A Verification Proceedure for Configuration Management within NETCONF
draft-cole-netconf-verify-00

Abstract

This document extends the capabilities of the NETCONF configuration management protocol in order to standardize mechanisms to perform sets of active tests (i.e., verification) against servers' running configuration over a period of time to afford the client and server a more robust and resilient configuration management capability. This is of value to commercial enterprise and public networks as well as wireless emergency and military networks. We propose an initial new NETCONF capability, i.e., verify. The verify capability is defined in the context of the verify.yang module listed in the appendix of this document. Associated with the verify operation are various test.yang modules to be defined elsewhere. However, this document defines a set of interoperability requirements on the development of the test.yang modules in order to be controlled through the verify capability.

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 http://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 January 6, 2011.

Copyright Notice

Copyright (c) 2010 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 (http://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.

Table of Contents

1.  Introduction
    1.1.  Benefits of This Work
    1.2.  Requirements Language
    1.3.  Outline
2.  Definitions
3.  The Verify Capability
    3.1.  Verify Capability
        3.1.1.  Overview
        3.1.2.  Dependencies
        3.1.3.  Capability Identifier
        3.1.4.  New Operations
            3.1.4.1.  <verify>
            3.1.4.2.  <cancel-verify>
            3.1.4.3.  <complete-verify>
            3.1.4.4.  <verifyStatus>
            3.1.4.5.  <verifyComplete>
        3.1.5.  Modifications to Existing Operations
4.  NETCONF Verify Framework
    4.1.  Test Modules
    4.2.  Use Cases
5.  Acknowledgements
6.  IANA Considerations
7.  Security Considerations
8.  References
    8.1.  Normative References
    8.2.  Informative References
Appendix A.  verify.yang Module
Appendix B.  Example ping.yang Module
§  Authors' Addresses

1.  Introduction

This document identifies enhancements to NETCONF capabilities to achieve a more robust model of configuration management for future IETF systems. Most network management systems which are required to provide a highly robust network service rely upon some form of out-of-band access for configuration management. This provides an alternative management entry into devices in the event that in-band access is unavailable due to, e.g., mis-configuration. However, not all network deployments can afford the luxury of alternative networks for management access to all networking devices, nor should this be necessary. Examples include Mobile Ad-Hoc Wireless Networks (MANETs) and other forms of Disruption Tolerant Networks (DTNs). All managed networks, as well, would benefit from a more robust and extensive configuration management capability from the IETF, e.g., to provide equivalent network reliability at reduced infrastructure costs. To accomplish this, the NETCONF protocol RFC 4741 (Enns, R., “NETCONF Configuration Protocol,” December 2006.) [RFC4741] requires extension of capabilities to define and manage active tests and assess success, i.e., Verification, (from both the client and the servers) involving server-side running configuration. This document defines the verify capability within NETCONF.

As an example, we envision a NETCONF client-server interaction model shown in the below figure. Here, the client issues a <commit> with the confirming option. As part of testing prior to issuing the confirming <commit> the client wishes to execute a set of verification tests from the server. It issues the new <verify> operation to manage this aspect of verification testing. The client passes a reference to the server indicating instances of specific pre-configured tests that define the verification test suite. The server executes these as part of the NETCONF <verify> testing process. Simultaneously, the client may also run a set of tests to gain confidence in the proposed configuration changes to the server. Once the server completes its test execution, it indicates success through notification messages. Once the client is comfortable with its own tests and those of the server, it issues the confirming <commit> to the server which forces the server to commit to the proposed configuration change.

  +------+                              +------+
  |Client|                              |Server|
  +------+                              +------+

         +------------------------------>
          Sets up <candidate> config

         +------------------------------>
          Sets up test control

---      +------------------------------>
 |        Sends <commit>
(set             - timeout
 timeout)        - confirm option
 |
 |
 |       +------------------------------>
 |        Sends <verify>
 |               - timeout
 |               - test-template:instanceIDs
 |
(running                                  (running
 client-side                               server-side tests)
 tests)                                   +--------+
 |                                                 |
 |                                                 |
 |                                        <--------+
 |                                        (server-side tests
 |                                         complete)
 |        <-----------------------------+
 |                 <verifyComplete = ok> notification
 |
 |
 |        +----------------------------->
 |         Sends <commit>
 |
 |
---

This, and other Use Cases, are discussed further in the 'Framework' section below.

NETCONF defines the term 'validation' as the set of checks performed on proposed configuration code up to the point that the server places it into its running-configuration.

We use the term 'verification' as the act of performing active tests against configuration code in the running-configuration on the server. (Note: strictly, verification probably should also cover the act of loading new configuration into the <running> configuration as this may fail, e.g., due to undocumented configuration constraints. However, here we focus on aspects of running active tests to measure network behavior as a form of verification testing.) Verification tests can be executed from either the NETCONF client or the NETCONF server, or from a NETCONF server(a) against running configuration code on a NETCONF server(b), or all combinations.

We define the new :verify capability as a set of stand-alone operations, notifications, and requirements on the definition of test modules for the purpose of managing verification testing on remote servers through standardized mechanisms. This allows for extensible verification testing of configuration across the base of IETF compliant devices. This leads to more resilient configuration management for operators manging multi-vendor networks of devices. This will promote future integrated network management capabilities as opposed to device management capabilities.

A more detailed presentation of the operation of the proposed :verify capability is given in the below figure. Here the client issues the <verify> operation indicating the timeout period, the set of tests which comprise the overall verification test suite, and the nature of the reporting from the server using the associated notification messages. The 'verifyStatus=true' indicates that the server should send intermediate status reports following completion of each test set in the suite. At the completion of the entire verification test suite, the server sends the final <verifyComplete> notification to the client.

The <verifyStatus> and <verifyComplete> notifications carry indications of test success or failure based upon pre-configured thresholds and metrics defined within the test module(s) resident on the server. Further, the <verify> operation carries test instance identifiers and switches for various types of reporting, i.e., summary or extended. In total, these place requirements on the definition of interoperable test modules to be developed in support of the :verify capability. We give an example of a ping.test module in Appendix B. Our intent is to define (in other associated documents) a set of connectivity, protocol and transaction test modules to fill out the utility of this verify capability.

  +------+                              +------+
  |Client|                              |Server|
  +------+                              +------+

         +------------------------------>
          Sends <verify>
                 - timeout
                 - test-template:instanceID=1,
                   test-template:instanceID=263,
                   test-template:instanceID=51
                 - verifyStatus=true
                 - extendedResults=false
---
 |                                        +-------+
 |                                                | tests 1
(set                                              |
 timeout)                                 <-------+
 |        <-----------------------------+
 |                 <verifyStatus = ok> notification
 |
 |                                        +-------+
 |                                                | tests 263
 |                                                |
 |                                        <-------+
 |        <-----------------------------+
 |                 <verifyStatus = ok> notification
 |
 |                                        +-------+
 |                                                | tests 51
 |                                                |
 |                                        <-------+
 |        <-----------------------------+
 |                 <verifyStatus = ok> notification
 |        <-----------------------------+
 |               <verifyComplete = ok> notification
 |
 |
 |
---

1.1.  Benefits of This Work

Our objective is to further develop a robust and resilient network configuration capability, building upon the improvements afforded by the NETCONF protocol and it's associated modeling language, YANG (Bjorklund, M., “YANG - A data modeling language for NETCONF,” June 2010.) [YANG].

The envisioned benefits of a standardized set of mechanisms and capabilities for verification testing include:

• Minimize faulty configuration and network disconnects,
• Provide for uniform methods for control, execution and reporting of verification testing in multi-vendor networks,
• Improve automation of extensive verification testing,
• Provide opportunity for device modelers to associate/recommend tests tied to specific configuration items, and
• Improve efficiency of coordinated network upgrades.

1.2.  Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 (Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels,” March 1997.) [RFC2119].

1.3.  Outline

In the remainder of this document we next give a set of definitions to be adhered to for the remainder of this discussion. We then provide a new :verify capability which achieves initial aspects of the Robust-NETCONF capabilities. We then examine in the Framework section the relationship of the :verify mechanisms, their relationship to test modules and definitions of metrics and success criteria. The 'Framework' section also covers use cases of the :verify capability. Then 'Acknowledgments' and 'IANA Considerations' are presented. A section on 'Security Considerations' is provided concluding the main body of the document.

Various appendices are provided to compliment the text of the main body. Prominent appendices are 'Appendix A: verify.yang' which presents the yang module for the :verify capability and 'Appendix B: ping.yang' which presents a simple example test module which complies with the requirements of the :verify capability.

2.  Definitions

In this section we provide definitions strictly adhered to throughout this document.

The NETCONF specification maintains the following terms:

• NETCONF Client (or client) - this is the management application responsible for the configuration management of network devices.
• NETCONF Server (or server) - this is the device being managed in the network.

We maintain the following distinction between Validation checks and Verification tests:

• Validation checks - checking non-running configuration code against a set of rules, constraints or other requirements. This addresses the total set of checks performed prior to the Server placing the code into its running-configuration.
• Verification tests - measuring behavior of running configuration code against a set of expectations or success criteria. This may be performed through active testing or passivie observation and comparison of results against expectations.
• Active measurements perform Verification while rule-based checks perform Validation.

We maintain the following definitions in the descriptions of the :verify capability:

• Verification test (or test set) - a set of identical measurements identified through a single instance identifier and defined in a test module which is pre-configured on the server.
• Verification test suite - the total set of verification tests identified by a set of instance identifiers passed to the server as parameters in the same <verify> message.

3.  The Verify Capability

In this section we describe a protocol development which we refer to as the :verify capability. The Yang module for this procedure, i.e., verify.yang, is listed in Appendix A below. An example test module, which complies with the requirements for test modules as spelled out in this document, is the ping.yang module in Appendix B below.

3.1.  Verify Capability

3.1.1.  Overview

The :verify capability provides a set of standard tools allowing the client to direct verifications tests from remote servers and to collect and uniformly interpret verification test reports related to the success or failure of the tests.

Note: this capability has several prerequisites, including support for <candidate> configuration and notifications.

Additionally, there will be secondary modules for definition of specific verification tests. We present our example in terms of a ping.yang module in Appendix B below. Other test modules will be developed in other documents.

So, a typical client/server interaction would hold:

1. Client sets up the <candidate> configuration on all relevant agents.
2. Client sets up all the relevant test control configuration needed for the verification tests on all relevant agents.
3. Client sends <verify> to all agents with parameters (timeout:seconds, test-template:instance-identifier,verifyStatus:true, extendedStatus:false), i.e.,
   

   ---

   <rpc xmlns="netconf-base" message-id="101">
     <verify xmlns="verify-module">
        <timeout>3600</timeout>
        <test-template xmlns:as="ping-module">
           /at:ping/at:pingEntry[at:pingControlIndex=21]
           /at:ping/at:pingEntry[at:pingControlIndex=42]
           /at:ping/at:pingEntry[at:pingControlIndex=48]
        </test-template>
        <verifyStatus>true</verifyStatus>
        <extendedStatus>false</extendedStatus>
     </verify>
   </rpc>
   

   Figure 3

   ---

4. Server returns <ok/>.
5. The Server runs the tests with the specified (e.g., pingControlEntry) configuration subtree.
6. For each completed test set, the server sends a report in a <verifyStatus> notification.
7. At the completion of the entire verification test suite, the server sends a summary report in a <verifyComplete> notification message.

The client can adjust the nature of the reporting through the 'verifyStatus' and the 'extendedResults' parameters of the &ly;verify> operation. The former determines whether or not <verifyStatus> notifications are sent from the server following the completion of each test set. The later determines whether or not the <verifyStatus> notifications carry raw test data (as defined within the test modules).

Further, the client can decide to immediately cancel all ongoing verification testing by issuing the <cancel-verify> operation. Or the client can decide to cut short the testing by issuing the <complete-verify> operation which instructs the server to complete only the in-progress test set and follow up with <verifyStatus> notification for that completed test set if the client had required this notification message and to wrap up the verification process by sending the <verifyComplete> notification.

3.1.2.  Dependencies

The :verify capability requires the existence of test modules resident on servers which comply with the following requirements:

• Must contain a 'list' keyed by a controlIndex which defines a verification test set.
• The 'list' must define an unequivocal means to determine the Boolean result (success or failure) of the specific verification test set. This information is passed in the <verifyStatus> notification.
• The 'list' must define a 'leaf-list' of raw results which may be passed to the client through the <verifyStatus> notification.

3.1.3.  Capability Identifier

The :verify capability is identified by the following capability string:

urn:ietf:params:netconf:capability:verify:1.0

3.1.4.  New Operations

3.1.4.1.  <verify>

The <verify> operation starts the verification tests on the server. The <verify> operation has four parameters:

• timeout - the timeout period associated with the verification test suite. If the timeout expires, the server should complete the in-progress test, send the <verifyStatus> notification for the test if the 'verifyStatus' parameter is set to 'true' and send the <verifyComplete> notification.
• test-template - this 'leaf-list' parameter uniquely identifies the verification test set to be performed by the server. Each verification test is identified by an 'instance-identifier' indexing a test definition on a test module resident on the server. Multiple test sets comprise a test suite.
• verifyStatus - this parameter is a switch which defaults to 'false' indicating no <verifyStatus> notifications are to be sent from the server to the client. When set to 'true' the server should send a <verifyStatus> notification following the completion of each verification test.
• extendedResults - this parameter is a switch which defaults to 'false' indicating no 'anyxml extendedResults' are to be sent in the <verifyStatus> notification. This parameter can only be set to 'true' if the 'verifyStatus' parameter is also set to 'true'. This indicates that the <verifyStatus> notifications should include the raw measurement results carried in the 'anyxml extendResults'.

3.1.4.2.  <cancel-verify>

The <cancel-verify> operation immediately cancels a verify test suite in progress on the server. The server terminates in-progress tests immediately and is not required to send any followup notification messages carrying test results.

3.1.4.3.  <complete-verify>

The <complete-verify> operation tells the server to complete the in-progress verification test and to send any required followup notifications carrying test results for the current test set and for the test suite.

3.1.4.4.  <verifyStatus>

The <verifyStatus> notification carries the results for each verification test set comprising the entire verification test suite. This notification may also carry raw extended results. This notification is optional and is requested explicitly by the client sending the 'verifyStatus=true' parameter in the <verify> operation.

3.1.4.5.  <verifyComplete>

The <verifyComplete> notification is mandatory (unless canceled by the <cancel-verify> operation) and carries a summary result covering the entire verification test suite.

3.1.5.  Modifications to Existing Operations

None.

4.  NETCONF Verify Framework

Note: should rewrite this section to discuss the relationship between :verify capability and supporting test.yang modules. Also discuss the way metrics and thresholds are defined in order to assess test 'pass/failure' decisions. This section should also contain a presentation of the use cases for the :verify capability.

4.1.  Test Modules

NOTE: Need to include a discussion of the test modules, their necessary requirements for interoperability and thoughts on the definition of metrics and thresholds.

4.2.  Use Cases

NOTE: Need to include a discussion of the use cases for the <verify> operation.

These include:

• Used within a <commit> operation with the 'confirmed' parameter.
• Used to verify the configuration of server(a) following the re-configuration of server(b).
• Used to verify the <running> configuration prior to copying it into the <startup> configuration.

5.  Acknowledgements

The authors wish to thank the many useful suggestions by and discussions with Martin Bjorklund on this capability proposal.

6.  IANA Considerations

This memo includes no request to IANA.

All drafts are required to have an IANA considerations section (see the update of RFC 2434 (Narten, T. and H. Alvestrand, “Guidelines for Writing an IANA Considerations Section in RFCs,” March 2008.) [I‑D.narten‑iana‑considerations‑rfc2434bis] for a guide). If the draft does not require IANA to do anything, the section contains an explicit statement that this is the case (as above). If there are no requirements for IANA, the section will be removed during conversion into an RFC by the RFC Editor.

7.  Security Considerations

This section presents the required security considerations for all IETF protocols and capabilities. This section was developed following guidelines within RFC 3552 (Rescorla, E. and B. Korver, “Guidelines for Writing RFC Text on Security Considerations,” July 2003.) [RFC3552].

This section addresses the security concerns and objectives for the :verify capability within NETCONF. (NOTE: This section is currently TBD.)

Security issues related to the :verify capability should address issues specific to the proposed NETCONF operations. They should also address security issues associated with the development of associated test modules for the purpose of running verification tests. Here is an initial list of potential considerations:

• Verification requires server-side tests that require that packets to be injected into the network for the purpose of measuring some performance characteristics. As such, associated test modules will contain sensitive network and application data; e.g., user IDs and passwords. Further, if security is compromised, this capability could provide a source for denial-of-service, and potential other, attacks.
• The configuration of verification tests may require passing sensitive network information. For this reason, this configuration information should be encrypted prior to transport over the network.
• Some test attributes configure username and password information for some application-level protocols as indicated above. Access to these attributes may provide unauthorized use of resources.
• Some test attributes configure the size and rate of traffic flows for the purpose of performance measurements. Access to these attributes may exacerbate the use of this capability in denial-of-service attacks. It is recommended that test modules define a maximum packet rate on the device and to indicate this rate. Other objects that control aspects of the test packets related to packet size and rate are will exist in test modules and bounds on these should be set.
• Test module objects will exist which set the source and destination addresses on the packet headers. The server should not allow the setting of source addresses on the test packets other than those that are administratively configured onto the server.

8.  References

8.1. Normative References

8.2. Informative References

Appendix A.  verify.yang Module

In this appendix we list the verify.yang model for use in conjunction with the robust-netconf capabilities.

Note: this capability has several prerequisites, including support for notifications and recommended support for the confirmed-commit: capability.

=========Contents of "verify.yang"==================

module verify {

      namespace
        "file:///draft-cole-netconf-verify-00.txt";

      prefix "ver";

      organization  "IETF";

      contact "[add contact info here].";

      description
        "NETCONF verify procedure.";

      revision 2010-01-21 {
          description  "Initial version.";
      }

      rpc verify {
          description
            "The verify procedure is started by
             invoking this operation.

               * A verify proceedure is comprised of
                 multiple verification test sets, each
                 indicated by an instance-identifier
                 within the 'test-template leaf-list'
                 of the <verify> operation.  Multiple
                 test sets comprise a test suite.

               * the agent will cancel the verify
                 procedure if the <cancel-verify>
                 operation is invoked.

               * the agent will complete the current
                 verification test set and generate the
                 <verifyStatus> and <verifyComplete>
                 notifications if the <cancel-verify>
                 operation is invoked.

               * the agent will start, monitor, and report
                 the verification test(s) during the time
                 interval after this operation, and before
                 the 'timeout' interval has expired.

               * the agent will generate the <verifyStatus>
                 notification for each verification test set specified
                 in the 'test-template leaf-list', indicating the
                 result of each verification test set.

               * the agent will generate the <verifyComplete>
                 notification at the completion of the entire
                 test suite, indicating the
                 final verify procedure status.

               * the definition of this capability places requirements
                 on the development of test.yang modules to provide
                 the following set of features:
                     - test sets identified by 'instanceId's,
                     - test suites identified by the collection of
                       instanceIds,
                     - test suites unambiguously identify:
                       metric and target, Boolean
                       (pass/fail) threshold, (optional) raw data
                       capability.
                 These requirements are defined in section 3.1.2.

               * <verifyStatus> is sent follow each verification test
                 and indicates pass/fail status of test based upon
                 (metric, target, threshold) triplet.  It may also
                 carry raw data values from the 'rawResults' node
                 carried within the <verifyStatus>'s
                 'anyxml extendedStatus'.
            ";

          input {
              leaf timeout {
                  description
                    "The time interval the agent has to perform
                     the verify operation.  If not complete at
                     timeout, then server must issue <verifyStatus>
                     indicating partial test results and that
                     verification tests are being terminated.";
                  type uint32;
                  units seconds;
                  default 600;
              }

              leaf-list test-template {
                  description
                    "Identifies a verification test control entry
                     or entries for the agent to use for the
                     verification procedure.

                     The verification test control entry must conform
                     to the requirements specified in section 3.1.2,
                     and the agent must be capable of starting,
                     monitoring, and reporting the results of
                     the verification test, as required.

                     The agent will also generate the
                     <verifyStatus> notification,
                     as specified for each verification test st
                     control entry indicated by this parameter.";
                  ordered-by user;
                  type instance-identifier;
                  min-elements 1;
              }

              leaf verifyStatus {
                  description
                    "A switch indicating the use of the
                     <verifyStatus notification.  If 'false'
                     the client does not want to receive
                     the <verifyStatus> notification
                     associated with each verification test set
                     in the verification test suite.  Instead,
                     it only wants to receive the final
                     <verifyComplete> notification which
                     contains a summarized pass/fail result
                     for the verification test suite.

                     If 'true', then the client is requesting
                     that the server generates <verifyStatus>
                     notifications for each verification test set
                     in the verification test suite.";
                  type boolean;
                  default false;
              }

              leaf extendedResults {
                  description
                    "A switch indicating that the client is
                     requesting raw test results through
                     the 'anyxml extendedResults'.  This
                     defaults to 'false'.

                     This can only be set to 'true' if the
                     proceeding 'verifyStatus' leaf is set
                     to 'true'.  Else, the server should
                     generate an error response to this
                     request.";
                  type boolean;
                  default false;
              }

          }
      }



      rpc cancel-verify {
          description
            "Cancel a verify procedure already in progress.

             If no verify procedure is currently in
             progress, then an 'operation-failed' error is
             generated, and the value 'no-verify'
             is used for the error-app-tag field.

             If the verify procedure in progress
             cannot be canceled for any reason, then an
             'operation-failed' error is returned, and
             the value 'cancel-failed' is used in the
             error-app-tag field.

             If any verification test sets associated with this
             verify procedure are still in progress,
             they will be canceled by this operation.

             If the verify procedure in progress
             is canceled, then the agent will return <ok/>.
            ";
      }

      rpc complete-verify {
          description
            "Complete a verify procedure already in progress.

             If no verify procedure is currently in
             progress, then an 'operation-failed' error is
             generated, and the value 'no-verify'
             is used for the error-app-tag field.

             If the verify procedure in progress
             cannot be completed for any reason, then an
             'operation-failed' error is returned, and
             the value 'complete-failed' is used in the
             error-app-tag field.

             If any verification test sets associated with
             this verify test suite are still in progress,
             they will be canceled by this operation
             following the completion of the current
             test set.

             If the verify procedure in progress
             is completed, then the agent will return <ok/>.
            ";
      }

      notification verifyStatus {
          description
            "Contains the current or final status of
             a verification test being invoked on behalf
             of the current verify procedure.";

          list eachTest {
              key "testIdentifier";

              leaf testIdentifier {
                  description
                    "Indicates which verification test this
                     status report is associated with.
                     This value will identify the same node
                     as specified in a 'test-template'
                     parameter instance provided in the
                     <verify> operation.";
                  type instance-identifier;
                  mandatory true;
              }

              leaf statusType {
                  description
                    "Indicates the type of status report that
                     this notification contains.";
                  type enumeration {
                      enum partial {
                          description
                            "Indicates this is a partial status result
                             for this verification test
                             which is still in progress.";
                      }
                      enum final {
                          description
                            "Indicates this is the final status result
                             and this verification test which completed
                             or canceled.";
                      }
                  }
                  mandatory true;
              }

              leaf status {
                  description
                    "Indicates the NETCONF error-tag value most
                     closely associated with the test status.
                     The string 'ok' is used to indicate that
                     the pass threshold for the test has been
                     exceeded.";
                  type string;
                  reference "RFC 4741bis, Appendix A";
                  mandatory true;
              }

              anyxml extendedStatus {
                  description
                    "Indicates verification test-specific status data.
                     The requirements for verification tests
                     (section 3.1.2) describes how the semantics
                     of this structure are determined.";
              }
          }
      }

      notification verifyComplete {
          description
            "Contains the final status of the
             current verify test suite.";

          leaf status {
              description
                "Indicates the NETCONF error-tag value most
                 closely associated with the test status.
                 The string 'ok' is used to indicate that
                 the pass thresholds were exceeded for
                 all tests in the verification test suite.";
              type string;
              reference "RFC 4741bis, Appendix A";
              mandatory true;
          }
      }

  }

Appendix B.  Example ping.yang Module

In this appendix we list an example ping.yang model for use in conjunction with the :verify capability.

Specifically, the <verify> operation passes the instance-identifiers in the 'test-template' parameter. Each instance-identifier identifies a specific ping test. The <verify> operation manages the identification, execution and reporting of multiple tests within a single verification test procedure.

<rpc xmlns="netconf-base" message-id="101">
  <verify xmlns="verify-module">
     <timeout>3600</timeout>
     <test-template xmlns:as="ping-module">
        /at:ping/at:pingEntry[at:pingControlIndex=21]
        /at:ping/at:pingEntry[at:pingControlIndex=42]
        /at:ping/at:pingEntry[at:pingControlIndex=48]
     </test-template>
     <verifyStatus>true</verifyStatus>
     <extendedStatus>false</extendedStatus>
  </verify>
</rpc>

=========Contents of "ping.yang"==================

module ping {

       namespace "unassigned";
       prefix "at";

       import ietf-yang-types { prefix yang; }
       import ietf-inet-types { prefix inet; }


       organization "IETF";

       contact
           "Andy Bierman
            InterWorking Labs
            EMail: andyb@iwl.com

            Robert G. Cole
            US Army CERDEC
            Email: robert.g.cole@us.army.mil

            Dan Romascanu
            Avaya
            Email:dromasca@avaya.com";

            description
                "The module for entities implementing
                 the ping test.";

            revision 2010-01-27 {
                description "Second revision:
                    Added 'pingEntry' list to hold multiple
                    pre-defined test specifications.  Added
                    (metric, target, threshold) triplet
                    for pass/fail determination.  Added
                    raw data collection and reporting
                    (optional).";
            }


            leaf test-reference {
                type string;
                config false;
                description "URL for the definition of this
                             test";
            }

            list pingEntry {
                key "pingControlIndex";
                config true;

                leaf pingControlIndex {
                    type uint32;
                    description
                        "Identifies the specific control table
                         row of the ping test template to be
                         executed, which represents the
                         verification tests to be performed
                         on the device as part of the verified
                         commit operation.";

                }

                leaf dstAddr {
                    type inet:ip-address;
                    description
                        "Identifies the destination address in
                         the packet header of the ping message.";
                }

                leaf srcAddr {
                    type inet:ip-address;
                    description
                        "Identifies the source address in the
                         packet header of the ping message.";
                }

                leaf spacing {
                    type uint32;
                    description
                        "The number of seconds between sending
                         subsequent ping packets.";
                }

                leaf startTime {
                    type yang:date-and-time;
                    config false;
                    description
                        "The time the first ping packet
                         was sent for the previous test.
                         This is set each time the test
                         is initiated from a client.  When this
                         value is reset, the value of the
                         'result' node is set to
                         'indeterminant' and the value of the
                         'received' node is set to zero.";

                }

                leaf number {
                    type uint32;
                    description
                        "The number of ping packets to be sent.";
                }

                leaf metric {
                    type enumeration;
                        enum loss {
                            description
                               "Holds the indication of whether
                                the transaction was successful (1)
                                or failed (0).";
                        }
                        enum delay {
                            description
                               "Holds the number of milliseconds
                                for the successful transaction
                                or '0' if the transaction failed.";
                        }
                        enum throughput {
                            description
                               "Holds the measured throughput
                                in units of bytes/millisecond for
                                the transaction if successful
                                or '0' if failed.";
                        }
                    default "loss";
                    description
                        "The metric tracked by this specific test.
                         These values are held on the rawResults
                         if the specific test indicates storage
                         of raw data values.";
                }

                leaf target {
                    type uint32;
                    description
                        "The preformance target for each transaction
                         measurement.  A measured transaction is deemed
                         successful if its measured 'metric' value
                         falls within the limits defined by this
                         'target'.  E.g.,
                             if 'metric = loss', then 'target' must
                                equal '1' indicating success if repsonse
                                recieved.
                             if 'metric = delay', then responses
                                received within 'target' milliseconds
                                are counted as successful.
                             if 'metric = throughput', then responses
                                recieved with throughputs greater than
                                'target' are counted as successful.

                         The target value carries the
                         units defined by the 'metric', i.e.,
                             unitless if 'metric = loss',
                             milliseconds if 'metric = delay',
                             bytes/milliseconds if
                             'metric = throughput'.

                         The server counts the number of transaction
                         measurements that are deemed successful.  This
                         count is compared against 'threshold' to
                         determine overall success or failure of the
                         test.";
                    default "1";
                }

                leaf threshold {
                    type uint32;
                    description
                        "The threshold value that determines the
                         pass/fail status reported to the client
                         by this server in the 'verifyStatus'
                         notification.";
                }

                leaf received {
                    type uint32;
                    config false;
                    description
                        "The number of successful
                         ping transactions received during
                         the previous test.  This value
                         is initialized to zero prior to
                         the instantiation of the test
                         and is incremented by one for
                         each received ping packet.  This
                         is set each time the test is
                         initiated from a client.";
                }

                leaf result {
                    type enumeration {
                        enum indeterminant{
                            description
                               "Set to 'indeterminant' upon
                                the initiation of a test.";
                        }
                        enum success{
                            description
                               "Set to 'success' if the
                                number of successful pings
                                exceeded the 'threshold'.";
                        }
                        enum failure{
                            description
                               "Set to 'failure' if the
                                number of successful pings is less
                                than or equal to the 'threshold'.";
                        }
                    config false;
                    description
                        "The result of the previous test.";
                }

                leaf rawResultCollection {
                    type enumeration;
                        enum off {
                            description
                               "Indicates that the server will
                                not store the raw transaction
                                measurement values of type indicated
                                by metric.";
                        }
                        enum on {
                            description
                               "Indicates that the server will
                                store the raw transaction
                                measurement values of type indicated
                                by metric.  Further, these raw
                                measurement values will be passed
                                to the client throught 'verifyStatus'
                                notification's 'extendedStatus'
                                node.";
                        }
                    config true;
                    default "off";
                    description
                        "A switch to turn ON or OFF the raw
                         data collection and notification.";
                }

                leaf-list rawResults {
                    description
                      "Holds the raw metric value for each transaction
                       successfully recorded as part of the specific
                       test.  The units used for these values conform
                       to the units defined with the 'metric' measured.

                       Upon completion of this specific test, the server
                       passes this measurement data to the requesting
                       client through the 'verifyStatus' notification's
                       'anyxml extendedStatus'.";
                    ordered-by system;
                    type uint32;
                    config false;
                    min-elements 1;
                }


            }

   }

Authors' Addresses