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

Versions: 00 draft-ietf-lmap-restconf

Network Working Group                                   J. Schoenwaelder
Internet-Draft                                                 V. Bajpai
Intended status: Standards Track                Jacobs University Bremen
Expires: September 27, 2015                               March 26, 2015


              Using RESTCONF with LMAP Measurement Agents
                   draft-schoenw-lmap-restconf-00.txt

Abstract

   This document describes how RESTCONF can be used with a YANG data
   model for Large-Scale Measurement Platforms (LMAP).

Status of This Memo

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

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

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

   This Internet-Draft will expire on September 27, 2015.

Copyright Notice

   Copyright (c) 2015 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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






Schoenwaelder & Bajpai Expires September 27, 2015               [Page 1]


Internet-Draft               LMAP Data Model                  March 2015


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Overview of RESTCONF  . . . . . . . . . . . . . . . . . . . .   2
   3.  RESTCONF as LMAP Control Protocol . . . . . . . . . . . . . .   3
   4.  RESTCONF as LMAP Report Protocol  . . . . . . . . . . . . . .   3
   5.  Conclusion  . . . . . . . . . . . . . . . . . . . . . . . . .   4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   8.  Informative References  . . . . . . . . . . . . . . . . . . .   4
   Appendix A.  Response to Protocol Comparison Criteria . . . . . .   5
   Appendix B.  Example RESTCONF Control Protocol Exchange . . . . .   7
   Appendix C.  Example RESTCONF Report Protocol Exchange  . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   This document discusses how a controller can use the RESTCONF
   protocol [I-D.ietf-netconf-restconf] to configure Large-Scale
   Measurement of Broadband Performance (LMAP) measurement agents (MAs)
   [I-D.ietf-lmap-framework].  It also discusses how RESTCONF can be
   used to report measurement results to a collector.

   MAs may be deployed as separate hardware devices or as functions
   embedded in consumer electronic devices and home routers or as pure
   software solutions that can be installed on off-the-shelf computing
   equipment.  Measurement agents receive instructions from a controller
   about when and how to conduct what measurements (the measurement
   schedule) and how and when to report measurement results to a data
   collector (the report schedule).  Further information about the
   interaction between MAs and controllers and collectors can be found
   in [I-D.ietf-lmap-framework].

   The LMAP information model [I-D.ietf-lmap-information-model] defines
   the information exchanged between a controller and an MA and the
   information exchanged between an MA and a collector.  An information
   model is conceptual and protocol-independent.  A concrete YANG
   [RFC6020] data model derived from the conceptual information model is
   defined in [I-D.schoenw-lmap-yang].

2.  Overview of RESTCONF

   The RESTCONF protocol [I-D.ietf-netconf-restconf] provides a REST-
   like interface to access and manipulate a so-called unified YANG
   datastore [RFC6020].  The basic idea behind RESTCONF is expose a YANG
   datastores as a collection of Web resources that can be manipulated
   using standard HTTP [RFC7230] DELETE, PATCH, POST, and PUT methods.




Schoenwaelder & Bajpai Expires September 27, 2015               [Page 2]


Internet-Draft               LMAP Data Model                  March 2015


   The resource hierarchy is derived from the nesting structure of the
   YANG schema tree, leading to a so called data model driven REST API.

   RESTCONF is essentially a convention how to use HTTP over TLS to
   access a datastore that has a structure defined by a YANG data model.
   The data is exchanged in XML encoding or JSON encoding.

   The normal mode of operation is that the RESTCONF client initiates a
   secure transport to the RESTCONF server.  For devices located behind
   a NAT, a so called 'call-home' mechanism has been defined
   [I-D.ietf-netconf-call-home] that enables the RESTCONF server to
   establish a secure transport to a RESTCONF client.  Note that call
   home only changes the TCP connection establishment, the TLS and HTTP
   client/server roles do not change.  The policy used to call home can
   be configured through a configuration data model
   [I-D.ietf-netconf-server-model].  This model provides mechanism to
   configure a list of redundant endpoints and it provides control over
   call-home policies (e.g, call-home frequency, idle-timers, keep-alive
   timers).

3.  RESTCONF as LMAP Control Protocol

   It is straight-forward to user RESTCONF as a control protocol.  The
   YANG data model [I-D.schoenw-lmap-yang] derived from the underlying
   information model [I-D.ietf-lmap-information-model] translates into a
   collection of RESTCONF resources that can be manipulated at various
   levels of granularity using DELETE, PATCH, POST, and PUT methods.

   An example exchange showing a REST call to create a schedule object
   is shown in Appendix B.

4.  RESTCONF as LMAP Report Protocol

   One way of mapping the information model parts relevant for reports
   into a YANG data model is the usage of YANG notifications.  This is
   the approach currently used in [I-D.schoenw-lmap-yang].  This mapping
   leads to report notifications that push measurement results from the
   MA to a collector.  The RESTCONF protocol uses Server Sent Events as
   the underlying mechanism to stream notifications.

   A direct mapping of the information model leads to relatively verbose
   exchanges and it is possible to define more space efficient
   notifications that suppress information that is only changing rarely.

   An example exchange of a result notification is shown in Appendix C.

   Note that alternative designs are possible.  One option is to make
   the collector a RESTCONF server and to have the MA push results to



Schoenwaelder & Bajpai Expires September 27, 2015               [Page 3]


Internet-Draft               LMAP Data Model                  March 2015


   the collector by posting to resources on the controller.  Another
   option is to have the results reside on the MA and to export the
   results as part of the operational state of the MA.  The collector(s)
   will then use GET requests to fetch the result resources from the MA.
   Note that all three approaches can be implemented using RESTCONF and
   YANG.

5.  Conclusion

   This document discusses how RESTCONF can be used as a control
   protocol and a report protocol for Large-Scale Measurement Platforms
   (LMAP).  The benefit of using RESTCONF is that no new protocol work
   needs to be done.  Additional benefits derive from using YANG and a
   data model driven approach.  Despite the reuse of existing tools,
   using a data model driven approach allows to easily reuse other data
   models (e.g., network interfaces [RFC7223], [RFC7277] or general
   system services [RFC7317]) in order to export additional status
   information about an MA to a controller.

6.  IANA Considerations

   This document has no requests for IANA.

7.  Acknowledgements

   Juergen Schoenwaelder and Vaibhav Bajpai work in part on the Leone
   research project, which receives funding from the European Union
   Seventh Framework Programme [FP7/2007-2013] under grant agreement
   number 317647.

8.  Informative References

   [I-D.ietf-lmap-framework]
              Eardley, P., Morton, A., Bagnulo, M., Burbridge, T.,
              Aitken, P., and A. Akhter, "A framework for Large-Scale
              Measurement of Broadband Performance (LMAP)", draft-ietf-
              lmap-framework-12 (work in progress), March 2015.

   [I-D.ietf-lmap-information-model]
              Burbridge, T., Eardley, P., Bagnulo, M., and J.
              Schoenwaelder, "Information Model for Large-Scale
              Measurement Platforms (LMAP)", draft-ietf-lmap-
              information-model-04 (work in progress), March 2015.

   [I-D.ietf-netconf-call-home]
              Watsen, K., "NETCONF Call Home and RESTCONF Call Home",
              draft-ietf-netconf-call-home-04 (work in progress),
              February 2015.



Schoenwaelder & Bajpai Expires September 27, 2015               [Page 4]


Internet-Draft               LMAP Data Model                  March 2015


   [I-D.ietf-netconf-restconf]
              Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", draft-ietf-netconf-restconf-04 (work in
              progress), January 2015.

   [I-D.ietf-netconf-server-model]
              Watsen, K. and J. Schoenwaelder, "NETCONF Server and
              RESTCONF Server Configuration Models", draft-ietf-netconf-
              server-model-06 (work in progress), February 2015.

   [I-D.schoenw-lmap-yang]
              Schoenwaelder, J. and V. Bajpai, "A YANG Data Model for
              LMAP Measurement Agents", draft-schoenw-lmap-yang-02 (work
              in progress), January 2015.

   [I-D.starkcarey-lmap-protocol-criteria]
              Stark, B. and T. Carey, "LMAP Protocol Selection
              Criteria", draft-starkcarey-lmap-protocol-criteria-01
              (work in progress), March 2015.

   [RFC6020]  Bjorklund, M., "YANG - A Data Modeling Language for the
              Network Configuration Protocol (NETCONF)", RFC 6020,
              October 2010.

   [RFC7223]  Bjorklund, M., "A YANG Data Model for Interface
              Management", RFC 7223, May 2014.

   [RFC7230]  Fielding, R. and J. Reschke, "Hypertext Transfer Protocol
              (HTTP/1.1): Message Syntax and Routing", RFC 7230, June
              2014.

   [RFC7277]  Bjorklund, M., "A YANG Data Model for IP Management", RFC
              7277, June 2014.

   [RFC7317]  Bierman, A. and M. Bjorklund, "A YANG Data Model for
              System Management", RFC 7317, August 2014.

Appendix A.  Response to Protocol Comparison Criteria

   A set of control and report protocol comparison criteria has been
   defined in [I-D.starkcarey-lmap-protocol-criteria].  This section
   compares the usage of RESTCONF against the criteria.

   CP-MUST-1   yes (RFC6241 RFC6242, RFC5539),
               [I-D.ietf-netconf-restconf]

   CP-MUST-2   yes [I-D.ietf-netconf-call-home]




Schoenwaelder & Bajpai Expires September 27, 2015               [Page 5]


Internet-Draft               LMAP Data Model                  March 2015


   CP-MUST-3   yes SSH / TLS (NETCONF), TLS (RESTCONF)

   CP-MUST-4   yes YANG data models [RFC6020] have a well defined
               versioning and extension model

   CP-DIFF-1   1

   CP-DIFF-2   1

   CP-DIFF-3   yes

   CP-DIFF-4   yes (NETCONF|RESTCONF) call home

   CP-DIFF-5   (underspecified - it is JSON or XML over HTTP/TLS)

   CP-DIFF-6   (underspecified - it is JSON or XML over HTTP/TLS)

   CP-DIFF-7   HTTP and JSON/XML are pretty much everywhere

   CP-DIFF-8   YANG tools are out there and the rest will develop, HTTP
               and TLS are pretty well understood

   CP-DIFF-9   yes

   CP-DIFF-10  many tools out there to create REST code, YANG tools
               available

   CP-DIFF-11  yes, YANG RFC 6020 data models have a version model

   CP-DIFF-12  additional YANG modules can augment the standard data
               model

   CP-DIFF-13  JSON and XML, CBOR in the making

   RP-MUST-1   yes [I-D.ietf-netconf-call-home]

   RP-MUST-2   SSH / TLS (NETCONF), TLS (RESTCONF)

   RP-MUST-3   YANG RFC 6020 data models have a version model

   RP-DIFF-1   TCP

   RP-DIFF-2   yes

   RP-DIFF-3   (underspecified - it is HTTP over TLS)

   RP-DIFF-4   yes




Schoenwaelder & Bajpai Expires September 27, 2015               [Page 6]


Internet-Draft               LMAP Data Model                  March 2015


   RP-DIFF-5   yes

   RP-DIFF-6   yes (as part of HTTP encoding negotiations)

   RP-DIFF-7   (underspecified - it is JSON or XML over HTTP/TLS)

   RP-DIFF-8   HTTP and JSON/XML are pretty much everywhere

   RP-DIFF-9   many tools out there to create REST code, YANG tools
               available

   RP-DIFF-10  yes

   RP-DIFF-11  many tools out there to create REST code, YANG tools
               available

   RP-DIFF-12  JSON and XML, CBOR in the making




Appendix B.  Example RESTCONF Control Protocol Exchange

   Below is a YANG tree diagram of a part of the data model covering
   schedules.  This is taken from [I-D.schoenw-lmap-yang].


   module: ietf-lmap
      +--rw lmap
         +--rw schedules
            +--rw schedule* [name]
               +--rw name      string
               +--rw action* [name]
               |  +--rw name           string
               |  +--rw task           leafref
               |  +--rw option* [name]
               |  |  +--rw name     string
               |  |  +--rw value?   string
               |  +--rw destination* [name]
               |     +--rw name        string
               |     +--rw output*     uint16
               |     +--rw schedule    leafref
               |     +--rw action      leafref
               +--rw timing    leafref


   Below is an XML representation of instance data conforming to the
   YANG data model is shown below.  Note that some of the strings are



Schoenwaelder & Bajpai Expires September 27, 2015               [Page 7]


Internet-Draft               LMAP Data Model                  March 2015


   references to other portions of the instance data not show here.
   This is again taken from [I-D.schoenw-lmap-yang].


     <lmap xmlns="urn:ietf:params:xml:ns:yang:ietf-lmap">
       <schedules>
         <schedule>
           <name>hourly</name>
           <action>
             <name>icmp-latency-hourly</name>
             <task>icmp-latency-measurement</task>
             <destination>
               <name>q-all</name>
               <schedule>daily</schedule>
               <action>report-daily</action>
             </destination>
           </action>
           <timing>hourly</timing>
         </schedule>
       </schedules>
     </lmap>


   Below is an example showing how RESTCONF can be used to create the
   above schedule.  The prefix C: indicates the controller, the prefix
   M: indicates the measurement agent.  This example uses a JSON
   encoding (and note that much of the white-space can be removed, this
   is only there to help with readability).























Schoenwaelder & Bajpai Expires September 27, 2015               [Page 8]


Internet-Draft               LMAP Data Model                  March 2015


  C: POST /restconf/data/ietf-lmap:lmap/schedules HTTP/1.1
  C: Host: example.com
  C: Content-Type: application/yang.data+json
  C:
  C:   {
  C:     "ietf-lmap:schedule": {
  C:       "name": "hourly",
  C:       "action": [
  C:         {
  C:           "name": "icmp-latency-hourly",
  C:           "task": "icmp-latency-measurement",
  C:           "destination": [
  C:             {
  C:               "name": "q-all",
  C:               "schedule": "daily",
  C:               "action": "report-daily"
  C:             }
  C:           ]
  C:         }
  C:       ],
  C:       "timing": "hourly"
  C:     }
  C:   }

  M: HTTP/1.1 201 Created
  M: Date: Mon, 23 Apr 2012 17:01:00 GMT
  M: Server: example-server
  M: Location: https://example.com/restconf/data/ietf-lmap:lmap/schedules/schedule=hourly
  M: Last-Modified: Mon, 23 Apr 2012 17:01:00 GMT
  M: ETag: b3a3e673be2


Appendix C.  Example RESTCONF Report Protocol Exchange

   The first step taken by the collector is to lookup the event stream
   resource.















Schoenwaelder & Bajpai Expires September 27, 2015               [Page 9]


Internet-Draft               LMAP Data Model                  March 2015


  C: GET /restconf/data/ietf-restconf-monitoring:restconf-state/streams/stream=NETCONF/encoding=xml/events HTTP/1.1
  C: Host: example.com
  C: Accept: application/yang.data+xml

  M: HTTP/1.1 200 OK
  M: Content-Type: application/yang.api+xml
  M:
  M: <events
  M:  xmlns="urn:ietf:params:xml:ns:yang:ietf-restconf-monitoring">
  M:  https://example.com/streams/NETCONF
  M: </events>


   Once the event stream resource is known (information might be
   cached), the collector subscribes to the event stream resource.




































Schoenwaelder & Bajpai Expires September 27, 2015              [Page 10]


Internet-Draft               LMAP Data Model                  March 2015


     C: GET /streams/NETCONF HTTP/1.1
     C: Host: example.com
     C: Accept: text/event-stream
     C: Cache-Control: no-cache
     C: Connection: keep-alive

     M: data: <notification
     M: data:    xmlns="urn:ietf:params:xml:ns:yang:ietf-restconf">
     M: data:    <event-time>2013-12-21T00:01:00Z</event-time>
     M: data:    <report xmlns="urn:ietf:params:xml:ns:yang:ietf-lmap">
     M: data:    </report>
     M: data:

     M: data: {
     M: data:    "ietf-restconf:notification": {
     M: data:      "event-time": "2015-02-25T00:01:00Z",
     M: data:      "ietf-lmap:report": {
     M: data:         "date": "2015-02-25T00:01:00Z",
     M: data:         "agent-id": "xxx",
     M: data:         "header": {
     M: data:           "column": "target",
     M: data:           "column": "rtt"
     M: data:         }
     M: data:         "row": {
     M: data:           "start": "2015-02-25T00:01:00Z",
     M: data:           "value": "192.0.2.1",
     M: data:           "value": 42
     M: data:         }
     M: data:         "row": {
     M: data:           "start": "2015-02-25T00:01:00Z",
     M: data:           "value": "192.0.2.2",
     M: data:           "value": 24
     M: data:         }
     M: data:      }
     M: data:    }
     M: data: }


Authors' Addresses

   Juergen Schoenwaelder
   Jacobs University Bremen

   Email: j.schoenwaelder@jacobs-university.de







Schoenwaelder & Bajpai Expires September 27, 2015              [Page 11]


Internet-Draft               LMAP Data Model                  March 2015


   Vaibhav Bajpai
   Jacobs University Bremen

   Email: v.bajpai@jacobs-university.de















































Schoenwaelder & Bajpai Expires September 27, 2015              [Page 12]


Html markup produced by rfcmarkup 1.121, available from https://tools.ietf.org/tools/rfcmarkup/