[Docs] [txt|pdf|xml] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: (draft-chairs-netmod-opstate-reqs) 00 01 02 03 04 Draft is active
In: Waiting_for_AD_Go-Ahead
NETMOD Working Group                                           K. Watsen
Internet-Draft                                          Juniper Networks
Intended status: Informational                                 T. Nadeau
Expires: July 25, 2016                                  Brocade Networks
                                                        January 22, 2016


Terminology and Requirements for Enhanced Handling of Operational State
                   draft-ietf-netmod-opstate-reqs-04

Abstract

   This document primarily regards the difference between the intended
   configuration and the applied configuration of a device and how
   intended and applied configuration relate to the operational state of
   a device.  This document defines requirements for the applied
   configuration's data model and its values, as well as for enabling a
   client to know when a configuration has been fully applied or not,
   how to access operational state, and how to relate intended
   configuration nodes to applied configuration and derived state nodes.

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 July 25, 2016.

Copyright Notice

   Copyright (c) 2016 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



Watsen & Nadeau           Expires July 25, 2016                 [Page 1]


Internet-DraftTerms and Reqs for OpState Enhanced Handling  January 2016


   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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Requirements  . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   This document primarily regards the difference between the intended
   configuration and the applied configuration of a device and how
   intended and applied configuration relate to the operational state of
   a device.  This document defines requirements for the applied
   configuration's data model and its values, as well as for enabling a
   client to know when a configuration has been fully applied or not,
   how to access operational state, and how to relate intended
   configuration nodes to applied configuration and derived state nodes.

2.  Terminology

   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 [RFC2119].

   The term "client" is used throughout this document to refer to what
   is many times known as the "application" or "network management
   system".  This definition is intended to be consistent with the term
   "client" defined in [RFC6241], Section 1.1, but independent of any
   association to a particular protocol.

   The term "server" is used throughout this document to refer to what
   is many times known as the "device", "system", or "network element".
   This definition is intended to be consistent with the term "server"
   defined in [RFC6241], Section 1.1, but independent of any association
   to a particular protocol.

   This document defines the following terms:



Watsen & Nadeau           Expires July 25, 2016                 [Page 2]


Internet-DraftTerms and Reqs for OpState Enhanced Handling  January 2016


   Applied Configuration:  This data represents the configuration state
       that the server is actually in.  That is, the configuration state
       which is currently being used by server components (e.g., control
       plane daemons, operating system kernels, line cards).  With
       respect to NETCONF architecture, the applied configuration
       resides in the "system software component" box listed on page 15
       of [RFC6244]

          NOTE: The server's ability to report applied configuration
          accurately may be limited in some cases, such as when the
          configuration goes through an intermediate layer without an
          ability to inspect the lower layer.

   Asynchronous Configuration Operation:  A configuration request to
       update the running configuration of a server that is applied
       asynchronously with respect to the client request.  The server
       MUST update its intended configuration before replying to the
       client indicating whether the request will be processed.  This
       reply to the client only indicates whether there are any errors
       in the original request.  The server's applied configuration
       state is updated after the configuration change has been fully
       effected to all impacted components in the server.

   Derived State:  This data represents information which is generated
       as part of the server's own interactions.  For example, derived
       state may consist of the results of protocol interactions (the
       negotiated duplex state of an Ethernet link), statistics (such as
       message queue depth), or counters (such as packet input or output
       bytes).

   Intended Configuration:  This data represents the configuration state
       that the network operator intends the server to be in, and that
       has been accepted by the server as valid configuration.  With
       respect to NETCONF architecture, the intended configuration is
       captured by the "config database" box listed on page 15 of
       [RFC6244]

   Operational State:  Operational State is the current state of the
       system as known to the various components of the system (e.g.,
       control plane daemons, operating system kernels, line cards).
       The operational state includes both applied configuration and
       derived state.

   Synchronous Configuration Operation:  A configuration request to
       update the running configuration of a server that is applied
       synchronously with respect to the client request (i.e. a blocking
       call).  The server MUST fully attempt to apply the configuration
       change to all impacted components in the server, updating both



Watsen & Nadeau           Expires July 25, 2016                 [Page 3]


Internet-DraftTerms and Reqs for OpState Enhanced Handling  January 2016


       the server's intended and applied configuration, before replying
       to the client.  The reply to the client indicates whether there
       are any errors in the request or errors from applying the
       configuration change.

3.  Requirements

   1.  Ability to interact with both intended and applied configuration

       A.  The ability to ask the operational components of a server
           (e.g., line cards) for the configuration that they are
           currently using.  This is the applied configuration.

       B.  Applied configuration is read-only

       C.  The data model for the applied configuration is the same as
           the data model for the intended configuration (same leaves)

       D.  When a configuration change for any intended configuration
           node has been successfully applied to the server (e.g. not
           failed, nor deferred due to absent hardware) then the
           existence and value of the corresponding applied
           configuration node must match the intended configuration
           node.

   2.  Support for both synchronous and asynchronous configuration
       operations

       A.  A server MUST support only synchronous configuration
           operations, or only asynchronous configuration operations, or
           both synchronous and asynchronous configuration operations on
           a client-specified per-operation basis.

       B.  Servers that support asynchronous configuration operations
           MUST provide a mechanism to notify the client when a request
           has completed processing.  The notification MUST indicate
           whether the intended config is now fully applied or if there
           were any errors from applying the configuration change.

       C.  Servers that support asynchronous configuration operations
           SHOULD also provide a verify operation that a client can
           request from the server to return information regarding the
           difference between the intended and applied configurations.

       D.  The configuration protocol MUST specify how configuration
           errors are handled.  Errors SHOULD be handled by semantics
           similar to NETCONF's error-options for the <edit-config>
           operation (stop-on-error, continue-on-error, rollback-on-



Watsen & Nadeau           Expires July 25, 2016                 [Page 4]


Internet-DraftTerms and Reqs for OpState Enhanced Handling  January 2016


           error), as described in Section 7.2 in [RFC6241], but
           extended to incorporate both the intended and applied
           configurations.  Support for "rollback on error" semantics
           SHOULD be provided.

   3.  Separation of the applied configuration and derived state aspects
       of operational state; ability to retrieve them independently and
       together

       A.  Be able to retrieve only the applied configuration aspects of
           operational state

       B.  Be able to retrieve only the derived state aspects of
           operational state

       C.  Be able to retrieve both the applied configuration and
           derived state aspects of operational state together

   4.  Ability to relate configuration with its corresponding
       operational state

       A.  Ability to relate intended config nodes to corresponding
           applied config nodes

       B.  Ability to relate intended config nodes to associated derived
           state nodes

       C.  The relationships need to be programmatically consumable

   5.  Backwards compatibility

       A.  It MUST be possible to upgrade a server to one that supports
           the solution without breaking existing/legacy clients.

       B.  It MUST be possible for a client that has been coded to
           support the solution to interoperate appropriately with
           existing/legacy servers.

4.  Security Considerations

   It is understood that the intended and applied configurations will
   differ while synchronization is in progress.  During the
   synchronization process, the server will be in an inconsistent state
   from the client's perspective.  Implementations need to take care to
   ensure that this process minimizes gaps in the application of
   security policy (e.g., replacing a firewall policy in a single step).
   Implementations additionally need to ensure that any gaps in security




Watsen & Nadeau           Expires July 25, 2016                 [Page 5]


Internet-DraftTerms and Reqs for OpState Enhanced Handling  January 2016


   policies are not dependent on external input that an attacker might
   be able to control or prevent access to.

5.  IANA Considerations

   None

6.  Acknowledgements

   The authors would like to thank the following for contributing to
   this document (in alphabetic order): Acee Lindem, Andy Bierman, Anees
   Shaikh, Benoit Claise, Carl Moberg, Dan Romascanu, Dean Bogdanovic,
   Gert Grammel, Jason Sterne, Jonathan Hansford, Juergen Schoenwaelder,
   Lou Berger, Mahesh Jethanandani, Martin Bjorklund, Phil Shafer, Randy
   Presuhn, Rob Shakir, Robert Wilton.

7.  References

7.1.  Normative References

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

7.2.  Informative References

   [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,
              <http://www.rfc-editor.org/info/rfc6241>.

   [RFC6244]  Shafer, P., "An Architecture for Network Management Using
              NETCONF and YANG", RFC 6244, DOI 10.17487/RFC6244, June
              2011, <http://www.rfc-editor.org/info/rfc6244>.

Authors' Addresses

   Kent Watsen
   Juniper Networks

   EMail: kwatsen@juniper.net


   Thomas Nadeau
   Brocade Networks

   EMail: tnadeau@lucidvision.com



Watsen & Nadeau           Expires July 25, 2016                 [Page 6]


Html markup produced by rfcmarkup 1.124, available from https://tools.ietf.org/tools/rfcmarkup/