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Versions: 00

Network Working Group                                         A. Bierman
Internet-Draft                                                 YumaWorks
Intended status: Standards Track                          March 10, 2019
Expires: September 11, 2019


                         Module Tag Operations
                draft-bierman-netconf-module-tag-ops-00

Abstract

   This document describes enhancements to existing NETCONF and RESTCONF
   (NMDA) operations for using module tags to represent YANG datastore
   content.  This can simplify usage of these operations by a client.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on September 11, 2019.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.





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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   2
       1.1.1.  NMDA  . . . . . . . . . . . . . . . . . . . . . . . .   3
       1.1.2.  RESTCONF  . . . . . . . . . . . . . . . . . . . . . .   3
       1.1.3.  YANG  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Tree Diagrams . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Module Tag Operations . . . . . . . . . . . . . . . . . . . .   4
     2.1.  Module Tag Filters  . . . . . . . . . . . . . . . . . . .   4
       2.1.1.  NETCONF "module-tag" RPC Input Parameter  . . . . . .   5
       2.1.2.  RESTCONF "module-tag" Query Parameter . . . . . . . .   5
     2.2.  NACM "module-tags" Rule Type  . . . . . . . . . . . . . .   5
   3.  Definitions . . . . . . . . . . . . . . . . . . . . . . . . .   5
     3.1.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .   6
     3.2.  RESTCONF Query Parameter  . . . . . . . . . . . . . . . .  10
     3.3.  RESTCONF Query Parameter Capability . . . . . . . . . . .  10
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .  12
     6.2.  Informative References  . . . . . . . . . . . . . . . . .  13
   Appendix A.  Examples . . . . . . . . . . . . . . . . . . . . . .  13
     A.1.  NETCONF <get-data> Example  . . . . . . . . . . . . . . .  13
     A.2.  RESTCONF GET Example  . . . . . . . . . . . . . . . . . .  14
     A.3.  NACM Example  . . . . . . . . . . . . . . . . . . . . . .  15
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

   There is a need for standard mechanisms to allow NETCONF [RFC6241]
   and RESTCONF [RFC8040] protocol operations, as well as NMDA
   operations for NETCONF [RFC8526] and RESTCONF [RFC8527], to utilize
   the module tag mapping definitions defined in
   [I-D.ietf-netmod-module-tags].  Netconf Access Control rules defined
   in [RFC8341] can also utilize module tags to simplify access control
   rule configuration.

1.1.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.






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1.1.1.  NMDA

   The following terms are defined in the Network Management Datastore
   Architecture (NMDA) [RFC8342]:

   o  configuration

   o  client

   o  datastore

   o  notification

   o  operational state

   o  operational state datastore

   o  server

1.1.2.  RESTCONF

   The following terms are defined in [RFC8040]:

   o  data resource

   o  target resource

1.1.3.  YANG

   The following terms are defined in [RFC7950]:

   o  choice

   o  container

   o  data model

   o  data node

   o  grouping

   o  leaf

   o  leaf-list

   o  list





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1.2.  Tree Diagrams

   Tree diagrams used in this document follow the notation defined in
   [RFC8340].

2.  Module Tag Operations

   A module tag is a string associated with a module name.  Modules are
   associated with the same module tag for the purpose of simplifying
   protocol operations, and other tool-specific operations.

   The definition and management of module tags is defined in the ietf-
   module-tags module.  This document defines augmentations to NETCONF
   protocol operations that use module tags defined in that module to
   represent YANG datastore content instead of a list of module names or
   data nodes.

   A server vendor and operator can install module to module tag
   mappings on a server, using the ietf-module-tags YANG module.
   Support for that module is required to utilize the mechanisms defined
   in this document.

   The following tree diagram shows the 4 separate augmentations defined
   in this module:

     module: ietf-module-tag-ops
       augment /ncds:get-data/ncds:input:
         +---w module-tag*   tags:tag
       augment /nacm:nacm/nacm:rule-list/nacm:rule/nacm:rule-type:
         +--:(module-tags)
            +--rw module-tag*   tags:tag
       augment /nc:get-config/nc:input:
         +---w module-tag*   tags:tag
       augment /nc:get/nc:input:
         +---w module-tag*   tags:tag

2.1.  Module Tag Filters

   Data retrieval filters based on module tags allow an operator to
   easily include only data of specific interest, without having to know
   the exact path identifiers for these objects within the datastore.
   Module tags can be pre-defined in the YANG module or YANG Module Tags
   Registry ([I-D.ietf-netmod-module-tags], sec. 7.2).  Module tag
   mappings can also be pre-installed by the server vendor, so no
   complex setup is required by an operator to use module tag filters.

   The NETCONF and RESTCONF protocols do not have any way to select
   content by module name at all.  In every case, either all content is



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   included or specific data node paths have to be provided by the
   client to include the associated data instances.

2.1.1.  NETCONF "module-tag" RPC Input Parameter

   The NETCONF protocol has 2 non-NMDA [RFC6241] retrieval operations
   (<get-config> and <get>) and 1 NMDA [RFC8526] retrieval operation
   (<get-data>).  This document defines a "module-tag" grouping that is
   used an additional rpc input parameter for each operation.  It can be
   applied to all server content that is accessible with these protocol
   operations.

2.1.2.  RESTCONF "module-tag" Query Parameter

   The RESTCONF protocol has a GET operation that allows query
   parameters to be provided to modify the retrieval operation.  This
   document defines a new query parameter named "module-tag" that has
   the same semantics as the "module-tag" YANG data node definition.  It
   also defines a RESTCONF Capability URN for a server to indicate that
   this query parameter is supported.

2.2.  NACM "module-tags" Rule Type

   The Network Configuration Access Control Protocol (NACM) [RFC8341]
   allows access control entries to apply to one module or all modules.
   This document defines a new "rule-type" case within a "rule" list
   entry, which allows the access control rule to apply to all the
   modules associated with one or more module tag values.

   This new rule type is intended to replace the "module-name" parameter
   in the "rule" list entry.  Module tag filters are intended to be used
   with the default "module-name" value "*" to represent all modules.
   This new "module-tags" rule imposes new restrictions on the rule
   selection, so it is backward compatible with the definitions in
   [RFC8341].

   NACM rules using the "module-tag" parameter within the new
   "module-tags" case can be applied to configuration data, operational
   state, protocol operations and notification events.  This rule type
   works exactly the same way as the "module-name" leaf within the
   "rule" list entry, except it applies to all associated module names,
   instead of one.

3.  Definitions







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3.1.  YANG Module

   This module imports definitions from [I-D.ietf-netmod-module-tags],
   [RFC6241], [RFC8341], and [RFC8526].

   <CODE BEGINS> file "ietf-module-tag-ops@2019-03-10.yang"

   module ietf-module-tag-ops {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-module-tag-ops";

     prefix mto;

     import ietf-module-tags { prefix tags; }
     import ietf-netconf { prefix nc; }
     import ietf-netconf-acm { prefix nacm; }
     import ietf-netconf-nmda { prefix ncds; }

     organization
       "IETF NETCONF (Network Configuration) Working Group";

     contact
       "WG Web:   <http://tools.ietf.org/wg/netconf/>
        WG List:  <mailto:netconf@ietf.org>

        Author:   Andy Bierman
                  <mailto:andy@yumaworks.com>";

     description
       "This module defines enhancements to existing NETCONF
        operations for using module tags to represent
        YANG datastore content.

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
        'MAY', and 'OPTIONAL' in this document are to be interpreted as
        described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
        they appear in all capitals, as shown here.

        Copyright (c) 2019 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).";



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     // RFC Ed.: update the date below with the date of RFC publication
     // and remove this note.

     revision 2019-03-10 {
       description
         "Initial revision.";
       reference
         "draft-bierman-netconf-module-tag-ops-00";
     }

     grouping module-tag {
       description
         "Contains a reusable module-tag filter parameter";

       leaf-list module-tag {
         type tags:tag;
         description
           "Include only data nodes that match the module-tag
            value. A data node is matched to a module tag in the
            following manner:

             1) The module name associated with the data node
                is determined according to the protocol and
                message encoding.

             2) The module name is associated with the specified
                module-tag if a 'tag' entry exists within a
                /module-tags/module list entry with the same
                value as this entry, and a 'masked-tag' entry
                does not exist within the same /module-tags/module
                list entry.

             3) Each child data node is tested in recursive fashion.
                If the module name changes from the parent node, then
                this procedure is repeated. Once a module name
                does not match, then no further descendant nodes
                are included.

            Multiple module-tag parameters are combined as a
            logical OR expression. Matching any tag value will
            cause the data node to be included.

            It is not an error to include an unknown module-tag
            value. Such tag values will simply be treated as a 'false'
            match result, when evaluating the filter.

            If any module-tag parameters are provided at all,
            and there are no matches found, then no data will be



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            returned in the response.

            The output of all module-tag parameters are
            combined with other retrieval filters in a logical
            AND expression.
           ";
         }
       }

       augment /ncds:get-data/ncds:input {
         description
           "Return data only if it matches according
            to the rules specified in the module-tag parameter.";
         uses module-tag {
           description
             "The module-tag values are applied starting at the
              top-level YANG data node within the target datastore.";
           reference
             "RFC 8526: NETCONF Extensions to Support the
              Network Management Datastore Architecture; Section 3.1.1";
         }
       }

       augment /nacm:nacm/nacm:rule-list/nacm:rule/nacm:rule-type {
         description
           "Match datastore content, protocol operations, or
            notification events only if the associated module name
            matches according to the rules specified in the module-tag
            parameter.

            If this rule type is used then the associated module-name
            parameter needs to be omitted or set to the default value.
            Otherwise it will interact with the module-tag parameter
            and the specified module-name will only apply if it is
            also included in the module-tag parameters provided.";

         case module-tags {
           uses module-tag {
             description
               "The module-tag values are applied to the conceptual
                document according to the NACM rules, starting at the
                top-level YANG data node. This is different in each
                access control enforcement procedure phase:

                - Incoming RPC Message Validation
                  The module name of the association protocol operation
                  is used to match a module-tag parameter.




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                - Data Node Access Validation
                  The module name associated with each data node within
                  the target datastore, or within non-NMDA operational
                  state (in an implementation-specific manner).

                - Outgoing <notification> Authorization:
                  The module name of the association notification event
                  is used to match a module-tag parameter.
               ";
             reference
               "RFC 8341: Network Configuration Access Control Model;
                Sections 3.2.4, 3.4.4, 3.5.5, 3.4.6";
           }
         }
       }

       augment /nc:get-config/nc:input {
         status deprecated;
         description
           "Return configuration data only if it matches according
            to the rules specified in the module-tag parameter.";
         uses module-tag {
           status deprecated;
           description
             "The module-tag values are applied starting at the
              top-level YANG data node within the target datastore.";
           reference
             "RFC 6241: Network Configuration Protocol; Section 7.1";
         }
       }

       augment /nc:get/nc:input {
         status deprecated;
         description
           "Return data only if it matches according
            to the rules specified in the module-tag parameter.";
         uses module-tag {
           status deprecated;
           description
             "The module-tag values are applied starting at the
              top-level YANG data node within the <running> datastore
              for configuration and the top-level YANG data nodes
              for all operational state data nodes.";
           reference
             "RFC 6241: Network Configuration Protocol; Section 7.7";
         }
       }




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   }

   <CODE ENDS>

3.2.  RESTCONF Query Parameter

   The "module-tag" parameter can be used as a query parameter in a
   RESTCONF protocol GET operation.  This new query parameter can be
   applied to any data resource that is retrievable from the server.
   This is done using the "{+restconf}/data" resource defined in section
   3.3.1 of [RFC8040], or any datastore resource defined in section 3.1
   of [RFC8527].

   The retrieval filtering is processed exactly the same as the
   "module-tag" parameter for NETCONF, defined in Section 3.1.

   The module tag filtering starts with the top-level data nodes, the
   same as for NETCONF.  All data nodes specified in the target resource
   are subject to the same module-tag filter test as data nodes within
   the target resource.

3.3.  RESTCONF Query Parameter Capability

   The following RESTCONF Capability URI is defined to indicate that the
   module-tag query parameter is supported by a RESTCONF server.  It
   MUST be advertised as a "capability" in the /restconf-
   state/capabilities/capability leaf-list.

   The server MUST support the "module-tag" query parameter for GET and
   HEAD methods if this capability is advertised.

4.  IANA Considerations

   This document registers one URI as a namespace in the "IETF XML
   Registry" [RFC3688]:

      URI: urn:ietf:params:xml:ns:yang:ietf-module-tag-ops
      Registrant Contact: The IESG.
      XML: N/A; the requested URI is an XML namespace.

   This document registers one YANG module in the "YANG Module Names"
   registry [RFC6020]:

      name:         ietf-module-tag-ops
      namespace:    urn:ietf:params:xml:ns:yang:ietf-module-tag-ops
      prefix:       sx
      // RFC Ed.: replace XXXX with RFC number and remove this note
      reference:    RFC XXXX



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   This document registers one RESTCONF Capability URN in the registry
   defined in [RFC8040]:

      name:         :module-tag
      URN:          urn:ietf:params:restconf:capability:module-tag:1.0
      // RFC Ed.: replace XXXX with RFC number and remove this note
      reference:    RFC XXXX

5.  Security Considerations

   The YANG module specified in this document defines a schema for data
   that is designed to be accessed via network management protocols such
   as NETCONF [RFC6241] or RESTCONF [RFC8040].  The lowest NETCONF layer
   is the secure transport layer, and the mandatory-to-implement secure
   transport is Secure Shell (SSH) [RFC6242].  The lowest RESTCONF layer
   is HTTPS, and the mandatory-to-implement secure transport is TLS
   [RFC8446].

   The NETCONF access control model [RFC8341] provides the means to
   restrict access for particular NETCONF or RESTCONF users to a
   preconfigured subset of all available NETCONF or RESTCONF protocol
   operations and content.

   There is one data node defined in this YANG module that is
   writable/creatable/deletable (i.e., "config true", which is the
   default).  These data nodes may be considered sensitive or vulnerable
   in some network environments.  Write operations (e.g., edit-config)

   to these data nodes without proper protection can have a negative
   effect on network operations.  These are the subtrees and data nodes
   and their sensitivity/vulnerability:

      /nacm/rule-list/rule/module-tag

   This object allows an access control rule to be configured based on a
   module tag mapping.  This object is vurnerable to modifications to
   the /module-tags configuration within the server.  Care must be taken
   not to allow users to modify the /module-tags contents in a way that
   will expose protocol access in an unauthorized manner.

   Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control read access (e.g., via get, get-config, or
   notification) to these data nodes.  These are the subtrees and data
   nodes and their sensitivity/vulnerability:

      /nacm/rule-list/rule/module-tag




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   This object allows an access control rule to be configured based on a
   module tag mapping.  Allowing read access to this object can expose
   the access control rule details.

6.  References

6.1.  Normative References

   [I-D.ietf-netmod-module-tags]
              Hopps, C., Berger, L., and D. Bogdanovic, "YANG Module
              Tags", draft-ietf-netmod-module-tags-07 (work in
              progress), March 2019.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <https://www.rfc-editor.org/info/rfc6241>.

   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
              Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
              <https://www.rfc-editor.org/info/rfc6242>.

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <https://www.rfc-editor.org/info/rfc7950>.

   [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
              <https://www.rfc-editor.org/info/rfc8040>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8340]  Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
              BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
              <https://www.rfc-editor.org/info/rfc8340>.

   [RFC8341]  Bierman, A. and M. Bjorklund, "Network Configuration
              Access Control Model", STD 91, RFC 8341,
              DOI 10.17487/RFC8341, March 2018,
              <https://www.rfc-editor.org/info/rfc8341>.




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   [RFC8342]  Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
              and R. Wilton, "Network Management Datastore Architecture
              (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
              <https://www.rfc-editor.org/info/rfc8342>.

   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.

   [RFC8526]  Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
              and R. Wilton, "NETCONF Extensions to Support the Network
              Management Datastore Architecture", RFC 8526,
              DOI 10.17487/RFC8526, March 2019,
              <https://www.rfc-editor.org/info/rfc8526>.

   [RFC8527]  Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
              and R. Wilton, "RESTCONF Extensions to Support the Network
              Management Datastore Architecture", RFC 8527,
              DOI 10.17487/RFC8527, March 2019,
              <https://www.rfc-editor.org/info/rfc8527>.

6.2.  Informative References

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <https://www.rfc-editor.org/info/rfc3688>.

   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <https://www.rfc-editor.org/info/rfc6020>.

   [RFC8348]  Bierman, A., Bjorklund, M., Dong, J., and D. Romascanu, "A
              YANG Data Model for Hardware Management", RFC 8348,
              DOI 10.17487/RFC8348, March 2018,
              <https://www.rfc-editor.org/info/rfc8348>.

Appendix A.  Examples

A.1.  NETCONF <get-data> Example

   This example uses the module tag value "ietf:hardware" which is
   defined in the YANG Module Tags registry.  It is assumed in this case
   to be mapped on the server to the "ietf-hardware" module defined in
   [RFC8348].

   Note that some lines are incorrectly wrapped in the examples below
   for display purposes only.



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   The server might send the following <get-data> request on the
   operational state datastore:

   <rpc message-id="101"
     xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <get-data xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-nmda"
          xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">
       <datastore>ds:operational</datastore>
       <mto:module-tag
           xmlns:mto="urn:ietf:params:xml:ns:yang:ietf-module-tag-ops">
         ietf:hardware
       </mto:module-tag>
      </get-data>
   </rpc>

   The server might send the following reply:

  <rpc-reply message-id="101"
     xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
    <data xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-nmda">
      <hw:hardware xmlns:hw="urn:ietf:params:xml:ns:yang:ietf-hardware">
        <!-- rest of descendant nodes that match the module-tag -->
      </hw:hardware>
    </data>
  </rpc-reply>

A.2.  RESTCONF GET Example

   This example uses the same module-tag and server assumptions as
   Appendix A.1.

   The client might send the following request:

  GET /restconf/ds/ietf-datastores:operational?module-tag=ietf:hardware\
    HTTP/1.1
  Host: example.com
  Accept: application/yang-data+json

   The server might respond as follows.  The contents of the "hardware"
   container are omitted for brevity.











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     HTTP/1.1 200 OK
     Date: Thu, 26 Feb 2019 20:56:30 GMT
     Server: example-server
     Content-Type: application/yang-data+json

     {
       "ietf-hardware:hardware": {

       }
     }

A.3.  NACM Example

   In this example, a module tag rule is created to deny guests all
   access to hardware information.

   Note that some lines are incorrectly wrapped in the example below for
   display purposes only.

    <nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">
      <rule-list>
        <name>guest-acl</name>
        <group>guest</group>
        <rule>
          <name>deny-hw</name>
          <mto:module-tag
            xmlns:mto="urn:ietf:params:xml:ns:yang:ietf-module-tag-ops">
          ietf:hardware</mto:module-tag>
          <access-operations>*</access-operations>
          <action>deny</action>
          <comment>
             Do not allow guests to access any hardware information
          </comment>
        </rule>
      </rule-list>
    </nacm>

Author's Address

   Andy Bierman
   YumaWorks

   Email: andy@yumaworks.com








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