<?xml version="1.0" encoding="US-ASCII"?>
<!DOCTYPE rfc SYSTEM "rfc2629.dtd">
<?rfc toc="no"?>
<?rfc tocompact="no"?>
<?rfc tocdepth="6"?>
<?rfc symrefs="yes"?>
<?rfc sortrefs="yes"?>
<rfc category="std" docName="draft-mahesh-netconf-persistent-00"
     ipr="trust200902">
  <front>
    <title abbrev="Persistent NETCONF">NETCONF and persistent
    responses</title>

    <author fullname="Mahesh Jethanandani" initials="M.J."
            surname="Jethanandani">
      <organization>Ciena Corporation</organization>

      <address>
        <postal>
          <street>3939 North 1st Street</street>

          <city>San Jose</city>

          <region>CA</region>

          <code>95134</code>

          <country>USA</country>
        </postal>

        <phone>408.904.2160</phone>

        <facsimile>408.436.5582</facsimile>

        <email>mjethanandani@gmail.com</email>

        <uri/>
      </address>
    </author>

    <date day="27" month="October" year="2014"/>

    <abstract>
      <t>This document outlines a solution for NETCONF operations that might
      be initiated with a single request but require multiple responses to be
      received, with an ability to terminate the operation at any time.</t>
    </abstract>
  </front>

  <middle>
    <section title="Introduction">
      <t><xref target="RFC6241">NETCONF</xref> protocol is being positioned as
      a replacement for Command Line Interface (CLI) and Simple Network
      Management Protocol (SNMP). It is therefore expected that NETCONF will
      provide all the capabilities that CLI and SNMP offer today and more.</t>

      <t>One of the operations that CLI offers today is the ability to issue
      an operation that might result in multiple responses being returned,
      till such time that a terminaing condition is encountered or when the
      operation is cancelled. An example of such an operation is when the ping
      or a traceroute command is issued. In the former case, the operation can
      continue sending responses back till it is cancelled, while in the
      latter case there is usually a terminating condition that stops the
      responses. NETCONF protocol as defined today sends a single Remote
      Procedure Call (RPC) request and expects a single reply to that request.
      The "persistent" operation defined above expects multiple responses for
      a single request, till such time a terminating condition is
      encountered.</t>

      <t>This problem should not be confused with "bulk responses" where one
      might be dealing with fragments of the same response. It is not enough
      to have the server collect all the possible responses before responding
      because in some cases there may not be a response, indicating a failure
      and it will hold up the NETCONF session till a response is received.</t>

      <t>Section 2 suggest at least one solution to this problem.</t>

      <t>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 <xref
      target="RFC2119">Key words for use in RFCs to Indicate Requirement
      Levels</xref>.</t>

      <section title="Terminology">
        <t/>

        <texttable>
          <ttcol>Acronym</ttcol>

          <ttcol>Meaning</ttcol>

          <c>CLI</c>

          <c>Command Line Interface</c>

          <c>RPC</c>

          <c>Remote Procedure Call</c>

          <c>SNMP</c>

          <c>Simple Network Management Protocol</c>
        </texttable>
      </section>
    </section>

    <section title="Solution">
      <t>The proper solution should address the requirement of multiple
      responses, fragmented responses and an ability to terminate the request
      without terminating the NETCONF session. This can be best achieved at
      the messaging layer in NETCONF, where a single request can result in
      multiple responses being received and way to associate the multiple
      responses with the original request.</t>

      <t>One of the suggested solutions would look like this. A request goes
      out with the operation to perform.</t>

      <t>&lt;rpc message-id="101" link-id="201" xmlns="..."&gt;</t>

      <t>&lt;/rpc&gt;</t>

      <t>And a reply can come back with either a &lt;rpc-reply&gt; as it
      happens today or a series of "linked replies" which would look like
      this.</t>

      <t>&lt;rpc-reply message-id="101" next-message-id="102" link-id="201"
      xmlns="..."&gt;</t>

      <t>&lt;/rpc-reply&gt;</t>

      <t>&lt;rpc-reply message-id="102" next-message-id="103" link-id="201"
      xmlns="..."&gt;</t>

      <t>&lt;/rpc-reply&gt;</t>

      <t>with the last reply looking like this.</t>

      <t>&lt;rpc-reply message-id="101" message-id="103" link-id="201"
      xmlns="..."&gt;</t>

      <t>&lt;/rpc-reply&gt;</t>

      <t>When the client wants to terminate the task, it issues an
      &lt;rpc-cancel&gt; to terminate the condition. Note, NETCONF currently
      does not support this particular operation.</t>

      <t>&lt;rpc-cancel link-id="201"&gt;</t>

      <t>&lt;/rpc-cancel&gt;</t>

      <t>And a reply comes back acknowledging that the task was
      terminated.</t>

      <t>&lt;rpc-reply&gt;</t>

      <t>&lt;ok/&gt;</t>

      <t>&lt;/rpc-reply&gt;</t>
    </section>

    <section anchor="IANA" title="IANA Considerations">
      <t/>
    </section>

    <section anchor="Security" title="Security Considerations"/>

    <section anchor="Acknowledgements" title="Acknowledgements">
      <t/>
    </section>
  </middle>

  <back>
    <references title="Normative References">
      <?rfc include='reference.RFC.2119'?>

      <?rfc include='reference.RFC.6241'?>
    </references>

    <references title="Informative References">
      <?rfc include='reference.RFC.6243'?>
    </references>
  </back>
</rfc>
