[Docs] [txt|pdf|xml|html] [Tracker] [Email] [Nits]

Versions: 00 01 02 03

I2RS working group                                              S. Hares
Internet-Draft                                                    Huawei
Intended status: Standards Track                          March 15, 2016
Expires: September 16, 2016


                         I2RS protocol strawman
               draft-hares-i2rs-protocol-strawman-00.txt

Abstract

   This document provides a strawman proposal for the I2RS protocol
   covering the ephemeral data store and data flow requirements not
   covered by i2rs publication/subscription service or traceability.  It
   also proposes additions to YANG for the ephemeral data store and for
   additional data flow requirements.  It proposes additions to the
   NETCONF and RESTCONF for these additions.  Future versions of this
   document will propose changes to support the I2RS protocol security
   requirements.

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 September 16, 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
   to this document.  Code Components extracted from this document must



Hares                  Expires September 16, 2016               [Page 1]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Ephemeral Changes . . . . . . . . . . . . . . . . . . . .   4
     1.2.  Data Flow Changes . . . . . . . . . . . . . . . . . . . .   4
   2.  Definitions Related to Ephemeral Configuration  . . . . . . .   5
   3.  Definition of ephemeral datastore for NETCONF/RESTCONF  . . .   6
   4.  Error handling  . . . . . . . . . . . . . . . . . . . . . . .   9
     4.1.  Syntax validation . . . . . . . . . . . . . . . . . . . .  10
     4.2.  Referential validation  . . . . . . . . . . . . . . . . .  10
     4.3.  Grouping and Error handling . . . . . . . . . . . . . . .  11
       4.3.1.  Initial Support of Parital Writes . . . . . . . . . .  11
       4.3.2.  Future Scope of multiple message writes . . . . . . .  11
     4.4.  priority preemption . . . . . . . . . . . . . . . . . . .  12
       4.4.1.  Andy Bierman Priority Comment . . . . . . . . . . . .  12
   5.  transport protocol  . . . . . . . . . . . . . . . . . . . . .  13
     5.1.  Secure Protocols  . . . . . . . . . . . . . . . . . . . .  13
     5.2.  Insecure Protocol . . . . . . . . . . . . . . . . . . . .  13
   6.  Yang Library Use by Ephemeral . . . . . . . . . . . . . . . .  13
   7.  Simple Thermostat Model . . . . . . . . . . . . . . . . . . .  14
     7.1.  Yang changes  . . . . . . . . . . . . . . . . . . . . . .  15
     7.2.  RESTCONF sequence . . . . . . . . . . . . . . . . . . . .  16
     7.3.  NETCONF messages  . . . . . . . . . . . . . . . . . . . .  16
   8.  NETCONF protocol extensions for the ephemeral datastore . . .  17
     8.1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . .  17
     8.2.  Dependencies  . . . . . . . . . . . . . . . . . . . . . .  18
     8.3.  Capability identifier . . . . . . . . . . . . . . . . . .  18
     8.4.  New Operations  . . . . . . . . . . . . . . . . . . . . .  19
       8.4.1.  link-ephemeral  . . . . . . . . . . . . . . . . . . .  19
       8.4.2.  Bulk-Write  . . . . . . . . . . . . . . . . . . . . .  19
     8.5.  Modification to existing operations . . . . . . . . . . .  19
       8.5.1.  <get-config>  . . . . . . . . . . . . . . . . . . . .  19
       8.5.2.  <edit-config> . . . . . . . . . . . . . . . . . . . .  20
       8.5.3.  <copy-config> . . . . . . . . . . . . . . . . . . . .  21
       8.5.4.  <delete-config> . . . . . . . . . . . . . . . . . . .  21
       8.5.5.  <lock> and <unlock> . . . . . . . . . . . . . . . . .  21
       8.5.6.  <get> . . . . . . . . . . . . . . . . . . . . . . . .  22
       8.5.7.  <close-session> and <kill-session>  . . . . . . . . .  22
     8.6.  Interactions with Capabilities  . . . . . . . . . . . . .  22
       8.6.1.  writable-running and candidate datastore  . . . . . .  22
       8.6.2.  confirmed commmit . . . . . . . . . . . . . . . . . .  22
       8.6.3.  rollback-on-error . . . . . . . . . . . . . . . . . .  22
       8.6.4.  validate  . . . . . . . . . . . . . . . . . . . . . .  22
       8.6.5.  Distinct Startup Capability . . . . . . . . . . . . .  23



Hares                  Expires September 16, 2016               [Page 2]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


       8.6.6.  URL capability and XPATH capability . . . . . . . . .  23
   9.  RESTCONF protocol extensions for the ephemeral datastore  . .  23
     9.1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . .  23
     9.2.  Dependencies  . . . . . . . . . . . . . . . . . . . . . .  23
     9.3.  Capability identifier . . . . . . . . . . . . . . . . . .  24
     9.4.  New Operations  . . . . . . . . . . . . . . . . . . . . .  24
     9.5.  modification to data resources  . . . . . . . . . . . . .  24
     9.6.  Modification to existing operations . . . . . . . . . . .  24
       9.6.1.  OPTIONS changes . . . . . . . . . . . . . . . . . . .  24
       9.6.2.  HEAD changes  . . . . . . . . . . . . . . . . . . . .  24
       9.6.3.  GET changes . . . . . . . . . . . . . . . . . . . . .  24
       9.6.4.  POST changes  . . . . . . . . . . . . . . . . . . . .  25
       9.6.5.  PUT changes . . . . . . . . . . . . . . . . . . . . .  25
       9.6.6.  PATCH changes . . . . . . . . . . . . . . . . . . . .  25
       9.6.7.  DELETE changes  . . . . . . . . . . . . . . . . . . .  25
       9.6.8.  Query Parameters  . . . . . . . . . . . . . . . . . .  25
     9.7.  Interactions with Notifications . . . . . . . . . . . . .  25
     9.8.  Interactions with Error Reporting . . . . . . . . . . . .  25
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  26
   11. Security Considerations . . . . . . . . . . . . . . . . . . .  26
   12. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  26
   13. Major Contributors  . . . . . . . . . . . . . . . . . . . . .  27
   14. References  . . . . . . . . . . . . . . . . . . . . . . . . .  27
     14.1.  Normative References:  . . . . . . . . . . . . . . . . .  27
     14.2.  Informative References . . . . . . . . . . . . . . . . .  29
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  29

1.  Introduction

   This documents is a strawman for I2RS higher level protocol.  The
   I2RS protocol is a higher level protocol is comprised of a set
   existing protocols which have been extended to work together to
   support a new interface to the routing system.

   This draft is input to a NETCONF review and design team.

   This strawman proposal for the I2RS protocol covers the ephemeral
   data store and data flow requirements not covered by I2RS
   publication/subscription service or traceability.  It also proposes
   additions to YANG for the ephemeral data store and for these
   additional data flow requirements.  It also proposes extensions to
   NETCONF and RESTCONF to support ephemeral state and I2RS.

   draft-hares-i2rs-protocol-strawman-examples (pending) provides
   examples of this strawman protocol use for I2RS.  This draft uses a
   simple thermostat model to illustrate commands.





Hares                  Expires September 16, 2016               [Page 3]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


1.1.  Ephemeral Changes

   This document proposes additions to support ephemeral state in the
   datastores supported by NETCONF and RESTCONF, and in the YANG modules
   that define these data stores.  The requirements for the I2RS
   ephemeral state are covered in [I-D.ietf-i2rs-ephemeral-state]

   This draft provides suggests the following additions to support the
   I2RS ephemeral state:

   o  Yang ephemeral statement,

   o  NETCONF ([RFC6241]) protocol extensions for the ephemeral data
      store,

   o  RESTCONF ([I-D.ietf-netconf-restconf]) protocol extensions for the
      ephemeral data store

1.2.  Data Flow Changes

   This document proposes additions to support data flows from different
   data models for large data flows, traffic monitoring, actions and OAM
   interaction, and flows during outages or attacks.  The requirements
   for these changes are define in [I-D.hares-i2rs-dataflow-req].

   Most large data flows will be handled utilizing the publication/
   subscription service define in the I2RS publication/subscription
   service requirements specified in
   [I-D.ietf-i2rs-pub-sub-requirements].  Extensions to NETCONF to
   support a push publication/subscription service have been defined in
   [I-D.ietf-netconf-yang-push].  This document does not propose a pull
   publication/subscription (pull pub-sub) service for the first set of
   component protocols for the I2RS higher level protocol.  If
   deployments require the pull pub-sub service, then an expansion of
   the push service can provide one mechanism.

   This document does provide support for the I2RS protocol to:

      Support large data transfers in a data agnostic format (DF-REQ-02)
      supporting transfers of data in any format (E.g.  XML, JSON, MTL,
      protobuf, ASCII) over any transport (DF-REQ-03).

      Support the use of IPFIX as a component protocol to send traffic
      monitoring data or any type of large data flow from I2RS agent to
      I2RS client (DF-REQ-04),

      Support exporting traffic statistics for filter-based policies
      usage (BGP-FS, I2RS FB-FIB, policy routing), IPPM, SFLOW and other



Hares                  Expires September 16, 2016               [Page 4]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


      traffic statistics using either yang models or IPFIX template
      formats over any data encapsulation format over any transport (DF-
      REQ-05).

2.  Definitions Related to Ephemeral Configuration

   Currently the configuration systems managed by NETCONF ([RFC6241]) or
   RESTCONF ([I-D.ietf-netconf-restconf]) have three types of
   configuration: candidate, running, and startup running under the
   config=true flag.

   o  The candidate receives configuration changes from NETCONF/
      RESTCONF.

   o  The running configuration is the configuration currently operating
      on a devices

   o  The start-up configuration is the configuration that survives a
      reboot.

   The config=false flag has operational data which exists alongside the
   config=true data.  However, at this point there is no datastored
   defined for configuration false.

    ...........      ...........     ...........
    :Candidate : --> : running : --> :start-up  :
    ...........      ...........     ...........

    config true
    ---------------------------------------------
    config false


    Figure 1

   The [I-D.ietf-netmod-opstate-reqs] defines new terms to clarify how
   this works.  In reality, the running configuration becomes the
   intended configuration that is intended to be loaded into a device.
   The loading of the update into the system can be either asynchronous
   or synchronous.  In the asynchronous case, the netconf server
   responds to the client after the intended has been updated, but the
   applied configuration is only updated later when the configuration
   change has full impacted all components on the device.  The
   synchronous configuration operation occurs when both the intent
   configuration has been updated and the actual configuration has been
   loaded after resolving the necessary things to load in a box.





Hares                  Expires September 16, 2016               [Page 5]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


   This document will use the terms defined in
   [I-D.ietf-netmod-opstate-reqs].

    ...........      ...........     ...........
    :Candidate : --> : running : --> :start-up :
    ...........      ......||...     ...........
                           ||
                    =======||========
                    | Intended      |
                    | configuration |
                    ======||=========
    config true           ||
    ----------------------||-------------------
    config false          ||
         +----------------||------+
         | operational    ||      |
         | state          ||      |
         |       =========||==    |
         |       | Applied   |    |
         |       | config    |    |
         |       =============    |
         |       _____________    |
         |       |  derived  |    |
         |       |  state    |    |
         |       |___________|    |
         +------------------------+
    Figure 2

3.  Definition of ephemeral datastore for NETCONF/RESTCONF

   This section describes the properties of the ephemeral datastore.
   The ephemeral datastore is not unique to I2RS.  This approach to the
   ephemeral datastore is a panes-of-glass model.  This definition of
   I2RS does not support caching in the I2RS Agents.  Future I2RS work
   may reconsidered supporting caching.
















Hares                  Expires September 16, 2016               [Page 6]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


    ............    ...............   ...........
    :Candidate :-->: running      :-->:start-up :
    ............    ..|............   ...........
    :ephemeral :      | :ephemeral:
    : candidate:      | : running :
    ............      | ........|..
                      |         |
                      |         |
           ===========|=========|==========
           | Intended         Ephemeral   |
           | configuration   Intended     |
           |                 Configuration|
           |===========||==================
                       ||
    config true        ||
    -------------------||----------------------
    config false       ||
                       ||
         +-------------||--------------------+
         | operational ||                    |
         | state       ||                    |
         |       ======||=================== |
         |       | Applied  Configuration  | |
         |       |(from normal + ephemeral)| |
         |       |                         | |
         |       ==========================  |
         |       _________________________   |
         |       |  derived  state        |  |
         |       |from normal + ephemeral)|  |
         |       |  RIB and protocols     |  |
         |       |________________________|  |
         +-----------------------------------+
    Figure 3

   The ephemeral data store has the following qualities:

   1.  Ephemeral state is not unique to I2RS work.

   2.  The ephemeral datastore is never locked.

   3.  The ephemeral datastore is really a portion of the candidate,
       running, and intended configuration that does not persist over a
       reboot.

       *  Since Ephemeral is just about data not presisting over a
          reboot, then in theory any node or group of nodes in a YANG
          data model could be ephemeral.  The YANG data module must
          indicate what portion of the data model (if any) is ephemeral.



Hares                  Expires September 16, 2016               [Page 7]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


       *  A YANG data module could be all ephemeral (e.g.
          [I-D.ietf-i2rs-rib-data-model]) with no directly associated
          configuration models,

       *  A YANG model could be all ephemeral but associated with a
          configuration model (E.g. (draft-hares-i2rs-bgp-dm-01),

       *  or a single data node or data tree could be made ephemeral.

   4.  The applied configuration is the result of the the intent
       configuration (normal and ephemeral).  Similarly, the derived
       data is a result of the applied configuration.

   5.  Ephemeral portions (node, tree, or data model) need to be
       signalled in the conformance portions of the NETCONF and RESTCONF
       work.  Conformance is signalled in the following ways:

       *  The conformance portion of NETCONF ([RFC6241]) is currently
          signalled in the <hello>.

       *  Yang 1.1 and RESTCONF uses the module library
          ([I-D.ietf-netconf-yang-library])

       *  NETCONF may use the module library in the future.

       *  The ephemeral status in a module will be listed as "all, none
          or partial".  Optionally the module may provide a list of
          nodes.

   6.  The ephemeral data store is treated as one pane of glass that an
       I2RS client(s) may read/write which has the following
       implications:

       *  The ephemeral datastore overlays the configuration datastore
          at each point it touches (candidate, running, and intended
          configuration) By overlays, the I2RS write overwrites a
          previous configuration value, but if a local configuration
          value changes after that over-write the default is to have the
          local-config win.  [aka Last Write wins.]

          +  An example may help to illustrate this default rule.  Say a
             configuration specifies a local route of 128.2/16 with a
             nexthop of 192.5.10.1.  Afterwards an ephemeral route is
             added for 128.2/16 with nexthop of 192.5.10.2.  This
             ephemeral route would replace the first route.  If the
             configuration changes the underlying route (128.2/16 with
             nexthop of 192.5.10.1) and the default rule of local
             configuration is in effect, the local configuration value



Hares                  Expires September 16, 2016               [Page 8]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


             (128.2/16 with nexthop of 192.5.10.1) would take effect.
             This follows the normal netconf concept that Last
             configured wins.  The I2RS agent would notify the I2RS
             Client that the ephemeral route (128.2/16 with nexthop of
             192.5.10.2) had been overwritten by the local
             configuration.

       *  The default of local can be changed by operator-applied policy
          to allow ephemeral to always win or local configuration to
          always win, but the status of the operator applied policy must
          be queryable in the I2RS agent (if that scope) or in the I2RS
          ephemeral data model.  I2RS clients are required to understand
          and handle if the an I2RS agent supports something different
          than the default (aka Last write wins).

4.  Error handling

   Ephemeral nodes level of validation/error handling in the I2RS
   protocol has three following three types:

   o  syntax validation only,

   o  Ephemeral data store allows for reduced error handling that
      removes the requirements for referential checks [I2RS normal error
      handling]

   o  ephemeral data store handling that uses normal NETCONF/RESTCONF
      error handling with syntax and referential [full],

   The default error handling is "no referential checking".

   Normal error handling of I2RS Agent for an I2RS client's information
   examines the following:

   o  message syntax validation,

   o  syntax validation for nodes of data model,

   o  removes referential requirements for leafref checking, MUST
      clauses, and instance indentifier,

   o  grouping of data within a data models or across data models to
      accomplish tasks,

   o  permission to write nodes of data model,

   o  grouping,




Hares                  Expires September 16, 2016               [Page 9]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


   o  priority to write nodes of data model being higher than existing
      priority

   The full error handling status includes all checks included for any
   normal YANG data module uses by NETCONF/RESTCONF.  This includes
   referential checks for leafref checks, MUST clauses, and instance
   identifiers.

   The I2RS Data model sets permissible range of error handling for
   writes on a data model (none, I2RS normal, full), and this may be
   further restricted by an operator applied policy.  If an I2RS client
   requests a lower level of error handling that permissible, the I2RS
   Agent will return an error.

   Multiple I2RS clients writing to the same variable is considered an
   "error condition" in the I2RS architecture
   [I-D.ietf-i2rs-architecture], but the I2RS Agent must handle this
   error condition.  Upon multiple I2RS clients writing, the ephemeral
   data store allows for priority pre-emption of the write operation.
   Priority pre-emption means each I2RS client of the ephemeral I2RS
   agent (netconf server) is associated with a priority.  Priority pre-
   emption occurs when a I2RS client with a higher priority writes a
   node which has been written by an I2RS client (with the lower
   priority).  At this point, the I2RS agent (netconf server) allows the
   write and provides a notification indication to the notification
   publication/subscription service.

   This section describes the ephemeral data stores handling of each of
   these error functions.

4.1.  Syntax validation

   Syntax validation of the message should be done according to the
   NETCONF or RESTCONF protocol features.  New features for ephemeral
   datastore should provide the error handling with the feature.
   Message syntax validation can be for read, write, or rpc functions.

   Syntax validation of the data model included in the ephemeral data
   store should be done by I2RS Agent.

4.2.  Referential validation

   The ephemeral data store normal processing does not do the following
   referencial checks: leafref, MUST, instance identifier.  The removal
   of these validations allows for intelligent I2RS clients to rapidly
   read or write data, and handle error conditions at a higher level.





Hares                  Expires September 16, 2016              [Page 10]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


4.3.  Grouping and Error handling

   Yang 1.0 and Yang 1.1 provide the ability to group data in groupings,
   leafref lists, lists, and containers.  Data model group data in order
   to group data that is logically associated with one another.  Data
   models may logical group data across groupings.  One example of such
   an association is the association of a static route with an
   interface.  The concepts of groupings apply to both ephemeral and
   non-ephemeral nodes within a data model.

4.3.1.  Initial Support of Parital Writes

   The initial releases of I2RS will only require "all-or-nothing" in
   the I2RS Agent.

4.3.2.  Future Scope of multiple message writes

   Error handling on writes of the ephemeral datastore is different for
   nodes that are grouped versus orthogonal.  Group nodes may need to be
   all changed or all removed (all-or-nothing).  In contrast, writing
   orthogonal data nodes in the same data module or between data models
   need to be added or deleted in sync.

   The [I-D.ietf-i2rs-architecture] specifies three types of error
   handling for a partial write operation: "all-or-nothing", "stop-on-
   error", or "continue-on-error".  Partial write operations of "stop-
   on-error" or "continue-on-error" are allowed only for data writes
   which are not a part of a grouping within a data model.  The
   definition of the I2RS error conditions are:

   o  stop-on-error - means that the configuration process stops when a
      write to the configuration detects an error due to write conflict.

   o  continue-on-error - means the configuration process continues when
      a write to the configuration detects an error due to write
      process, and error reports are transmitted back to the client
      writing the error.

   o  all-or-nothing - means that all of the configuration process is
      correctly applied or no configuration process is applied.
      (Inherent in all-or-nothing is the concept of checking all changes
      before applying.)

4.3.2.1.  NETCONF Support of Partial Writes

   NETCONF does not support a mandated sequencing of edit functions or
   write functions.  Without this mandated sequences, NETCONF cannot
   support partial edits.



Hares                  Expires September 16, 2016              [Page 11]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


4.3.2.2.  RESTCONF Support of Partial Writes

   RESTCONF has a complete set of operations per message.  The RESTCONF
   patch can support write functions per messages.

4.4.  priority preemption

   I2RS protocol uses priority to resolve two I2RS clients having
   permissions to write the same pieces of data in an I2RS agent
   (NETCONF server).  If two (or more) I2RS clients attempt to write the
   same data, the the one with the highest priority is enable to write
   the data.  In the case of two clients with teh sample priority
   attempting to write data, the the first one to request write wins.

   Each client has a unique priority.  Client identities and priorities
   are assigned outside of I2RS by exterior mechanisms such as AAA or
   adminstrative interfaces.  A valid I2RS client must have both an
   identity and a priority.

   A client-id and priority must be saved per node.

   A sample container for I2RS client information is shown below.

      container i2rs-clients {
          leaf max-clients {
             config false;
             mandatory true;
             type uint32 {
               range "1 .. max";
             }
          }
          list i2rs-client {
             key name;
             unique priority;
             leaf name { ... }
             leaf priority { ... }
          }
       }
    Figure 4

4.4.1.  Andy Bierman Priority Comment

   (Andy)The priority is not required to be densely numbered.  Whether
   there are 1 pane per client or 1 pane per priority or 1 giant blob
   full of everything, the code will be the same.  The goal of "unique
   priority" is to require that only priority be saved in the meta-data
   for the ephemeral datastore.  Without that, client-id and priority
   must be saved (per data node).



Hares                  Expires September 16, 2016              [Page 12]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


5.  transport protocol

5.1.  Secure Protocols

   NETCONF's XML-based protocol ([RFC6241]) can operate over the
   following secure and encrypted transport layer protocols:

      SSH as defined in [RFC6242],

      TLS with X.509 authentication [RFC7589]

   RESTCONF's XML-based or JSON [RFC7158] data encodings of Yang
   functions are passed over http with (GET, POST, PUT, PATCH, DELETE,
   OPTIONS, and HEAD).

5.2.  Insecure Protocol

   The ephemeral database may support insecure protocols for information
   which is ephemeral state which does not engage in configuration.  The
   insecure protocol must be defined in conjunction with a data model or
   a subdata model.

6.  Yang Library Use by Ephemeral

   The data modules supporting the ephemeral datastore can use the Yang
   module library to describe their datastore.  Figure 5 shows the
   module library data structure as found
   [I-D.ietf-netconf-yang-library].  The I2RS modules will provide
   features for I2RS ephemeral state and protocol of:

   o  protocol version support - "version 1",

   o  ephemeral model scope - ephemeral modules, mixed config module
      (ephemeral and config), mixed derived state (ephemeral and
      config).

   o  ephemeral checking - syntax only, I2RS normal (no referential),
      full (RESTCONF/NETCONF)

   o  multiple message support - "all or nothing",

   o  pane of glass support - "single only".

   o  protocol supported - "NETCONF", "RESTCONF", "NETCONF pub-sub
      push",

   o  encoding support - XML or JSON




Hares                  Expires September 16, 2016              [Page 13]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


   o  transports supported: "TCP", "SSH", "TLS", and others supported.

     +--ro modules
        +--ro module*[name revision]
           +--ro name  yang: yang-identifier
           +--ro revision  union;
           +--ro schema?   inet:uri
           +--ro namespace   inet:uri
           +--ro feature*    yang:yang-identifier
           +--ro deviation* [name revision]
           |  +-- ro name   yang:yang-identifier
           |  +-- ro revision union
           +--ro conformance enumeration
           +--ro submodules
              +--ro submodule*[name revision]
                 +--ro name yang:yang-identifier
                 +--ro revision  union
                 +--ro schema?  inet:uri

                             Figure 5

7.  Simple Thermostat Model

   In this discussion of ephemeral configuration, this draft utilizes a
   simple thermostat model with the YANG configuration found in figure
   6.

   module thermostat {
     ..
     leaf desired-temp {
        type int32;
            units "degrees Celsius";
            description "The desired temperature";
            }

     leaf actual-temp {
        type int32;
            config false;
            units "degrees Celsius";
            description "The measured temperature
            (operational state).";
            }
     }

   Figure 6 - Simple thermostat model yabng

   Figure 6 shows two I2RS clients talking to this model: scheduler and
   hold-temp.  Scheduler has a schedule set of temperatures to put in



Hares                  Expires September 16, 2016              [Page 14]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


   the thermostat.  Hold-temp holds the temperature at the same value.
   The hold-temp I2RS client has a higher priority than the scheduler
   client.

    ...........     ...................    ...........
    :Candidate :---:running config    :--: start-up  :
    :          :   :desired-temp (cfg):  :           :
    ...........     ..................    ...........
                          |  :ephemeral :
                          |  :config    -----|
                          |  :          :    |
                          |  ..|....|....    |
                          |    |    |   =============
                          |    |    |   |I2rs Client|
                          |    |     \  |scheduler  |
                          V    V      \ ============
                 ..................    \
    Intended     . '''''''''''''''      ==============
      Config     . 'desired-temp'       |I2RS Client |
                 . '''''''''^'''' .     | hold temp  |
                 .          |     .     ==============
                 ...........|.......
    config true             |
    ------------------------|-------------
    config false            | (config down,
                            V  status of config up)
                    =============
                    | Actual    |============ I2RS clients
                    | config    |
                    =============

                    ______________
                    | actual temp  |========== I2RS Clients
                    | (op-state)   |
                    ----------------

   Figure 6 - Two I2RS clients

7.1.  Yang changes

   Yang needs to adds key word ephemeral with the following key words:

   o  full-check - defined as NETCONF/RESTCONF relevant error checks,

   o  I2RS checks - defined as no referential checks (see section
      above),

   o  syntax only - defined as only message syntax and model syntax,



Hares                  Expires September 16, 2016              [Page 15]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


   module thermostat {
     ..

     leaf desired-temp {
        type int32;
            units "degrees Celsius";
            ephemeral true;
            ephemeral-validation full-check;
            description "The desired temperature";
            }

     leaf actual-temp {
        type int32;
            config false;
            units "degrees Celsius";
            description "The measured temperature";
            }
     }

   Figure 7 - Simple Thermostat Yang with ephemeral

7.2.  RESTCONF sequence

   Figure 7 shows the thermostat model has ephemeral variable desired-
   temp in the running configuration and the ephemeral data store.  The
   RESTCONF way of addressing is below:

   RESTCONF running data store

   PUT /restconf/data/thermostat:desired-temp
   {"desired-temp":18}

   RESTCONF ephemeral datastore

   PUT /restconf/data/thermostat:desired-temp?datastore=ephemeral
   ?ephemeral-validation="full-check"
   {"desired-temp":19 }

   Figure 8 - RESTCONF setting of ephemeral state

7.3.  NETCONF messages

   The NETCONF way of transmitting this data would be








Hares                  Expires September 16, 2016              [Page 16]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


   <rpc-message-id=101
     xmlns="urn:ietf:params:xml:ns:base:1.0">
     <edit-config>
       <target>
        <ephemeral >
               true
            </ephemeral >
            <ephemeral-validation>
               fullcheck
            </ephemeral-validatio>
       </target>
       <config>
         <top xmlsns="http:://example.com/schema/1.0/thermostat/config>
          <desired-temp> 18 </desired-temp>
         </top>
       </config>
      </edit-config>
   </rpc>

   Note: config=TRUE; datastore = ephemeral
         ephemeral-validation=full-check;

   figure 8 NETCONF setting of desired-temp

8.  NETCONF protocol extensions for the ephemeral datastore

   capability-name: ephemeral-datastore

8.1.  Overview

   This capability defines the NETCONF protocol extensions for the
   ephemeral state.  The ephemeral state has the following features:

   o  the ephemeral datastore is a datastore holds configuration
      information (Config=true) that is intended to not survive a
      reboot.

   o  The ephemeral capbility is signalled as a capability for a node, a
      sub-module, or a module either in the conformance portion of
      NETCONF (<hello>) or via netconf yang module library
      ([I-D.ietf-netconf-yang-library]) used by Yang 1.1 and RESTCONF.

   o  ephemeral data will be noted by an "ephemeral statement at the
      node or module "

   o  The ephemeral datastore is never locked.





Hares                  Expires September 16, 2016              [Page 17]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


   o  The ephemeral data store is one pane of glass that overrides the
      intended config which is normally the running datastore, but can
      be designated as the candidate config.

   o  Ephemeral data nodes can occur as part of protocol or protocol
      independent modules.  However, ephemeral data nodes cannot have
      non-ephemeral data nodes within the subtree.  Ephemeral sub-
      modules cannot have non-ephemeral data nodes wihin the module.
      Ephemeral modules cannot have non-ephemeral sub-modules or nodes
      within the module.

   o  ephemeral writes have two checks: error validation and priority
      premption between two I2RS client writes to the same data.

   o  ephemeral error checking has the following three levels

      *  syntax only - message and data module syntax,

      *  reduced error checking that remove the requirement for leafref
         checking, MUST clauses, and instance identifier validation.

      The default is reduced error checking.

   o  The write operation with a priority pre-emption by a higher
      priority client of the lower priority clients write where the
      overwrite triggers a notification by the I2RS agent to the lower
      priority client.

8.2.  Dependencies

   The following are the dependencies for ephemeral support:

      The Yang data modules must be flag with the ephemeral data store
      at the node, sub-module and model.

      the Yang data models must specify ephemeral validation if the
      models desire validation other reduced error checking.

      The Yang modules must support the notification of write-conflicts.

8.3.  Capability identifier

   The ephemeral-datastore capability is identified by the following
   capability string: (capability uri)







Hares                  Expires September 16, 2016              [Page 18]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


8.4.  New Operations

8.4.1.  link-ephemeral

   The <link-ephemeral> allows the ephemeral datastore to be a pane of
   glass that impacts either the running-config configuration pane of
   glass or the candidate configuration pane of glass.

   <link-ephemeral> target-config

   where target config is:
   writable-running or candidate config.

8.4.2.  Bulk-Write

   Bulk Write allows for large scale writes with error handling that is
   specified as syntax or reduced or full.  Alternatively, the data
   modules can utilize an RPC to do bulk reads/writes.  The bulk write
   will be first check for other I2RS clients having a higher priority
   write value for any of the values.

   Editor: Do we need something beyond rpc for bulk data writes?

8.5.  Modification to existing operations

   The capability for :ephemeral-datastore modifies the target for
   existing operations.

8.5.1.  <get-config>

   The :ephemeral-datastore capability modifies the <edit-config> to
   accept the <ephemeral> as a target for source, and allows the filters
   focused on a particular module, submodule, or node.

   The positive and negative responses remain the same.
















Hares                  Expires September 16, 2016              [Page 19]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


   Example - retrieve users subtree from
             ephemeral database

    <rpc message-id="101"
     xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <get-config>
         <source>
           <emphemeral-datastore/>
         </source>
         <filter type="subtree">
           <top xmlns="http://example.com/schema/1.0/thermostat/config">
           <desired-temp>
            </top>
         </filter>
      </get-config>
    </rpc>

8.5.2.  <edit-config>

   The :ephemeral-datastore capability modifies the <edit-config> to
   accept the <ephemeral> as a target for source with filters.  The
   operations of merge, replace, create, delete, and remove are
   available, but each of these operations is modified by the priority
   write as follows:

      <merge> parameter is replaced by <merge-priority> The current data
      is modified by the new data in a merge fashion only if existing
      data either does not exist, or is owned by a lower priority
      client.  If any data is replaced, this event is passed to the
      notification function within the pub/sub and traceability.

      <replace> is replaced by <replace-priority> for ephemeral
      datastore which replaces data if the existing data is owned by a
      lower priority client.  If data any data is replaced, this event
      is passed to the notification function within pub/sub and
      traceability for notification to the previous client.  The success
      or failure of the event is passed to traceabilty.

      <create> - the creation of the data node works as in [RFC6241]
      except that the success or failure is passed to pub/sub and
      traceability functions.

      <deletion> - the deletion of the data node works as in [RFC6241]
      except event that the success or the error event is passed to the
      notiication function withi pub/sub and traceability functions.

      <remove> - the remove of the data node works as in [RFC6241]
      except that all results are forwarded to traceabilty.



Hares                  Expires September 16, 2016              [Page 20]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


   The existing parameters are modified as follows:

      <target> - add a target of :emphemeral-datastore

      <default-operation> -allows only <merge-priority> or <replace-
      priority>

      <error-option> - the I2RS agent agent supports only the a"all-or-
      nothing" equivalent to a "rollback-on-error" function.

      positive response - the <ok> is sent for a positive response
      within an <rpc-reply>.

      negative response - the <rpc-error> is sent for a negative
      response within an <rpc-reply>.  Note a negative respones may
      evoke a publication of an event.

8.5.3.  <copy-config>

   Copy config allows for the complete replacement of all the ephemeral
   nodes within a target.  The alternation is that source is the
   :ephemeral datastore with the filtering to match the datastore.  The
   following existing parameters are modified as follows:

      <target> - add a target of :emphemeral-datastore

      <error-option> - the I2RS agent agent supports only the a"all-or-
      nothing" equivalent to a "rollback-on-error" function.

      positive response - the <ok> is sent for a positive response
      within an <rpc-reply>.

      negative response - the <rpc-error> is sent for a negative
      response within an <rpc-reply>.

8.5.4.  <delete-config>

   The delete will delete all ephemeral nodes out of a datastore.  The
   target parameter must be changed to allow :ephemeral-datastore.  and
   filters.

8.5.5.  <lock> and <unlock>

   Lock and unlock are not supported with a target of :ephemeral-
   datastore.






Hares                  Expires September 16, 2016              [Page 21]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


8.5.6.  <get>

   The <get> is altered to allow a target of :ephemeral-datastore and
   with the filters.

8.5.7.  <close-session> and <kill-session>

   The close session is modified to take a target of :ephemeral-
   datastore Since no locks are set, none should be released.

   The kill session is modified to take a target of "ephemeral-
   datastore.  Since no locks are set, none should be released.

8.6.  Interactions with Capabilities

   [RFC6241] defines NETCONF capabilities for writeable-running
   datastore, candidate config data store, confirmed commit, rollback-
   on-error, validate, distinct start-up, URL capability, and XPATH
   capability.

8.6.1.  writable-running and candidate datastore

   The writeable-running and the candidate datastore can be used in
   conjunction with the ephemeral data store.  Ephemeral database
   overlays an intended configuration, and may overlay candidate and
   running configuration data store.  The <link-ephemeral> operation
   links to these two databases.

8.6.2.  confirmed commmit

   Confirmed commit capability is not supported for the ephemeral
   datastore.

8.6.3.  rollback-on-error

   The rollback-on-error when included with ephemeral state allows the
   error handling to be "all-or-nothing" (roll-back-on-error).

8.6.4.  validate

   The <validate> key word is expanded to support the following:

      source: ephemeral-datastore

      validate: (syntax, no-referential, full) with the following
      definitions:





Hares                  Expires September 16, 2016              [Page 22]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


      *  syntax - validates only the message syntax and the data base
         syntax.

      *  no-referentail - skips referential test (leafref, MUST clauses,
         and instance identifiers).

      *  full - all normal netconf/restconf module error chcking

8.6.5.  Distinct Startup Capability

   This NETCONF capability appears to operate to load write-able running
   config, running-config, or candidate datastore.  The ephemeral state
   does not change the environment based on this command.

8.6.6.  URL capability and XPATH capability

   The URL capabilities specify a <url> in the <source> and <target>.
   The initial suggestion to allow both of these features to work with
   ephemeral operation.

9.  RESTCONF protocol extensions for the ephemeral datastore

   capability-name: ephemeral-datastore

9.1.  Overview

   This capability defines the RESTCONF protocol extensions for the
   ephemeral state.  The ephemeral state has the features described in
   the previous section on NETCONF.

9.2.  Dependencies

   The ephemeral capabilities have the following dependencies:

      Yang data nodes, sub-modules, or modules must be flaged with the
      config datastore flag;

      The Yang modules must support the notification of write-conflicts.

      The I2RS Yang modules must support the following:

         the yang-patch features as specified in
         [I-D.ietf-netconf-yang-patch].

         The yang module library feature
         [I-D.ietf-netconf-yang-library],





Hares                  Expires September 16, 2016              [Page 23]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


9.3.  Capability identifier

   The ephemeral-datastore capability is identified by the following
   capability string: (capability uri)

9.4.  New Operations

   none

9.5.  modification to data resources

   RESTCONF must be able to support the ephemeral datstore with its
   rules as part of the "{+restconf}/data" subtree.  The "edit
   collision" features in RESTCONF must be able to provide notification
   to I2RS read functions or to rpc functions.  The "timestamp" with a
   last modified features must support the traceability function.

   The "Entity Tag" could support saving a client-priority tuple as a
   opaque string, but it is important that that additions be made to
   restore client-priority so it can be compared with stromgs to be
   added.

9.6.  Modification to existing operations

   The current operations in RESTCONF are: OPTIONS, HEAD, GET, POST,
   PUT, PATCH, and DELETE.  This section describes the modification to
   these exiting operations.

9.6.1.  OPTIONS changes

   The options methods should be augmented by the
   [I-D.ietf-netconf-yang-library] information that will provide an
   indication of what ephemeral state exists in a data modules, or a
   data modules sub-modules or nodes.

9.6.2.  HEAD changes

   The HEAD in retrieving the headers of a resources.  It would be
   useful to changes these headers to indicate the datastore a node or
   submodule or module is in (ephemeral or normal), and allow filtering
   on ephemeral nodes or trees, submodules or module.

9.6.3.  GET changes

   GET must be able to read from the URL and a particular datastore.
   Similarly, it is important the Get be able to determine if it is a
   ephemeral data store.




Hares                  Expires September 16, 2016              [Page 24]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


9.6.4.  POST changes

   POST must simply be able to create resources in ephemeral datastores
   ("=datastore=ephemeral") and invoke operations defined in ephemeral
   data models using the rules of the ephemeral database.

9.6.5.  PUT changes

   PUT must be able to reference an ephemeral module, sub-module, and
   nodes ("?datastore=ephemeral").

9.6.6.  PATCH changes

   Plain PATCH must be able to update or create child resources in an
   ephemeral datastore ("?datstore=ephemeral") The PATCH for the
   ephemeral state must be change to provide a merge or update of the
   original data only if the client's using the patch has a higher
   priority than an existing datastore's client, or if PATCH requests to
   create a new node, sub-module or module in the datastore.

9.6.7.  DELETE changes

   The phrase "?datastore=ephemeral" following an element will specify
   the ephemeral data store when deleting entry.

9.6.8.  Query Parameters

   The query parameters (content, depth, fields, insert, point, start-
   time, stop-time, and with-defaults (report-all, trim, explicit,
   report-all-tagged) must support ephemeral datastores
   ("?datastore=ephemeral") described above.

9.7.  Interactions with Notifications

   The ephemeral database must support subscribing to receiving
   notifications as Event stream.  The event error stream processing
   should support the publication/subscription mechanisms for ephemeral
   state defined in [I-D.ietf-netconf-yang-push].

9.8.  Interactions with Error Reporting

   The ephemeral database] support in RESTCONF must also support passing
   error information regarding ephemeral data access over to RESTCONF
   equivalent of the and traceability client.







Hares                  Expires September 16, 2016              [Page 25]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


10.  IANA Considerations

   This is a protocol strawman - nothing is going to IANA.

11.  Security Considerations

   The security requirements for the I2RS protocol are covered in
   [I-D.ietf-i2rs-protocol-security-requirements].  The security
   environment the I2RS protocol is covered in
   [I-D.ietf-i2rs-security-environment-reqs].  Any person implementing
   or deploying the I2RS protocol should consider both security
   requirements.

12.  Acknowledgements

   This document is an attempt to distill lengthy conversations on the
   I2RS proto design team from August

   Here's the list of the I2RS protocol design team members

   o  Alia Atlas

   o  Ignas Bagdonas

   o  Andy Bierman

   o  Alex Clemm

   o  Eric Voit

   o  Kent Watsen

   o  Jeff Haas

   o  Keyur Patel

   o  Hariharan Ananthakrishnan

   o  Dean Bogdanavich

   o  Anu Nair

   o  Juergen Schoenwaelder

   o  Kent Watsen






Hares                  Expires September 16, 2016              [Page 26]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


13.  Major Contributors

   o  Andy Bierman (Yuman Networks) - andy@yumaworks.com

   o  Kent Watson (Juniper) (kwatsent@juniper.net)

14.  References

14.1.  Normative References:

   [I-D.hares-i2rs-dataflow-req]
              Hares, S., "I2RS Data Flow Requirements", draft-hares-
              i2rs-dataflow-req-01 (work in progress), March 2016.

   [I-D.ietf-i2rs-architecture]
              Atlas, A., Halpern, J., Hares, S., Ward, D., and T.
              Nadeau, "An Architecture for the Interface to the Routing
              System", draft-ietf-i2rs-architecture-13 (work in
              progress), February 2016.

   [I-D.ietf-i2rs-ephemeral-state]
              Haas, J. and S. Hares, "I2RS Ephemeral State
              Requirements", draft-ietf-i2rs-ephemeral-state-04 (work in
              progress), March 2016.

   [I-D.ietf-i2rs-protocol-security-requirements]
              Hares, S., Migault, D., and J. Halpern, "I2RS Security
              Related Requirements", draft-ietf-i2rs-protocol-security-
              requirements-03 (work in progress), March 2016.

   [I-D.ietf-i2rs-pub-sub-requirements]
              Voit, E., Clemm, A., and A. Prieto, "Requirements for
              Subscription to YANG Datastores", draft-ietf-i2rs-pub-sub-
              requirements-05 (work in progress), February 2016.

   [I-D.ietf-i2rs-rib-data-model]
              Wang, L., Ananthakrishnan, H., Chen, M.,
              amit.dass@ericsson.com, a., Kini, S., and N. Bahadur, "A
              YANG Data Model for Routing Information Base (RIB)",
              draft-ietf-i2rs-rib-data-model-04 (work in progress),
              November 2015.

   [I-D.ietf-i2rs-rib-info-model]
              Bahadur, N., Kini, S., and J. Medved, "Routing Information
              Base Info Model", draft-ietf-i2rs-rib-info-model-08 (work
              in progress), October 2015.





Hares                  Expires September 16, 2016              [Page 27]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


   [I-D.ietf-i2rs-security-environment-reqs]
              Migault, D., Halpern, J., and S. Hares, "I2RS Environment
              Security Requirements", draft-ietf-i2rs-security-
              environment-reqs-00 (work in progress), October 2015.

   [I-D.ietf-i2rs-traceability]
              Clarke, J., Salgueiro, G., and C. Pignataro, "Interface to
              the Routing System (I2RS) Traceability: Framework and
              Information Model", draft-ietf-i2rs-traceability-07 (work
              in progress), February 2016.

   [I-D.ietf-netconf-restconf]
              Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", draft-ietf-netconf-restconf-09 (work in
              progress), December 2015.

   [I-D.ietf-netconf-yang-library]
              Bierman, A., Bjorklund, M., and K. Watsen, "YANG Module
              Library", draft-ietf-netconf-yang-library-04 (work in
              progress), February 2016.

   [I-D.ietf-netconf-yang-patch]
              Bierman, A., Bjorklund, M., and K. Watsen, "YANG Patch
              Media Type", draft-ietf-netconf-yang-patch-07 (work in
              progress), December 2015.

   [I-D.ietf-netconf-yang-push]
              Clemm, A., Prieto, A., Voit, E., Tripathy, A., and E.
              Einar, "Subscribing to YANG datastore push updates",
              draft-ietf-netconf-yang-push-01 (work in progress),
              February 2016.

   [I-D.ietf-netmod-opstate-reqs]
              Watsen, K. and T. Nadeau, "Terminology and Requirements
              for Enhanced Handling of Operational State", draft-ietf-
              netmod-opstate-reqs-04 (work in progress), January 2016.

   [I-D.ietf-netmod-yang-metadata]
              Lhotka, L., "Defining and Using Metadata with YANG",
              draft-ietf-netmod-yang-metadata-06 (work in progress),
              March 2016.

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






Hares                  Expires September 16, 2016              [Page 28]


Internet-Draft      I2RS Ephemeral State Requirements         March 2016


   [RFC7158]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
              Interchange Format", RFC 7158, DOI 10.17487/RFC7158, March
              2014, <http://www.rfc-editor.org/info/rfc7158>.

   [RFC7589]  Badra, M., Luchuk, A., and J. Schoenwaelder, "Using the
              NETCONF Protocol over Transport Layer Security (TLS) with
              Mutual X.509 Authentication", RFC 7589,
              DOI 10.17487/RFC7589, June 2015,
              <http://www.rfc-editor.org/info/rfc7589>.

14.2.  Informative 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>.

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

   [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>.

   [RFC6536]  Bierman, A. and M. Bjorklund, "Network Configuration
              Protocol (NETCONF) Access Control Model", RFC 6536,
              DOI 10.17487/RFC6536, March 2012,
              <http://www.rfc-editor.org/info/rfc6536>.

Author's Address

   Susan Hares
   Huawei
   Saline
   US

   Email: shares@ndzh.com











Hares                  Expires September 16, 2016              [Page 29]


Html markup produced by rfcmarkup 1.129c, available from https://tools.ietf.org/tools/rfcmarkup/