characters.
+
+                Discontinuities in the value of this counter can occur
+                at re-initialization of the management system, and at
+                other times as indicated by the value of
+                'discontinuity-time'.";
+             reference
+               "RFC 2863: The Interfaces Group MIB - ifHCOutOctets";
+           }
+
+           leaf out-unicast-pkts {
+             type yang:counter64;
+             description
+               "The total number of packets that higher-level protocols
+                requested be transmitted, and that were not addressed
+                to a multicast or broadcast address at this sub-layer,
+                including those that were discarded or not sent.
+
+                Discontinuities in the value of this counter can occur
+                at re-initialization of the management system, and at
+                other times as indicated by the value of
+                'discontinuity-time'.";
+             reference
+               "RFC 2863: The Interfaces Group MIB - ifHCOutUcastPkts";
+           }
+
+           leaf out-broadcast-pkts {
+             type yang:counter64;
+             description
+               "The total number of packets that higher-level protocols
+                requested be transmitted, and that were addressed to a
+                broadcast address at this sub-layer, including those
+                that were discarded or not sent.
+
+                Discontinuities in the value of this counter can occur
+                at re-initialization of the management system, and at
+                other times as indicated by the value of
+                'discontinuity-time'.";
+             reference
+               "RFC 2863: The Interfaces Group MIB -
+                          ifHCOutBroadcastPkts";
+           }
+
+           leaf out-multicast-pkts {
+             type yang:counter64;
+             description
+               "The total number of packets that higher-level protocols
+                requested be transmitted, and that were addressed to a
+                multicast address at this sub-layer, including those
+                that were discarded or not sent.  For a MAC-layer
+                protocol, this includes both Group and Functional
+                addresses.
+
+                Discontinuities in the value of this counter can occur
+                at re-initialization of the management system, and at
+                other times as indicated by the value of
+                'discontinuity-time'.";
+             reference
+               "RFC 2863: The Interfaces Group MIB -
+                          ifHCOutMulticastPkts";
+           }
+
+           leaf out-discards {
+             type yang:counter32;
+             description
+               "The number of outbound packets that were chosen to be
+                discarded even though no errors had been detected to
+                prevent their being transmitted.  One possible reason
+                for discarding such a packet could be to free up buffer
+                space.
+
+                Discontinuities in the value of this counter can occur
+                at re-initialization of the management system, and at
+                other times as indicated by the value of
+                'discontinuity-time'.";
+             reference
+               "RFC 2863: The Interfaces Group MIB - ifOutDiscards";
+           }
+
+           leaf out-errors {
+             type yang:counter32;
+             description
+               "For packet-oriented interfaces, the number of outbound
+                packets that could not be transmitted because of errors.
+                For character-oriented or fixed-length interfaces, the
+                number of outbound transmission units that could not be
+                transmitted because of errors.
+
+                Discontinuities in the value of this counter can occur
+                at re-initialization of the management system, and at
+                other times as indicated by the value of
+                'discontinuity-time'.";
+             reference
+               "RFC 2863: The Interfaces Group MIB - ifOutErrors";
+           }
+         }
+       }
+     }
+   }
diff --git a/models/ietf/src/main/yang/ietf-yang-types@2013-07-15.yang b/models/ietf/src/main/yang/ietf-yang-types@2013-07-15.yang
new file mode 100644
index 0000000..9a543fa
--- /dev/null
+++ b/models/ietf/src/main/yang/ietf-yang-types@2013-07-15.yang
@@ -0,0 +1,490 @@
+  module ietf-yang-types {
+
+    yang-version 1;
+
+    namespace
+      "urn:ietf:params:xml:ns:yang:ietf-yang-types";
+
+    prefix yang;
+
+    organization
+      "IETF NETMOD (NETCONF Data Modeling Language) Working Group";
+
+    contact
+      "WG Web:   <http://tools.ietf.org/wg/netmod/>
+    WG List:  <mailto:netmod@ietf.org>
+
+    WG Chair: David Kessens
+              <mailto:david.kessens@nsn.com>
+
+    WG Chair: Juergen Schoenwaelder
+              <mailto:j.schoenwaelder@jacobs-university.de>
+
+    Editor:   Juergen Schoenwaelder
+              <mailto:j.schoenwaelder@jacobs-university.de>";
+
+    description
+      "This module contains a collection of generally useful derived
+    YANG data types.
+
+    Copyright (c) 2013 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).
+
+    This version of this YANG module is part of RFC 6991; see
+    the RFC itself for full legal notices.";
+
+    revision "2013-07-15" {
+      description
+        "This revision adds the following new data types:
+      - yang-identifier
+      - hex-string
+      - uuid
+      - dotted-quad";
+      reference
+        "RFC 6991: Common YANG Data Types";
+
+    }
+
+    revision "2010-09-24" {
+      description "Initial revision.";
+      reference
+        "RFC 6021: Common YANG Data Types";
+
+    }
+
+
+    typedef counter32 {
+      type uint32;
+      description
+        "The counter32 type represents a non-negative integer
+      that monotonically increases until it reaches a
+      maximum value of 2^32-1 (4294967295 decimal), when it
+      wraps around and starts increasing again from zero.
+
+      Counters have no defined 'initial' value, and thus, a
+      single value of a counter has (in general) no information
+      content.  Discontinuities in the monotonically increasing
+      value normally occur at re-initialization of the
+      management system, and at other times as specified in the
+      description of a schema node using this type.  If such
+      other times can occur, for example, the creation of
+      a schema node of type counter32 at times other than
+      re-initialization, then a corresponding schema node
+      should be defined, with an appropriate type, to indicate
+      the last discontinuity.
+
+      The counter32 type should not be used for configuration
+      schema nodes.  A default statement SHOULD NOT be used in
+      combination with the type counter32.
+
+      In the value set and its semantics, this type is equivalent
+      to the Counter32 type of the SMIv2.";
+      reference
+        "RFC 2578: Structure of Management Information Version 2
+        	  (SMIv2)";
+
+    }
+
+    typedef zero-based-counter32 {
+      type counter32;
+      default "0";
+      description
+        "The zero-based-counter32 type represents a counter32
+      that has the defined 'initial' value zero.
+
+      A schema node of this type will be set to zero (0) on creation
+      and will thereafter increase monotonically until it reaches
+      a maximum value of 2^32-1 (4294967295 decimal), when it
+      wraps around and starts increasing again from zero.
+
+      Provided that an application discovers a new schema node
+      of this type within the minimum time to wrap, it can use the
+      'initial' value as a delta.  It is important for a management
+      station to be aware of this minimum time and the actual time
+      between polls, and to discard data if the actual time is too
+      long or there is no defined minimum time.
+
+      In the value set and its semantics, this type is equivalent
+      to the ZeroBasedCounter32 textual convention of the SMIv2.";
+      reference
+        "RFC 4502: Remote Network Monitoring Management Information
+        	  Base Version 2";
+
+    }
+
+    typedef counter64 {
+      type uint64;
+      description
+        "The counter64 type represents a non-negative integer
+      that monotonically increases until it reaches a
+      maximum value of 2^64-1 (18446744073709551615 decimal),
+      when it wraps around and starts increasing again from zero.
+
+      Counters have no defined 'initial' value, and thus, a
+      single value of a counter has (in general) no information
+      content.  Discontinuities in the monotonically increasing
+      value normally occur at re-initialization of the
+      management system, and at other times as specified in the
+      description of a schema node using this type.  If such
+      other times can occur, for example, the creation of
+      a schema node of type counter64 at times other than
+      re-initialization, then a corresponding schema node
+      should be defined, with an appropriate type, to indicate
+      the last discontinuity.
+
+      The counter64 type should not be used for configuration
+      schema nodes.  A default statement SHOULD NOT be used in
+      combination with the type counter64.
+
+      In the value set and its semantics, this type is equivalent
+      to the Counter64 type of the SMIv2.";
+      reference
+        "RFC 2578: Structure of Management Information Version 2
+        	  (SMIv2)";
+
+    }
+
+    typedef zero-based-counter64 {
+      type counter64;
+      default "0";
+      description
+        "The zero-based-counter64 type represents a counter64 that
+      has the defined 'initial' value zero.
+
+
+
+
+      A schema node of this type will be set to zero (0) on creation
+      and will thereafter increase monotonically until it reaches
+      a maximum value of 2^64-1 (18446744073709551615 decimal),
+      when it wraps around and starts increasing again from zero.
+
+      Provided that an application discovers a new schema node
+      of this type within the minimum time to wrap, it can use the
+      'initial' value as a delta.  It is important for a management
+      station to be aware of this minimum time and the actual time
+      between polls, and to discard data if the actual time is too
+      long or there is no defined minimum time.
+
+      In the value set and its semantics, this type is equivalent
+      to the ZeroBasedCounter64 textual convention of the SMIv2.";
+      reference
+        "RFC 2856: Textual Conventions for Additional High Capacity
+        	  Data Types";
+
+    }
+
+    typedef gauge32 {
+      type uint32;
+      description
+        "The gauge32 type represents a non-negative integer, which
+      may increase or decrease, but shall never exceed a maximum
+      value, nor fall below a minimum value.  The maximum value
+      cannot be greater than 2^32-1 (4294967295 decimal), and
+      the minimum value cannot be smaller than 0.  The value of
+      a gauge32 has its maximum value whenever the information
+      being modeled is greater than or equal to its maximum
+      value, and has its minimum value whenever the information
+      being modeled is smaller than or equal to its minimum value.
+      If the information being modeled subsequently decreases
+      below (increases above) the maximum (minimum) value, the
+      gauge32 also decreases (increases).
+
+      In the value set and its semantics, this type is equivalent
+      to the Gauge32 type of the SMIv2.";
+      reference
+        "RFC 2578: Structure of Management Information Version 2
+        	  (SMIv2)";
+
+    }
+
+    typedef gauge64 {
+      type uint64;
+      description
+        "The gauge64 type represents a non-negative integer, which
+      may increase or decrease, but shall never exceed a maximum
+      value, nor fall below a minimum value.  The maximum value
+      cannot be greater than 2^64-1 (18446744073709551615), and
+      the minimum value cannot be smaller than 0.  The value of
+      a gauge64 has its maximum value whenever the information
+      being modeled is greater than or equal to its maximum
+      value, and has its minimum value whenever the information
+      being modeled is smaller than or equal to its minimum value.
+      If the information being modeled subsequently decreases
+      below (increases above) the maximum (minimum) value, the
+      gauge64 also decreases (increases).
+
+      In the value set and its semantics, this type is equivalent
+      to the CounterBasedGauge64 SMIv2 textual convention defined
+      in RFC 2856";
+      reference
+        "RFC 2856: Textual Conventions for Additional High Capacity
+        	  Data Types";
+
+    }
+
+    typedef object-identifier {
+      type string {
+        pattern
+          '(([0-1](\.[1-3]?[0-9]))|(2\.(0|([1-9]\d*))))(\.(0|([1-9]\d*)))*';
+      }
+      description
+        "The object-identifier type represents administratively
+      assigned names in a registration-hierarchical-name tree.
+
+      Values of this type are denoted as a sequence of numerical
+      non-negative sub-identifier values.  Each sub-identifier
+      value MUST NOT exceed 2^32-1 (4294967295).  Sub-identifiers
+      are separated by single dots and without any intermediate
+      whitespace.
+
+      The ASN.1 standard restricts the value space of the first
+      sub-identifier to 0, 1, or 2.  Furthermore, the value space
+      of the second sub-identifier is restricted to the range
+      0 to 39 if the first sub-identifier is 0 or 1.  Finally,
+      the ASN.1 standard requires that an object identifier
+      has always at least two sub-identifiers.  The pattern
+      captures these restrictions.
+
+      Although the number of sub-identifiers is not limited,
+      module designers should realize that there may be
+      implementations that stick with the SMIv2 limit of 128
+      sub-identifiers.
+
+      This type is a superset of the SMIv2 OBJECT IDENTIFIER type
+      since it is not restricted to 128 sub-identifiers.  Hence,
+      this type SHOULD NOT be used to represent the SMIv2 OBJECT
+      IDENTIFIER type; the object-identifier-128 type SHOULD be
+      used instead.";
+      reference
+        "ISO9834-1: Information technology -- Open Systems
+        Interconnection -- Procedures for the operation of OSI
+        Registration Authorities: General procedures and top
+        arcs of the ASN.1 Object Identifier tree";
+
+    }
+
+    typedef object-identifier-128 {
+      type object-identifier {
+        pattern '\d*(\.\d*){1,127}';
+      }
+      description
+        "This type represents object-identifiers restricted to 128
+      sub-identifiers.
+
+      In the value set and its semantics, this type is equivalent
+      to the OBJECT IDENTIFIER type of the SMIv2.";
+      reference
+        "RFC 2578: Structure of Management Information Version 2
+        	  (SMIv2)";
+
+    }
+
+    typedef yang-identifier {
+      type string {
+        length "1..max";
+        pattern '[a-zA-Z_][a-zA-Z0-9\-_.]*';
+        pattern
+          '.|..|[^xX].*|.[^mM].*|..[^lL].*';
+      }
+      description
+        "A YANG identifier string as defined by the 'identifier'
+       rule in Section 12 of RFC 6020.  An identifier must
+       start with an alphabetic character or an underscore
+       followed by an arbitrary sequence of alphabetic or
+       numeric characters, underscores, hyphens, or dots.
+
+       A YANG identifier MUST NOT start with any possible
+       combination of the lowercase or uppercase character
+       sequence 'xml'.";
+      reference
+        "RFC 6020: YANG - A Data Modeling Language for the Network
+        	  Configuration Protocol (NETCONF)";
+
+    }
+
+    typedef date-and-time {
+      type string {
+        pattern
+          '\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(\.\d+)?(Z|[\+\-]\d{2}:\d{2})';
+      }
+      description
+        "The date-and-time type is a profile of the ISO 8601
+      standard for representation of dates and times using the
+      Gregorian calendar.  The profile is defined by the
+      date-time production in Section 5.6 of RFC 3339.
+
+      The date-and-time type is compatible with the dateTime XML
+      schema type with the following notable exceptions:
+
+      (a) The date-and-time type does not allow negative years.
+
+      (b) The date-and-time time-offset -00:00 indicates an unknown
+          time zone (see RFC 3339) while -00:00 and +00:00 and Z
+          all represent the same time zone in dateTime.
+
+      (c) The canonical format (see below) of data-and-time values
+          differs from the canonical format used by the dateTime XML
+          schema type, which requires all times to be in UTC using
+          the time-offset 'Z'.
+
+      This type is not equivalent to the DateAndTime textual
+      convention of the SMIv2 since RFC 3339 uses a different
+      separator between full-date and full-time and provides
+      higher resolution of time-secfrac.
+
+      The canonical format for date-and-time values with a known time
+      zone uses a numeric time zone offset that is calculated using
+      the device's configured known offset to UTC time.  A change of
+      the device's offset to UTC time will cause date-and-time values
+      to change accordingly.  Such changes might happen periodically
+      in case a server follows automatically daylight saving time
+      (DST) time zone offset changes.  The canonical format for
+      date-and-time values with an unknown time zone (usually
+      referring to the notion of local time) uses the time-offset
+      -00:00.";
+      reference
+        "RFC 3339: Date and Time on the Internet: Timestamps
+         RFC 2579: Textual Conventions for SMIv2
+        XSD-TYPES: XML Schema Part 2: Datatypes Second Edition";
+
+    }
+
+    typedef timeticks {
+      type uint32;
+      description
+        "The timeticks type represents a non-negative integer that
+      represents the time, modulo 2^32 (4294967296 decimal), in
+      hundredths of a second between two epochs.  When a schema
+      node is defined that uses this type, the description of
+      the schema node identifies both of the reference epochs.
+
+      In the value set and its semantics, this type is equivalent
+      to the TimeTicks type of the SMIv2.";
+      reference
+        "RFC 2578: Structure of Management Information Version 2
+        	  (SMIv2)";
+
+    }
+
+    typedef timestamp {
+      type timeticks;
+      description
+        "The timestamp type represents the value of an associated
+      timeticks schema node at which a specific occurrence
+      happened.  The specific occurrence must be defined in the
+      description of any schema node defined using this type.  When
+      the specific occurrence occurred prior to the last time the
+      associated timeticks attribute was zero, then the timestamp
+      value is zero.  Note that this requires all timestamp values
+      to be reset to zero when the value of the associated timeticks
+      attribute reaches 497+ days and wraps around to zero.
+
+      The associated timeticks schema node must be specified
+      in the description of any schema node using this type.
+
+      In the value set and its semantics, this type is equivalent
+      to the TimeStamp textual convention of the SMIv2.";
+      reference
+        "RFC 2579: Textual Conventions for SMIv2";
+
+    }
+
+    typedef phys-address {
+      type string {
+        pattern
+          '([0-9a-fA-F]{2}(:[0-9a-fA-F]{2})*)?';
+      }
+      description
+        "Represents media- or physical-level addresses represented
+      as a sequence octets, each octet represented by two hexadecimal
+      numbers.  Octets are separated by colons.  The canonical
+      representation uses lowercase characters.
+
+      In the value set and its semantics, this type is equivalent
+      to the PhysAddress textual convention of the SMIv2.";
+      reference
+        "RFC 2579: Textual Conventions for SMIv2";
+
+    }
+
+    typedef mac-address {
+      type string {
+        pattern
+          '[0-9a-fA-F]{2}(:[0-9a-fA-F]{2}){5}';
+      }
+      description
+        "The mac-address type represents an IEEE 802 MAC address.
+      The canonical representation uses lowercase characters.
+
+      In the value set and its semantics, this type is equivalent
+      to the MacAddress textual convention of the SMIv2.";
+      reference
+        "IEEE 802: IEEE Standard for Local and Metropolitan Area
+        	  Networks: Overview and Architecture
+         RFC 2579: Textual Conventions for SMIv2";
+
+    }
+
+    typedef xpath1.0 {
+      type string;
+      description
+        "This type represents an XPATH 1.0 expression.
+
+      When a schema node is defined that uses this type, the
+      description of the schema node MUST specify the XPath
+      context in which the XPath expression is evaluated.";
+      reference
+        "XPATH: XML Path Language (XPath) Version 1.0";
+
+    }
+
+    typedef hex-string {
+      type string {
+        pattern
+          '([0-9a-fA-F]{2}(:[0-9a-fA-F]{2})*)?';
+      }
+      description
+        "A hexadecimal string with octets represented as hex digits
+      separated by colons.  The canonical representation uses
+      lowercase characters.";
+    }
+
+    typedef uuid {
+      type string {
+        pattern
+          '[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}';
+      }
+      description
+        "A Universally Unique IDentifier in the string representation
+      defined in RFC 4122.  The canonical representation uses
+      lowercase characters.
+
+      The following is an example of a UUID in string representation:
+      f81d4fae-7dec-11d0-a765-00a0c91e6bf6
+      ";
+      reference
+        "RFC 4122: A Universally Unique IDentifier (UUID) URN
+        	  Namespace";
+
+    }
+
+    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 number expressed in the dotted-quad
+       notation, i.e., four octets written as decimal numbers
+       and separated with the '.' (full stop) character.";
+    }
+  }  // module ietf-yang-types
+