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I2RS working group                                              S. Hares
Internet-Draft                                                    Huawei
Intended status: Informational                                   A. Dass
Expires: January 9, 2017                                        Ericsson
                                                            July 8, 2016


                         I2RS protocol strawman
               draft-hares-i2rs-protocol-strawman-03.txt

Abstract

   This strawman proposal discusses requirement, design, and
   implementation issues for an I2RS protocol which supports I2RS
   requirements for ephemeral data store, management data flows, and
   protocol security.  It proposes additions to the NETCONF, RESTCONF,
   and YANG for these requirements.

   This document is a living document providing insights gained in
   design, implementation and debugging of the I2RS protocol.

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
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   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
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   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 9, 2017.

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



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   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Definitions Related to Ephemeral Configuration  . . . . . . .   4
     2.1.  Requirements language . . . . . . . . . . . . . . . . . .   4
     2.2.  I2RS Definitions  . . . . . . . . . . . . . . . . . . . .   5
     2.3.  Operational and Ephemeral State definitions . . . . . . .   6
   3.  DataStore Model Melee . . . . . . . . . . . . . . . . . . . .   7
     3.1.  Opstate model . . . . . . . . . . . . . . . . . . . . . .   7
     3.2.  Persistent/Non-Persistent Config  . . . . . . . . . . . .  10
     3.3.  Revised Data Store (Ephemeral is OPSTATE  . . . . . . . .  11
     3.4.  Another Model for Ephemeral . . . . . . . . . . . . . . .  13
   4.  Summary of Protocol Changes . . . . . . . . . . . . . . . . .  14
     4.1.  Ephemeral Data  . . . . . . . . . . . . . . . . . . . . .  14
       4.1.1.  Overview of Ephemeral Data Store  . . . . . . . . . .  14
       4.1.2.  I2RS Agent Caching of Ephemeral Data  . . . . . . . .  15
     4.2.  Protocol Security . . . . . . . . . . . . . . . . . . . .  15
       4.2.1.  Summary of Protocol Security Changes  . . . . . . . .  15
     4.3.  Data Flow . . . . . . . . . . . . . . . . . . . . . . . .  17
       4.3.1.  Data Flow for Ephemeral Configuration . . . . . . . .  17
       4.3.2.  Write Error handling  . . . . . . . . . . . . . . . .  18
       4.3.3.  Data Flows From the I2RS Agent to I2RS Client . . . .  22
       4.3.4.  OAM Constraints . . . . . . . . . . . . . . . . . . .  23
       4.3.5.  IPFIX for traffic monitoring  . . . . . . . . . . . .  23
     4.4.  Yang Changes  . . . . . . . . . . . . . . . . . . . . . .  23
     4.5.  Transport Protocol Changes  . . . . . . . . . . . . . . .  24
       4.5.1.  Secure Protocols  . . . . . . . . . . . . . . . . . .  24
       4.5.2.  Insecure Protocol . . . . . . . . . . . . . . . . . .  24
     4.6.  NETCONF protocol extensions for the ephemeral datastore .  24
       4.6.1.  Overview  . . . . . . . . . . . . . . . . . . . . . .  25
       4.6.2.  Dependencies  . . . . . . . . . . . . . . . . . . . .  26
       4.6.3.  Capability identifier . . . . . . . . . . . . . . . .  26
       4.6.4.  New Operations  . . . . . . . . . . . . . . . . . . .  26
       4.6.5.  Modification to existing operations . . . . . . . . .  26
       4.6.6.  Interactions with Capabilities  . . . . . . . . . . .  29
     4.7.  RESTCONF protocol extensions for the ephemeral datastore   31
       4.7.1.  Overview  . . . . . . . . . . . . . . . . . . . . . .  31
       4.7.2.  Dependencies  . . . . . . . . . . . . . . . . . . . .  31
       4.7.3.  Capability identifier . . . . . . . . . . . . . . . .  32
       4.7.4.  New Operations  . . . . . . . . . . . . . . . . . . .  32
       4.7.5.  modification to data resources  . . . . . . . . . . .  32
       4.7.6.  Modification to existing operations . . . . . . . . .  32
       4.7.7.  Interactions with Notifications . . . . . . . . . . .  33



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       4.7.8.  Interactions with Error Reporting . . . . . . . . . .  33
   5.  Simple Thermostat Model . . . . . . . . . . . . . . . . . . .  34
     5.1.  YANG data model . . . . . . . . . . . . . . . . . . . . .  35
     5.2.  NETCONF Changes . . . . . . . . . . . . . . . . . . . . .  40
     5.3.  RESTCONF Initial Write  . . . . . . . . . . . . . . . . .  40
   6.  Simple Route Add  . . . . . . . . . . . . . . . . . . . . . .  40
     6.1.  Portions of I2RS YANG data model  . . . . . . . . . . . .  43
     6.2.  NETCONF Changes . . . . . . . . . . . . . . . . . . . . .  45
     6.3.  RESTCONF Changes  . . . . . . . . . . . . . . . . . . . .  45
   7.  Previously Considered Ideas . . . . . . . . . . . . . . . . .  45
     7.1.  A Separate Ephemeral Data store . . . . . . . . . . . . .  45
     7.2.  Panes of Glass/Overlay  . . . . . . . . . . . . . . . . .  46
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  46
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  46
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  46
   11. Major Contributors  . . . . . . . . . . . . . . . . . . . . .  47
   12. List of I2RS Requirements . . . . . . . . . . . . . . . . . .  47
   13. References  . . . . . . . . . . . . . . . . . . . . . . . . .  47
     13.1.  Normative References:  . . . . . . . . . . . . . . . . .  48
     13.2.  Informative References . . . . . . . . . . . . . . . . .  49
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  51

1.  Introduction

   This is a strawman proposal for the first version of the I2RS
   protocol.  This draft is input to a NETCONF Working Group which
   standardizes extensions to the NETCONF and RESTCONF protocol, and to
   the NETMOD Working Group which standardizes extensions to YANG.  This
   draft is also input to the early implementers of the I2RS protocol.
   As such, feedback from early implementations would help.

   The I2RS protocol is a higher level protocol comprised of a set of
   existing protocols which have been extended to work together to
   support a new interface to the routing system.  The I2RS protocol is
   a "reuse" management protocol which creates new management protocols
   by reusing existing protocols and extending these protocols for new
   uses.  The first version of the I2RS protocols is comprised of
   extensions of the NETCONF [RFC6241] and RESTCONF
   [I-D.ietf-netconf-restconf].

   This strawman proposal supports I2RS requirements for ephemeral data
   store, management data flows, and protocol security.  It proposes
   extensions to the following:

   o  YANG 1.1 [I-D.ietf-netmod-rfc6020bis],

   o  NETCONF [RFC6241],




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   o  RESTCONF [I-D.ietf-netconf-restconf]

   o  Network Access Control Model [RFC6536]

   This protocol strawman utilizes the following existing proposed
   features for NETCONF and RESTCONF

   o  Call Home [I-D.ietf-netconf-call-home],

   o  Server Configuratino Module [I-D.ietf-netconf-server-model],

   o  Module library [I-D.ietf-netconf-yang-library],

   o  Publication/Subscription via Push [I-D.ietf-netconf-yang-push],

   o  Patch [I-D.ietf-netconf-yang-patch],

   o  syslog yang module (both [RFC5424] and
      [I-D.ietf-netmod-syslog-model]

   Section 2 provides definitions for terms in this document.  Section 3
   summarizes the changes to configuration data store, NETCONF,
   RESTCONF, and YANG.  Section 4 details the changes to Yang.
   Section 5 summarizes the changes to transport support for RESTCONF
   and NETCONF.  Section 6 details the changes to NETCONF.  Section 7
   details the changes to RESTCONF.  Section 8 provides a simple example
   of I2RS protocol support for the ephemeral data store using a simple
   temperature model.  Section 9 provides a simple example of the I2RS
   protocol with an ephemeral route updating an existing route.
   Section 10 provides information on the security considerations for
   the I2RS protocol.

2.  Definitions Related to Ephemeral Configuration

   This section reviews definitions from I2RS architecture
   [I-D.ietf-i2rs-architecture] and NETCONF operational state
   [I-D.ietf-netmod-opstate-reqs] before using these to construct a
   definition of the ephemeral data store.

2.1.  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 [RFC2119].







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2.2.  I2RS Definitions

   The I2RS architecture [I-D.ietf-i2rs-architecture] defines the
   following terms:

   ephemeral data:   is data which does not persist across a reboot
      (software or hardware) or a power on/off condition.  Ephemeral
      data can be configured data or data recorded from operations of
      the router.  Ephemeral configuration data also has the property
      that a system cannot roll back to a previous ephemeral
      configuration state.

   local configuration:   is the data on a routing system which does
      persist across a reboot (software or hardware) and a power on/off
      condition.  Local configuration has the ability to roll back to a
      pervious configuration state.

   operator-applied policy:    is a policy that an operator sets that
      determines how ephemeral configuration interacts with local
      configuration.  One could consider these policy knobs that the
      operator sets to determine how the I2RS agent will act.  Two
      policy knobs are necessary:

      *  policy knob 1: Ephemeral configuration overwrites local
         configuration,

      *  policy knob 2: Updated configuration overwrites ephemeral
         configuration

   Three possible setting for the above knobs are:

   Policy knob 1=false and policy knob 2=true:   I2RS software is
      installed, but the operator does not want it to overwrite write
      any configuration variables.  This might be valid if I2RS is only
      suppose to monitor data on this node.

   Policy knob 1=true and policy Knob 2=false:    This is the normal
      case for the I2RS Agent where the ephemeral configuration data
      overwrites the local configuration data, and the ephemeral data
      stays even when the local configuration value changes.  When the
      ephemeral data is removed by the I2RS agent, the most recent local
      configuration value is set.

   Policy knob 1=true and Policy Knob 2=true:    This case can occur if
      the ephemeral write is only suppose to take place until the next
      configuration cycle from a centralized system.  Suppose the local
      configuration is get by the centralized system at 11:00pm each
      night.  The I2RS Client writes temporary changes to the routing



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      system via the I2RS agent ephemeral write.  At 11:00pm, the local
      configuration update overwrite the ephemeral.  The I2RS Agent
      notifies the I2RS Client which is tracking which of the ephemeral
      changes are being overwritten.

2.3.  Operational and Ephemeral State definitions

   The [I-D.ietf-netmod-opstate-reqs] defines the following to augment
   [RFC6244] to define how configuration state and operational state are
   different.

   Applied Configuration:    This data represents the configuration
      state that the server is actually in.

    Derived State:    This data represents information which is
      generated as part of the server's own interactions.

   Intended Configuration:    This data is the configuration state that
      the network operator intends the server to be in, and that has
      been accepted by the server as valid configuration.

   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.

   Ephemeral State:    contains both ephemeral configuration state and
      operational state.  In a data model which is only ephemeral, the
      operational data created based on ephemeral configuration state.
      In a non-ephemeral data model, the ephemeral augmentatation to
      operational state may create ephemeral operational state.

   Ephemeral Configuration state:   Ephemeral configuration state is
      state which is an ephemeral only data modules or ephemeral
      configuration that augments a non-ephemeral data model."

   In each of these definitions, the "server" is the routing system.

   The [I-D.ietf-netmod-opstate-reqs] defines two actions that update
   the intended and the applied configuration:

   Asynchronous Configuration Operation:    the server MUST update its
      intended configuration before replying to the client indicating
      whether the request will be processed.  The server's applied
      configuration state is updated after the configuration change has
      been fully effected to all impacted components in the server.





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   Synchronous Configuration Operation:    the server MUST fully attempt
      to apply the configuration change to all impacted components in
      the server, updating both its configuration (intended
      configuration and the applied configuration), before replying to
      the client.

3.  DataStore Model Melee

   The NETMOD Working Group has been working to create new definitions
   of datastores based on feedback from operators on desiring a split
   between operational state and configuration state.

   In a system without ephemeral data, the structure of the routing
   systems local intended configuration, applied configuration, and
   derived state can be modeled in the following ways:

   1.  Opstate model from I-D.draft-kwatsen-netmod-opstate (figure 1
       below),

   2.  Persistent/Non-Persistent Config from I-D.draft-wilton-netmod-
       refined-datastores (figure 2 below) ,

   3.  Revised Data Store (Ephemeral is OPSTATE ) from I-D.draft-
       schoenw-netmod-revised-datastores (figure 3)

   4.  I2RS model (figure 4 below in section 2.4.1).

   Section 2.4.1-2.4.4 provide diagrams and pro/cons of each model.
   Operational experience will improve our understanding of these
   datastore models.

3.1.  Opstate model

   Model from: I-D.draft-kwatsen-netmod-opstate

















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     Local Configuration

                      |  Synchronous
                      |  or Asychronous updsate
                      |
              ===========================
              |  local                  |
              | intended configuration  |
              ===========================
                          ||    read/write
         -----------------||-------------------
                          ||   read only
            +-------------||------+
            | operational ||      |
            | state       ||      |
            |    =========||==    |
            |    | Applied   |    |
     config |    | config    |    |
       true |    =============    |
     ******************************
     config |   _____________     |
      false |   |  derived  |     |
            |   |  state    |     |
            |   |___________|     |
            +---------------------+

                    Figure 1

   I2RS Proposed Ephemeral state addition to Model






















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                      |  Synchronous
                      |  or Asychronous updsate
                      |
             ================================
             | Local         | Ephemeral    |=====I2RS Agent
             | configuration | Confguration |
             |''''''''''''''''''''''''''''''|
             | Intended  configuration      |
             =============||=================
                          ||    read/write
                         -||-------------------
                          ||   read only
            +-------------||-------------+
            | operational ||             |
            | state       ||             |
            |    =========||==========   |
            |    | Local  * ephemeral|   |
            |    | config * config   |   |
     config |    | Applied config    |   |
       true |    =====================   |
     ****************************************
     config |   ______________________   |
      false |   | local  * ephemeral |   |
            |   | state  *  state    |   |
            |   |  derived state     |   |
            |   |_____________________   |
            +----------------------------+
    Figure 2

   Pro:

   1.  Ephemeral configuration utilize the constraint checks in yang 1.1
       [I-D.ietf-netmod-rfc6020bis] in section 8.3 for message
       syntactial checks (8.3.1), and can use insertion and datastore
       based constraint checking in NETCONF/RESTCONF in their normal
       manner (section 8.3.2 and 8.3.3).

   2.  Operational state can occur in ephemeral only data models

   3.  Ephemeral augmentations seem a logical extension.

   4.  Event/notification for I2RS can work with config and ephemeral.

   5.  Can query ephemeral + local configurations as overlay or
       separately.

   Con:




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   1.  Ephemeral configuration cannot elect to use only the Yang 1.1
       syntactical checks (section 8.3.1 of
       [I-D.ietf-netmod-rfc6020bis]).

3.2.  Persistent/Non-Persistent Config

   Persistent/Non-Persistent Config from I-D.draft-wilton-netmod-
   refined-datastores


         +-------------+                  +-----------+
         | <candidate> |                  | <startup> |
         |  (ct, rw)   |<---+        +--->| (ct, rw)  |
         +-------------+    |        |    +-----------+
                |           |        |          |
                |      .....|........|........  |
                |      . +-----------------+ .  |
                +------->|<persistent cfg> |<---+
                       . | (ct, rw)        | .
         Intended      . +-----------------+ .
          Config   ==> .         v           .
         Datastore     . +-----------------+ .
         (abstract)    . |<ephemeral cfg>  |<--- Can override persistent
                       . | (ct, rw)        | .   cfg. Optional
                       . +-----------------+ .
                       ..........|............
                                 |
                       +---------v-----------+
                       | ................... |
                       | . <applied cfg>   .<--- Actual cfg in effect
        Operational    | . (ct, ro)        . |
           State   ==> | ................... |
         Datastore     |         +           |
                       |    system cfg      <--- System created config
                       |         +           |
                       |    system state    <--- All config false nodes
                       +---------------------+

   Pro:

   1.  Ephemeral configuration utilize the constraint checks in yang 1.1
       [I-D.ietf-netmod-rfc6020bis] in section 8.3 for message
       syntactial checks (8.3.1), and can use insertion and datastore
       based constraint checking in NETCONF/RESTCONF in their normal
       manner (section 8.3.2 and 8.3.3).

   2.  Operational state can occur in ephemeral only data models




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   3.  Ephemeral augmentations align with the I2RS ephemeral
       requirements [I-D.ietf-i2rs-ephemeral-state]

   4.  Event/notification for I2RS can work with config and ephemeral.

   5.  Can query ephemeral + local configurations as overlay or
       separately.

   Con:

   1.  Ephemeral configuration cannot elect to use only the Yang 1.1
       syntactical checks (section 8.3.1 of
       [I-D.ietf-netmod-rfc6020bis]).

3.3.  Revised Data Store (Ephemeral is OPSTATE

   Revised Data Store (Ephemeral is OPSTATE ) from I-D.draft-schoenw-
   netmod-revised-datastores

































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  +-------------+                  +-----------+
  | <candidate> |                  | <startup> |
  |  (ct, rw)   |<---+        +--->| (ct, rw)  |
  +-------------+    |        |    +-----------+
         |           |        |           |
         |         +------------+         |
         +--------<| <running>  |>--------+
                   | (ct, rw)   |
                   +------------+
                         |
                        (A)       // e.g., removal of 'inactive' nodes
                         v
                   +------------+
                   | <intended> | // subject to validation
                   | (ct, ro)   |
                   +------------+
                         |
                        (B)       // e.g., missing resources or delays
                         v
                   +------------+
                   | <applied>  |
                   | (ct, ro)   |
                   +------------+
                         |
                        (C)       // e.g., autodiscovery, control-plane
                         |        // protocols, control-plane datastores
                         v
         +--------------------------------+
         | <operational-state>            |
         | (ct + cf, ro)                  |
         +--------------------------------+

   Pro:

   1.  Ephemeral configuration can tailor its constraint checking to the
       data model.

   2.  Ephemeral data is like data sent to/from any routing process.

   Con:

   1.  Ephemeral configuration state must create its own constraint
       checking

   2.  Ephemeral state has no easy way to query the overlay of ephemeral
       state and local configuration since there is no augmentation of
       local configuration.




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   3.  Event/notification for I2RS can work with config and ephemeral.

   4.  Ephemeral configuration

3.4.  Another Model for Ephemeral

   This model came out of dicussions with the authors of all the drafts:

                  +---------------+
                                  | Ephemeral     |
                                  | Configuration |
                  +---------------+
                                        ^  |
                        |  |
  +-------------+       |  |       +-----------+
  | <candidate> |       |  |       | <startup> |
  |  (ct, rw)   |<---+  |  |  +--->| (ct, rw)  |
  +-------------+    |  |  |  |    +-----------+
         |           |  |  V  |           |
         |         +------------+         |
         +-------->| <running>  |<--------+
                   | (ct, rw)   |
                   +------------+
                         |
                        (A)       // e.g., removal of 'inactive' nodes
                         v
                   +------------+
                   | <intended> | // subject to validation
                   | (ct, ro)   |
                   +------------+
                         |
                        (B)       // e.g., missing resources or delays
                         v
                   +------------+
                   | <applied>  |
                   | (ct, ro)   |
                   +------------+
                         |
                        (C)       // e.g., autodiscovery, control-plane
                         |        // protocols, control-plane datastores
                         v
 +---------+      +----------------------------+  +--------------+
 |injected |-->| <operational-state>  |  |  forwarding  |
 |ephemeral|      | process (ct + cf,      |------|              |
 |         |      |   ro + injected  )     |      |              |
 +---------+      +------------------------+      +--------------+





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4.  Summary of Protocol Changes

   This section provides a summary of requirements for changes to
   support the I2RS protocol features of ephemeral data, a secure
   protocol, management data flows, and I2RS error handling.  Management
   data flows may be large data flows for notifications, events, and
   protocol events.  Management flows could also be tracing the routing
   system's operation or OAM operations.

4.1.  Ephemeral Data

   This section provides an overview of the ephemeral data store, I2RS
   agent caching support, and ephemeral requirements (from
   [I-D.ietf-i2rs-ephemeral-state]).

4.1.1.  Overview of Ephemeral Data Store

   This section augments the [I-D.ietf-netmod-opstate-reqs] with
   definitions for ephemeral state as the longest held NETMOD datastore
   model.  Any of the ephemeral data models described above can be made
   to align to ephemeral state, but the revised data store (ephemeral is
   operation state ) may take more effort.

   NETCONF provides the concept of a data store, but RESTCONF only
   defines the concept of a "context".  The logical description of
   ephemeral additions to the NETCONF data store below still fits the
   general concepts of the RESTCONF context.

   This approach to the ephemeral datastore is two panes-of-glass model
   one pane of glass is the "local configuration" within the Intended
   configuration and the other pane of glass is the "ephemeral data".
   The two panes of glass are pressed together to create the intended
   configuration which then applied to the routing node and generates
   derived state as shown in figure 2.

   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 (normal and ephemeral).
   Therefore derived state may be defined in local configuration or
   ephemeral portions of a data model (or data models).

   The ephemeral data store has the following general qualities:

   1.  Ephemeral state is not unique to I2RS work.

   2.  The ephemeral datastore is never locked.





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   3.  The ephemeral portion of the intended configuration, applied
       state, and derived state does not persist over a reboot,

   4.  an ephemeral node cannot roll-back to its previous value,

   5.  Since ephemeral data store is just data that does not presist
       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.

       *  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

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

   6.  The management protocol (NETCONF/RESTCONF) needs to signal which
       poritons of a data model(node, tree, or data model) are ephemeral
       in the module library [I-D.ietf-netconf-yang-library].

4.1.2.  I2RS Agent Caching of Ephemeral Data

   I2RS protocol version does not support caching of ephemeral data the
   I2RS Agents.  Future I2RS work MAY support caching of data in the
   I2RS Agents.  Implementers are encourages to experiment with caching
   of ephemeral data in I2RS Agents.

4.2.  Protocol Security

   The I2RS protocol requires the ability to run over secure transport
   connections for the I2RS protocol to run over.  Each secure transport
   must provide data confidentiality, data integrity, and replay
   prevention.  NETCONF running over TLS or SSH over TCP, and RESTCONF
   running over HTTP 1.1 over TLS over TCP provide these features.
   However, the I2RS protocol requires extensions to this protocol
   security.  This section provides an overview these changes.

4.2.1.  Summary of Protocol Security Changes

   The I2RS protocol requires the following new security features:

   o  mutual identification of I2RS Client and Agents via unique
      identifiers,





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   o  the I2RS client identifier to be associated with a priority and a
      secondary identity

   o  data access (read/write) for each data model to be associated with
      I2RS client roles,

   o  the ability to send some data over an insecure section as
      specified in a data model.

   This section describes these new features.

4.2.1.1.  Multiple secure transports

   The I2RS protocol MAY operate over a set of secure transports (1 to
   many transports) which provide data confidentiality, data integrity,
   and replay prevention.  The key management that distributes keys MUST
   guarantee that only the entities having sufficient privileges can get
   the keys to encrypt/decrypt the sensitive data.  NETCONF's
   operatoring over TLS or SSH protocols, both of which run over TCP,
   provide such a secure transport as does RESTCONF operating over HTTP
   1.1 operating over TLS which runs over TCP also fits this
   description.

4.2.1.2.  Mutual Identification

   I2RS protocol security requires mutual identification of I2RS client
   and agent via a unique identifier.  The identity of each I2RS client
   must be represented by at least one unique I2RS client identifier,
   and the identity of an I2RS Agent must be represented by at least one
   unique I2RS agent identifier.  The I2RS protocol must perform mutual
   identification of the I2RS client and the I2RS agent.  The I2RS
   client-agent security association is valid for a single transport
   session or a set of parallel transport sessions.  The I2RS client-
   agent security association does not need to have an active transport
   session to remain active.  The I2RS agent and client unique
   identifiers are created and distributed outside the I2RS protocol.

4.2.1.3.  I2RS Client has Identifier + Priority + Secondary Identifier

   Each I2RS client identifier will have one priority and one secondary
   identifier during a particular I2RS transaction (read/write
   sequence), but the priority and the secondary identity associated
   with a I2RS client identity may change during a I2RS client-agent
   association.







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4.2.1.4.  I2RS Role Based Access

   Certain data within routing elements is sensitive and read/write
   operations on such data SHOULD be controlled as to which I2RS client
   can access the data for read/write based on the I2RS client's roles
   in order to protect its confidentiality.  A I2RS Client's role
   describe which data models and which data within those data models
   the I2RS client can have read access, write access, or both (read/
   write).

4.2.1.5.  Insecure Transport

   An I2RS data model with ephemeral state MAY require the passage of
   I2RS data will require the some data to be be sent from the I2RS
   agent to a I2RS client via an insecure transport.  Examples of this
   transport could be the I2RS agent agent opening up a TCP connection
   to an I2RS Client via TCP.  The yang data model specifying this MUST
   indicate what data is able to be passed over an insecure transport
   connection.  Insecure transport must still support traceability and
   publication/subscription of the insecure data.

4.3.  Data Flow

   Large amounts of data can flow from the I2RS agent to the I2RS
   client, or from the I2RS client to the I2RS Agent.  The I2RS client
   may set or query ephemeral configuration in the routing system via
   the I2RS agent and receive operational state, notifications, or
   logging from the I2RS Agent on behalf of the I2RS routing system.  In
   addition, some OAM functions engaged by the by the I2RS Client via
   the I2RS Agent can require large data flows plus system resources
   (cpu, memory, data storage).  This section discusses implementation
   issues regarding this work.

4.3.1.  Data Flow for Ephemeral Configuration

   The requirements for high performance and high-volune data flow
   between the I2RS Clients and the I2RS agents in the routing system
   have been described in general in the I2RS architecture
   [I-D.ietf-i2rs-architecture].  lients can send large amount of
   ephemeral configuration data to the I2RS Agent.  The writes may be
   done via NETCONF (<edit-config> or an rpc function), or via RESTCONF
   (PUT, PATCH, POST).  Reads can be done via NETCONF <get-config> or
   RESTCONF GET or query.

   The I2RS RIB Data Model [I-D.ietf-i2rs-rib-data-model] also supports
   the use of rpc to add/delete RIBs, add/delete/update routes, and add/
   delete nexthops.  If the I2RS client does a small to medium number of
   writes to the I2RS ephemeral state in the I2RS Agent in a routing



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   system, the full validation that NETCONF or RESTCONF does will be
   able to be done without any reduction in speed to the I2RS high-
   performance system.  For example, if the I2RS RIB Data Model has adds
   a 1000 routes, the I2RS RIB use of rpc to add/delete/update routes
   should be able to provide a high-performance system.  Alternatively
   the NETCONF <edit-config> could update these 1000 routes with a
   write, or the RESTCONF POST, PUT or PATCH should be able to add the
   1000 routes.

   If a large number of ephemeral routes or filters are written (updates
   or new) by the I2RS Client to the ephemeral state in the I2RS agent,
   one of the key issues for a high performance interface is the time it
   takes to validate routes.  Due to this concern, the I2RS architecture
   was design to allow less than the full NETCONF or RESTCONF
   validation.  The concept is that the I2RS routes would be validated
   within the I2RS client and sent via a 99.999% reliable connection.
   In this scenario, the I2RS Agent would trust the validation that the
   I2RS Client did, and the communication of the route additions via the
   network connection.

   An experiment regarding this has been done with the ODL code base
   update of ephemeral routes, but additional experimentation needs to
   be done prior to finalizing this design.  Section 3.4.2 reviews how
   this process might be done, but many open issues exist in
   implementing this "low-validation" interface.  Without additional
   experimentation and prototype code, this type of "low-validation",

4.3.2.  Write Error handling

   This section reviews I2RS normal error handling and error handling
   for rpc with no validation checks.

4.3.2.1.  Normal validation checks

   An I2RS agent validates an I2RS client's information by examining the
   following:

   o  message syntax validation,

   o  syntax validation for nodes of data model,

   o  referential checks (leafref checks MUST clauses, and instance
      indentifier),

   o  checks groups of data within a data model or groups of data across
      data models,

   o  write access to data,



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   o  if write access and values already exist, if I2RS client write
      access is higher than existing priority.

4.3.2.1.1.  Multiple I2RS Clients Write Same Node

   Multiple I2RS clients writing to the same variable is considered an
   "error condition" in the I2RS architecture
   [I-D.ietf-i2rs-architecture], but an 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.

   The I2RS protocol security requires that each I2RS client has a
   identity that has a unique identifier which has one priority and one
   secondary identitifer associated it during a write sequence (singel
   write or multiple group actions (see below).

   An I2RS client's unique identifier is distributed along with valid
   roles and a valid priority via exterior mechanisms (AAA,
   administrative interface) to the I2RS agent.  The secondary
   identifier is passed as an opaque meta value in the I2RS Client
   write.  The exterior mechanism may change the the valid roles and
   priority associated with an I2RS client's identifier.  If a change
   occurs after the I2RS client data has written information, the I2RS
   agent must revaluate the writes associate with this I2RS client
   (including rpcs).  The I2RS agent may schedule this evaluation, but
   it should provide the following notifications to the I2RS client:

      I2RS agent had received change of priority for I2RS client,

      I2RS agent is beginning reevaluation of writes or rpcs associated
      with the client due to priority change,

      I2RS agent has completed the revaluation due to priority change.

4.3.2.1.2.  Multiple Action Messages

   An I2RS agent receiving multiple action to write data within a
   message from an I2RS client must validate the data and check to make
   sure this I2RS client has permission and priority to change all the
   values.  If one of the values in the multiple action messages fails




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   one of these tests, then error handling must decide what to do with
   the rest of the values.

   Error handling in I2RS protocol version 1 simply remove all changed
   nodes and restores the previous values (all-or-nothing).  In this
   case, the short term ephemeral values are kept until the message is
   processed.

   Error handling on writes of the ephemeral datastore could be
   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, but the
   writes do not have to be "all-or-nothing."

   I2RS suggests the following are some of the potential error handling
   techniques for multiple message sent to the I2RS client:

   1.  Perform all or none: All operations succeed or none of them will
       be applied.  This useful when there are mutual dependencies.

   2.  Perform until error: Operations are applied in order, and when
       error occurs the processing stops.  This is useful when
       dependencies exist between multiple-message operations, and order
       is important.

   3.  Perform all storing errors: Perform all actions storing error
       indications for errors.  This method can be used when there are
       no dependencies between operations, and the client wants to sort
       it out.

   The initial version of I2SR protocol restricts I2RS protocol
   implementations to an "all or nothing" (aka roll-back on error).

   Is important to reliability of the data store that none of these
   error handling for multiple operations in one more multiple messages
   cause errors into be insert the I2RS ephemeral data-store.

   Discussion of Current NETCONF/RESTCONF versus

   RESTCONF does an atomic action within a http session, and NETCONF has
   atomic actions within a commit.  These features may be used to
   perform these features.

   I2RS processing is dependent on the I2RS model.  The I2RS model must
   consider the dependencies within multiple operations work within a
   model.




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4.3.2.1.2.1.  Grouping and Error handling

   Yang 1.1 provide the ability to group data in groupings, leafref
   lists, lists, and containers.  Grouping of data within a model links
   to data that is logically associated with one another.  Data models
   may logical group data across models.  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.

4.3.2.1.2.2.  Why All-or-Nothing

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

   RESTCONF has a complete set of operations per message.  The RESTCONF
   patch [I-D.ietf-netconf-yang-patch] could support partial edit
   functions per messages.

   Since version 1 of I2RS protocol desires to support NETCONF and
   RESTCONF equally, the partial

4.3.2.1.2.3.  Future Error Handling of Multiple Write Messages

   The [I-D.ietf-i2rs-architecture] specifies three types of error
   handling for a partial write operation of orthogonal data:

   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.)

   Grouped data must only use "all-or-nothing."

   Future I2RS protocol versions will mandate "stop-on-error" handling
   or "continue-on-error" handling of multiple orthongal actions if a
   RESTCONF "patch" like facility is defined for NETCONF.





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4.3.2.2.  Reduced Validation (Experimental)

   Note: It is not clear how reduced validation works handles all
   failures cases, so implementers are encouraged to experiment and
   report results.  The authors are concerned about the various failures
   scenarios.  One authors (Andy Bierman) raises concerns whether this
   can work with local configuration.

   As described above, in some circumstances the I2RS client-agent
   communication may be considered almost perfect (99.999%), and the
   speed of update critical.  In such cases, the operator may choose to
   have the I2RS client do all the validation within a group and between
   groups prior to downloading the data, and the I2RS agent to simply
   upload the data.  One mechanisms puts this function in an RPCs

4.3.2.2.1.  Reduced Validation RPC (Experimental)

   The "no validation" feature requires:

   o  operator-applied policy knob enabling this feature;

   o  rpc in a data model with the yang "ephemeral-validation no-check;"

4.3.3.  Data Flows From the I2RS Agent to I2RS Client

   Large data flows can be required by the I2RS agent to publish large
   data for protocol state, virtual topologies, events, and
   notifications from a routing system.
   [I-D.ietf-i2rs-pub-sub-requirements] specify the I2RS requirements
   for publication of large data flows from the I2RS Agent via a
   publication/subscription (aka pub-sub) mechanism.  The pub-sub
   mechanisms has been specified for the "push" service in
   [I-D.ietf-netconf-yang-push].

   Large data flows can also be required to trace the actions of a
   routing system.  These requirements are listed in the
   [I-D.ietf-i2rs-traceability].  These traceability requirements
   specify mandatory fields in the trace log including an end of message
   marker for a record plus handling of the trace logs.  This handling
   includes creation of trace logs, limits on trace logs, trace log
   rotation, and trace log retrieval by syslog [RFC5424], the pub-sub
   mechanism or a large data push.  This large data push can be a pull
   in a large write.

   Large data flows from the I2RS client also mean that some of the data
   flows from the I2RS Agent may be prioritized over other data flows
   (I2RS-DF-REQ-07).  This priorization will be based on what the data




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   is, what the operator-applied policy knobs are for reporting, and the
   current resource constraints (I2RS-DF-REQ-05).

4.3.4.  OAM Constraints

   OAM actions in a router may require extra processing, extra memory or
   data storage, or extra data flows to/from the I2RS agent.  The OAM
   functions SHOULD not impact the routing functions so it cannot
   perform its main task of guiding the traffic.  OAM functions must be
   able to be limited in terms of processing power, memory, data
   storage, or data flows to/from network (I2RS-DF-REQ-05).

4.3.5.  IPFIX for traffic monitoring

   Due to the potentially large data flow the traffic measurment
   statistics generate, these statistics are best handled by publication
   techniques within NETCONF or a separate protocol such as IPFIX.  In
   the future version of the I2RS protocol may desire to support a data
   stream outbound from the I2RS Agent to an I2RS client via the IPFIX
   protocol.

4.4.  Yang Changes

   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 Proposed changes to Yang for I2RS protocol version 1 are:

   o  i2rs:version 1;

   o  i2rs:transport-nonsecure ok;

   o  i2rs:ephemeral-validation nocheck;

   o  ephemeral true;

   o  encoding [XML | JSON]

   o  protocol [RESTCONF | NETCONF]

   o  protocol-transport [ssh, tls, tcp]

   o  transport-ports [ports]






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   Since ephemeral data store, encoding methods, protocols, protocol
   transport, and transport ports are features of the general protocols,
   these are not tagged with the "i2rs:" key word.

4.5.  Transport Protocol Changes

4.5.1.  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 HTTOS with (GET, POST, PUT, PATCH, DELETE,
   OPTIONS, and HEAD).

4.5.2.  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.

   [RFC6536] with extensions supporting ephemeral, non-secure transport,
   and rpcs with no validation checks might look like:

   extension ephemeral {
    description "if present in a data definition statement
       then the object is considered OK for editing as ephemeral data."
           }
   extension non-secure-ok {
     description "if present in data definition statement
      then the object is considered OK for non-secure transport."
      }
   extension ephemeral-validation-nocheck {
     description "if present in rpc definition
     the data received in the rpc is considered to
     not require validation checks.
      }

4.6.  NETCONF protocol extensions for the ephemeral datastore

   capability-name: ephemeral-datastore





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4.6.1.  Overview

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

   o  the ephemeral data store is a part of the intended configuration
      datastore, applied configuration datastore, and the derived state
      store whose components are not survive a reboot.

   o  The ephemeral capability is signalled as a capability of a leaf,
      grouping, a sub-module, or module that is stored as a feature of
      the module in the netconf yang module library
      ([I-D.ietf-netconf-yang-library]) used by Yang 1.1 and RESTCONF
      and NETCONF.

   o  ephemeral data will be noted by an "ephemeral" statement in for a
      leaf, grouping, sub-module, or module.

   o  The ephemeral datastore is never locked.

   o  The ephemeral data store is one pane of glass that overrides the
      local configuration (which is considered one pane of glass) in the
      intended config based on operator-applied policy knobs (see
      section 2.1).

   o  Ephemeral data 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 within the module.
      Ephemeral modules cannot have non-ephemeral sub-modules or nodes
      within the module.  Yang 1.1 [I-D.ietf-netmod-rfc6020bis]
      augmented by ephemeral state must enforce this restriction.
      Similarly, the Yang mount schema [I-D.ietf-netmod-schema-mount]
      must check for this restriction.

   o  Ephemeral writes should enforce the normal validation checks,
      priority pre-emption error handling if multiple I2RS clients write
      the same data, and "all-or-nothing" error handling for multiple
      actions in a write for data in groupings or orthogonal data (see
      section 3.4).  The I2RS agent should send the I2RS client
      requesting write the notification of any type of error during the
      write process: failure of normal validation, priority pre-emption
      causing failure to write, multiple actions causing failure to
      sustain write (aka all-or-nothing roll-back).  If the I2RS agent
      allows a priority pre-emption of the write of data model value by
      an I2RS client (e.g. client 1) of another I2RS client (e.g. client
      2), then the I2RS agent must send a notification of the I2RS pre-
      emption to the previous I2RS client (e.g. client 2).



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   o  Ephemeral writes as part of an rpc should allow the rpc to skip
      normal validation checks if data model specifies "ephemeral-
      validation nocheck;".  The rpc which skips the normal validation
      MUST resolve the pre-emption write error handling for any data
      being written without normal validation check, and MUST only all
      the data within a grouping rather than orthogonal data.

4.6.2.  Dependencies

   The following are the dependencies for ephemeral support:

   o  The Yang definitions specified in section 6.

   o  The Yang modules must support the event notification write and
      read errors as well as data model errors.

   o  The following features must be supported by NETCONF

      *  Call Home [I-D.ietf-netconf-call-home],

      *  Server Configuratino Module [I-D.ietf-netconf-server-model],

      *  Module library [I-D.ietf-netconf-yang-library],

      *  Publication/Subscription via Push [I-D.ietf-netconf-yang-push],

      *  Patch [I-D.ietf-netconf-yang-patch],

      *  syslog yang module (both [RFC5424] and
         [I-D.ietf-netmod-syslog-model]

4.6.3.  Capability identifier

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

4.6.4.  New Operations

   None

4.6.5.  Modification to existing operations

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







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4.6.5.1.  <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.

   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>

4.6.5.2.  <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.






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      <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 services in the pub/sub and traceability functions.

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

   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.

4.6.5.3.  <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>.






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4.6.5.4.  <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.

4.6.5.5.  <lock> and <unlock>

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

4.6.5.6.  <get>

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

4.6.5.7.  <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.

4.6.6.  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.  I2RS ephemeral state does not impact the writeable-
   running data store or the candiate config datastore.

4.6.6.1.  writable-running and candidate datastore

   The writeable-running and the candidate datastore cannot be used in
   conjunction with the ephemeral data store.  Ephemeral database
   overlays an intended configuration, and does not impact the writable-
   running or candidate data store.

4.6.6.2.  confirmed commmit

   Confirmed commit capability is not supported for the ephemeral
   datastore.








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4.6.6.3.  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).

4.6.6.4.  validate

   The validation function operates normally with one addition with one
   addition for any data handled by an rpc with "ephemeral-validation
   nocheck".

   The rpc specifying ephemeral-validation nocheck MUST specify within
   the ephemeral data written by the rpc function the following
   grouping:

     grouping ephemeral-validation-notcheck {
           leaf rpc {
             type string rpc-id;
             description "rpc wrote
              the non-check data";
           }
       leaf rpc-seq {
              type uint32 rpc-id;
              description "sequence number of
               rpc that wrote non-check data";
           }
       leaf client-id {
         type uint64 client-id;
             description "client identifier
              that wrote non-checking rpc;"
           }
       description "Tracking on rpc with
         no validation checking so validation
         failure can send note to client.";
     };


   If the data validation finds an error in a component that was non-
   check, the notification should include the data module, submodule (if
   valid).

   (Editor's note: Initial experiments on this type of rpc for I2RS RIB
   routes and I2RS FB-RIB filters will be done before IETF 96.








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4.6.6.5.  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.

4.6.6.6.  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 datastore.

4.7.  RESTCONF protocol extensions for the ephemeral datastore

   capability-name: ephemeral-datastore

4.7.1.  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.

4.7.2.  Dependencies

   The ephemeral capabilities have the following dependencies:

   o  The Yang definitions specified in section 6.

   o  The Yang modules must support the event notification write and
      read errors as well as data model errors.

   o  The following features must be supported by RESTCONF

      *  Call Home [I-D.ietf-netconf-call-home],

      *  Server Configuratino Module [I-D.ietf-netconf-server-model],

      *  Module library [I-D.ietf-netconf-yang-library],

      *  Publication/Subscription via Push [I-D.ietf-netconf-yang-push],

      *  Patch [I-D.ietf-netconf-yang-patch],

      *  syslog yang module (both [RFC5424] and
         [I-D.ietf-netmod-syslog-model]






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4.7.3.  Capability identifier

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

4.7.4.  New Operations

   none

4.7.5.  modification to data resources

   RESTCONF must be able to support the ephemeral datstore as a context
   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 strimgs can be
   done to determine the comparison of two I2RS client-priorities.

4.7.6.  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.

4.7.6.1.  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.

4.7.6.2.  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.

4.7.6.3.  GET changes

   GET must be able to read from the URL and a context
   ("?context=ephemeral").  Similarly, it is important the Get be able
   to determine if the context=ephemeral.




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4.7.6.4.  POST changes

   POST must simply be able to create resources in ephemeral datastores
   ("context=ephemeral") and invoke operations defined in ephemeral data
   models.

4.7.6.5.  PUT changes

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

4.7.6.6.  PATCH changes

   Plain PATCH must be able to update or create child resources in an
   ephemeral context ("?context=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.

4.7.6.7.  DELETE changes

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

4.7.6.8.  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 context
   ("?context=ephemeral") described above.

4.7.7.  Interactions with Notifications

   The ephemeral database must support the ability to publish
   notifications as events and the I2RS clients being able 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].

4.7.8.  Interactions with Error Reporting

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






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5.  Simple Thermostat Model

   In this discussion of ephemeral configuration, this draft utilizes a
   simple thermostat model with the YANG configuration found in figure
   6.  The desired-temp is local configuration node that has an
   ephemeral The actual temperature is a derived state node that records
   the actual temperature of the room.

   Figure 6 shows two I2RS clients.  I2RS client 1 has one connection to
   write the ephemeral copy of the desired temperature at priority 1.
   I2RS client 2 writes to the intended configuration with priority 10.
   I2RS client 1 has a second connetion to read the actual temperature,
   and I2RS client 2 also has a second connection to read the actual
   temperature.

   The NETCONF example shows a simple write of the ephemeral state value
   over the local configuration


































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    ...........     ...................    ...........
    :Candidate :---:running config    :--: start-up  :
    :          :   :desired-temp (cfg):  :           :
    ...........     ..................    ...........
                     |
                     |                        ==========
                     |                        |  I2RS  |
                     |                      +-|Client 1|
                     |                      | |=========
            .........|..................... |
   Intended . '''''''|''''''''''''''''''' . |  =========
    Config  . 'local config|ephemeral   '<--| |I2RS    |
            . 'desired-temp|desired-temp'<----|Client 2|
            . ''''''''''''|'''''''''''''' .    ==========
            ..............|................
                          |     read-write data
       -------------------|----------------------------------------
                              |     read only data
                          |
                    ======|======     ---------------
                    | Actual    |-----|I2RS client 1|
    Config true     | Config    |     ---------------
                    |  desired- |      |
                    |  temp     |==============
                    =============      |     ||
      ******************************** |     ||
    config false    | derived   |------+     ||
                    | state     |       ===============
                    |  actual-  |=======|I2RS Client 2 |
                    |  temp     |       ===============
                    -------------

    Policy Knob 1:Ephemeral overwrites local config (TRUE)
    Policy Knob 2:Updated local config overwrite ephemeral (FALSE)

   Figure 6 - Two I2RS clients

5.1.  YANG data model













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   module thermostat {
     ..
     leaf desired-temp {
        type int32;
            config true;
            ephemeral true;
            units "degrees Celsius";
            description "The desired temperature";
            }
     ....
     leaf actual-temp {
        type int32;
            config false;
            units "degrees Celsius";
            description "The measured
            temperature is derived state.
            }
     }
   Figure 6 - Simple thermostat YANG Model

   The changes in each step are shown in the figure 7.  In step 1, the
   running configuration desired-temp is change to 68 degress.  In step
   2, the intended configuration value for desired-temp is updated, and
   asynchronously the applied configuration is updated in step 4.  The
   actual temperature begins to rise to meet the desired temperature,
   and reaches it in step 4.  In step 5, I2RS client 1 update the
   intended configuration with a desired-temp=70.  In step 6 this value
   is updated to the applied configuration, and the actual temperature
   begins to rise (actual-temp = 69).  In step 7, the actual temperature
   has reached 70 degrees.  In step 8, I2RS Client 1 removes the
   ephemeral state from the intended configuration and the local
   configuration value is reasserted.  In step 9, the intended desired-
   temp is synchronously moved to applied configuration and the actual
   temperature drops.

















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   Step Running  Intended Config Applied Config  Derived
                                                 state
   ======================================================
    1  desired-                                  actual-
        temp=68                                  temp=65
   ------------------------------------------------------
    2   desired-  from running                   actual-
        temp=68   desired-temp                   temp=65
                  temp = 68
   ------------------------------------------------------
   3    Desired    Desired        Desired       Actual-
        temp=68    temp=68        temp=68       temp=67
   -------------------------------------------------------
   4    Desired    Desired        Desired        Actual-
        temp=68    temp=68        temp=68        temp=68
   ------------------------------------------------------
                   from I2RS
                   client 1
   5    Desired    Desired        Desired        Actual-
        temp=68    temp=70        temp=68        temp=68
   ------------------------------------------------------
   6    Desired    Desired        Desired        Actual-
        temp=68    temp=70        temp=70       temp=69
   ------------------------------------------------------
   7    Desired    Desired        Desired        Actual-
        temp=68    temp=70        temp=70       temp=70
   ------------------------------------------------------
                   I2RS client 1
                   removes state
   8    Desired    Desired        Desired        Actual-
        temp=68    temp=68        temp=70       temp=70
   -----------------------------------------------------
   9    Desired    Desired        Desired        Actual-
        temp=68    temp=68        temp=68        temp=68
   ======================================================

   Figure 7

   I2RS Client 1 handle the normal lowering and raising of the
   temperature during different time periods in the day.  I2RS Client 2
   has the ability for individuals to request the room warms up rapidly
   to a maximum of 72 degrees.  Figure 8 shows a simple example of the
   two clients interaction.  Steps 1-6 are the same as in figure 7.  In
   step 7, I2RS Client 2 sets the desired-temp in the intended
   configuration to 72.  In step 8, this intended configuration is
   passed to the applied configuration and the actual temperature
   reaches 72.




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   In step 9, I2RS client 2 removes its state.  The I2RS Client 1 is
   notified of the removal, and the I2RS Client 1 re-write the desired
   value of 70 degrees (desired-temp=70), and this is passed to the
   applied state.  The actual temperature drops to 70 degress (actual-
   temp=70).  In step 10, I2RS Client 1 removes its ephemeral state and
   desired-temp reverts to the local configuration value
   (desired=temp=68).  This value is installed in applied temperature
   and the actual temperature goes to 68 (actual-temp=68.)











































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   Step Running  Intended Config Applied Config  Derived
                                                 state
   ======================================================
    1  desired-                                  actual-
        temp=68                                  temp=65
   ------------------------------------------------------
    2   Desired   from running                   actual-
        temp=68   desired-temp                   temp=65
                  temp = 68
   ------------------------------------------------------
   3    Desired    Desired        Desired       Actual-
        temp=68    temp=68        temp=68       temp=67
   -------------------------------------------------------
   4    Desired    Desired        Desired        Actual-
        temp=68    temp=68        temp=68        temp=68
   ------------------------------------------------------
                   from I2rs
                                   client 1
   5    Desired    Desired        Desired        Actual-
        temp=68    temp=70        temp=68        temp=68
   ------------------------------------------------------
   6    Desired    Desired        Desired        Actual-
        temp=68    temp=70        temp=70       temp=69
   ------------------------------------------------------
                   I2RS Client 2
                   sets
   7    Desired    Desired        Desired        Actual-
        temp=68    temp=72        temp=70       temp=70
   ------------------------------------------------------
   8    Desired    Desired        Desired        Actual-
        temp=68    temp=72        temp=72       temp=72
   -----------------------------------------------------
                   I2RS client 2 removes state
                   reverts to I2RS client 1

   9    Desired    Desired        Desired        Actual-
        temp=68    temp=70        temp=70        temp=70
   -----------------------------------------------------
                   I2RS client 1 removes state

   10    Desired    Desired        Desired        Actual-
        temp=68    temp=68        temp=68        temp=68
   ======================================================

   Figure 8






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5.2.  NETCONF Changes

   The NETCONF way of writing the ephemeral data to the intended
   configuratino would be

   <rpc-message-id=101
     xmlns="urn:ietf:params:xml:ns:base:1.0">
     <edit-config>
       <target>
        <ephemeral >
               true
            </ephemeral >
       </target>
       <config>
         <top xmlsns="http:://example.com/schema/1.0/thermostat/config>
          <desired-temp> 70 </desired-temp>
         </top>
       </config>
      </edit-config>
   </rpc>

   figure 9 NETCONF setting of desired-temp

5.3.  RESTCONF Initial Write

   Figure 10 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 ephemeral datastore

   PUT /restconf/data/thermostat:desired-temp?context=ephemeral
   {"desired-temp":19 }

   Figure 8 - RESTCONF setting of ephemeral state

6.  Simple Route Add

   In this discussion of ephemeral configuration, this draft utilizes
   the I2RS RIB data model [I-D.ietf-i2rs-rib-data-model] where one
   client adds an route via a rpc to the I2RS ephemeral data model.

   Figure 9 shows two I2RS clients.  I2RS client 1 writes ephemeral
   routes with priority 1, and I2RS client 2 writes ephemeral routes
   with priority 5.  I2RS Client 1 and I2RS client can read the I2RS RIB
   With its status of installation.  For ease of display the I2RS client
   1 is show as two separate boxes, but these boxes are logically one
   client.  Client 2 is also shown as two boxes, but has only one box.



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    ...........     ...................    ...........
    :Candidate :---:running config    :--: start-up  :
    :          :   :desired-temp (cfg):  :           :
    ...........     ..................    ...........
                     |
                     |                      ==========
                     |                      |  I2RS  |
                     |                    +-|Client 1|
                     |                    | |=========
            .........|................... |
   Intended . '''''''|''''''''''''''''' . |  =========
    Config  . 'local config|ephemeral '<--| |I2RS    |
            . '   route    | route    '<----|Client 2|
            . ''''''''''''|''''''''''' .    ==========
            ..............|.............
                                  read-write data
       ------------------------------------------------------------
                            |     read only data
                            |
                    =============     ---------------
                    | Actual    |-----|I2RS client 1|
    Config true     | Config    |     ---------------
                    |  route    |      |
                    |           |==============
                    =============      |     ||
      ******************************** |     ||
    config false    | derived   |------+     ||
                    | state     |       ===============
                    |  route    |=======|I2RS Client 2 |
                    |  active   |       ===============
                    -------------

   Policy Knob 1:Ephemeral overwrites local config (TRUE)
   Policy Knob 2:Updated local config overwrite ephemeral (FALSE)

   Figure 11 - Two I2RS clients

   Figure 10 shows the addition of routes to a IPv4 RIB using the rpc-
   add route function in the I2RS RIB [I-D.ietf-i2rs-rib-data-model].
   Step 1 shows the route being configured via netconf as a static
   route, and step 2 shows how this static route is installed in the
   intended configuration.  Step 3 shows how this static route is
   installed in the applied configuration and the derived status
   "installed" is added to the routing devices route table.  Step 4
   shows how the I2RS Client 1 adds the same route with a different next
   hop.  In this example, there is only one nexthop per route so the
   ephemeral route replaces static route configuration and is
   synchronously installed in the applied configuration.  Due to the



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   installation, the "installed" state is recorded in the kernel and
   associated with the I2RS RIB route.

   In step 5, I2RS client 2 adds the same route to the intended
   configuration with a different next hop which replaces the route
   added by I2RS client 1 because I2RS Client 2 has a higher priority
   that client 1.

   In step 6, I2RS client 2 removes the route.  and the I2RS client 1 is
   notified of the removal.  The I2RS client 1 re-write the route with a
   nexthop of 192.11.1.2, and the applied configuration is updasted.

   In step 7, the I2RS Client 1 removes route and the local
   configuration is restored in the intended configuration.  The
   intended configuration sent to applied configuration as part of the
   restoration.


   Step Running  Intended Config Applied Config  Derived
                                                 state
   ======================================================
   1    route=
        128.2/16
            nexthop=
            192.11.1.1
   ------------------------------------------------------
   2    route=      route=
        128.2/16    128.2/16
        nexthop=    nexthop=
        192.11.1.1  192.11.1.1
   ------------------------------------------------------
   3    route=      route=        route=          route-
        128.2/16    128.2/16      128.2/16        128.2/16
        nexthop=    nexthop=      nexthop=        nexthop=
        192.11.1.1  192.11.1.1    192.11.1.1      192.11.1.1
                                                  status-installed
   -------------------------------------------------------
                    I2RS
                                    client 1
                                    rpc route-add
   4    route=      route=        route=          route-
        128.2/16    128.2/16      128.2/16        128.2/16
        nexthop=    nexthop=      nexthop=        nexthop=
        192.11.1.1  192.11.1.2    192.11.1.2     192.11.1.2
                                                      status-installed
   ---------------------------------------------------------------
                   from I2RS client 2




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   5    route=      route=        route=          route-
        128.2/16    128.2/16      128.2/16        128.2/16
        nexthop=    nexthop=      nexthop=        nexthop=
        192.11.1.1  192.11.1.3    192.11.1.3     192.11.1.3
                                                      status-installed
   ---------------------------------------------------------------
                    I2RS Client2 removes route
                    and I2RS agent notifies
                    I2RS Client of change.
                    I2RS client 1 re-writes route.

   6    route=      route=        route=          route-
        128.2/16    128.2/16      128.2/16        128.2/16
        nexthop=    nexthop=      nexthop=        nexthop=
        192.11.1.1  192.11.1.2    192.11.1.2     192.11.1.2
                                                      status-installed
   ---------------------------------------------------------------
                    I2RS client 1
                    removes route
                    local configuration is restored

   7    route=      route=        route=          route-
        128.2/16    128.2/16      128.2/16        128.2/16
            nexthop=    nexthop=      nexthop=        nexthop=
            192.11.1.1  192.11.1.1    192.11.1.1      192.11.1.1
                                                      status-installed
   ================================================================

   Figure 12

6.1.  Portions of I2RS YANG data model




















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   module I2rs-RIB {
     ..
   module i2rs-rib {
        container routing-instance {
         ...
          list rib-list {
           ...
              list route-list {
                  key "route-index";
                  uses route;
             }
        }

     ....
      grouping route  {
           description
             "The common attribute used for all routes;"
            uses routeg-prefix;
             container nexthop {
                      uses nexthop;
                  }
              container route-statistics {
                  leaf route-state {
                     type route-state-def;
                     config false;    /* operational state */
                   }
                 leaf route-installed state {
                     type route-installed-state def;
                     config false;
                    }
                 leaf route-reason {
                   type route-reason-def;
                    config false;
                  }
              }
          container router-attributes {
               uses router-attributes;
            }
         container route-vendor-attributes
              uses route-vendor attributes;
        }
     }
   Figure 13 - Simplified I2RS Route Model








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6.2.  NETCONF Changes

   The NETCONF way of writing the ephemeral I2RS data would be:

    (TBD)

    Figure 14

6.3.  RESTCONF Changes

   Figure 8 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 ephemeral datastore

   (TBD)

   Figure 15 - RESTCONF Route change

7.  Previously Considered Ideas

7.1.  A Separate Ephemeral Data store

   The primary advantage of a fully separate data store is that the
   semantics of its contents are always clearly ephemeral.  It also
   provides strong segregation of I2RS configuration and operational
   state from the rest of the system within the network element.

   The most obvious disadvantage of such a fully separate data store is
   that interaction with the network element's operational or
   configuration state becomes significantly more difficult.  As an
   example, a BGP I2RS use case would be the dynamic instantiation of a
   BGP peer.  While it is readily possible to re-use any defined
   groupings from an IETF-standardized BGP module in such an I2RS
   ephemeral data store's modules, one cannot currently reference state
   from one data store to another

   For example, XPath queries are done in the context document of the
   data store in question and thus it is impossible for an I2RS model to
   fulfil a "must" or "when" requirement in the BGP module in the
   standard data stores.  To implement such a mechanism would require
   appropriate semantics for XPath.








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7.2.  Panes of Glass/Overlay

   I2RS ephemeral configuration state is generally expected to be
   disjoint from persistent configuration.  In some cases, extending
   persistent configuration with ephemeral attributes is expected to be
   useful.  A case that is considered potentially useful but problematic
   was explored was the ability to "overlay" persistent configuration
   with ephemeral configuration.

   In this overlay scenario, persistent configuration that was not
   shadowed by ephemeral configuration could be "read through".

   There were two perceived disadvantages to this mechanism:

      The general complexity with managing the overlay mechanism itself.

      Consistency issues with validation should the ephemeral state be
      lost, perhaps on reboot.  In such a case, the previously shadowed
      persistent state may no longer validate.

8.  IANA Considerations

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

9.  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.

10.  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




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   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

11.  Major Contributors

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

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

   o  Russ White (Linkedin)

12.  List of I2RS Requirements

   The I2RS protocol requirements which include requirements for:

   o  ephemeral state ([I-D.ietf-i2rs-ephemeral-state]),

   o  protocol security
      ([I-D.ietf-i2rs-protocol-security-requirements]),

   o  traceability ([I-D.ietf-i2rs-traceability]

   o  publication and subscription service
      ([I-D.ietf-i2rs-pub-sub-requirements],

   The I2RS environment requirments are find on
   [I-D.ietf-i2rs-security-environment-reqs].

13.  References







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13.1.  Normative References:

   [I-D.kwatsen-netmod-opstate]
              Watsen, K., Bierman, A., Bjorklund, M., and J.
              Schoenwaelder, "Operational State Enhancements for YANG,
              NETCONF, and RESTCONF", draft-kwatsen-netmod-opstate-02
              (work in progress), February 2016.

   [I-D.schoenw-netmod-revised-datastores]
              Schoenwaelder, J., "A Revised Conceptual Model for YANG
              Datastores", draft-schoenw-netmod-revised-datastores-01
              (work in progress), June 2016.

   [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>.

   [RFC4107]  Bellovin, S. and R. Housley, "Guidelines for Cryptographic
              Key Management", BCP 107, RFC 4107, DOI 10.17487/RFC4107,
              June 2005, <http://www.rfc-editor.org/info/rfc4107>.

   [RFC4960]  Stewart, R., Ed., "Stream Control Transmission Protocol",
              RFC 4960, DOI 10.17487/RFC4960, September 2007,
              <http://www.rfc-editor.org/info/rfc4960>.

   [RFC5339]  Le Roux, JL., Ed. and D. Papadimitriou, Ed., "Evaluation
              of Existing GMPLS Protocols against Multi-Layer and Multi-
              Region Networks (MLN/MRN)", RFC 5339,
              DOI 10.17487/RFC5339, September 2008,
              <http://www.rfc-editor.org/info/rfc5339>.

   [RFC5424]  Gerhards, R., "The Syslog Protocol", RFC 5424,
              DOI 10.17487/RFC5424, March 2009,
              <http://www.rfc-editor.org/info/rfc5424>.

   [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>.






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   [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>.

   [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>.

   [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>.

   [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>.

13.2.  Informative References

   [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-15 (work in
              progress), April 2016.

   [I-D.ietf-i2rs-ephemeral-state]
              Haas, J. and S. Hares, "I2RS Ephemeral State
              Requirements", draft-ietf-i2rs-ephemeral-state-14 (work in
              progress), July 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-06 (work in progress), May 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-09 (work in progress), May 2016.






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   [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-06 (work in progress), July
              2016.

   [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-09 (work
              in progress), July 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-01 (work in progress), April 2016.

   [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-11 (work
              in progress), May 2016.

   [I-D.ietf-netconf-call-home]
              Watsen, K., "NETCONF Call Home and RESTCONF Call Home",
              draft-ietf-netconf-call-home-17 (work in progress),
              December 2015.

   [I-D.ietf-netconf-restconf]
              Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", draft-ietf-netconf-restconf-15 (work in
              progress), July 2016.

   [I-D.ietf-netconf-server-model]
              Watsen, K. and J. Schoenwaelder, "NETCONF Server and
              RESTCONF Server Configuration Models", draft-ietf-netconf-
              server-model-09 (work in progress), March 2016.

   [I-D.ietf-netconf-yang-library]
              Bierman, A., Bjorklund, M., and K. Watsen, "YANG Module
              Library", draft-ietf-netconf-yang-library-06 (work in
              progress), April 2016.

   [I-D.ietf-netconf-yang-patch]
              Bierman, A., Bjorklund, M., and K. Watsen, "YANG Patch
              Media Type", draft-ietf-netconf-yang-patch-10 (work in
              progress), July 2016.




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   [I-D.ietf-netconf-yang-push]
              Clemm, A., Prieto, A., Voit, E., Tripathy, A., and E.
              Nilsen-Nygaard, "Subscribing to YANG datastore push
              updates", draft-ietf-netconf-yang-push-03 (work in
              progress), June 2016.

   [I-D.ietf-netconf-zerotouch]
              Watsen, K. and M. Abrahamsson, "Zero Touch Provisioning
              for NETCONF or RESTCONF based Management", draft-ietf-
              netconf-zerotouch-09 (work in progress), July 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-rfc6020bis]
              Bjorklund, M., "The YANG 1.1 Data Modeling Language",
              draft-ietf-netmod-rfc6020bis-14 (work in progress), June
              2016.

   [I-D.ietf-netmod-schema-mount]
              Bjorklund, M. and L. Lhotka, "YANG Schema Mount", draft-
              ietf-netmod-schema-mount-02 (work in progress), July 2016.

   [I-D.ietf-netmod-syslog-model]
              Wildes, C. and K. Koushik, "Syslog YANG Model", draft-
              ietf-netmod-syslog-model-09 (work in progress), July 2016.

   [I-D.ietf-netmod-yang-metadata]
              Lhotka, L., "Defining and Using Metadata with YANG",
              draft-ietf-netmod-yang-metadata-07 (work in progress),
              March 2016.

   [I-D.wilton-netmod-refined-datastores]
              Wilton, R., "Refined YANG datastores", draft-wilton-
              netmod-refined-datastores-01 (work in progress), July
              2016.

Authors' Addresses

   Susan Hares
   Huawei
   Saline
   US

   Email: shares@ndzh.com




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   Amit Daas
   Ericsson

   Email: amit.dass@ericsson.com















































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