One document matched: draft-irtf-nmrg-an-gap-analysis-02.xml


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<rfc category="info" docName="draft-irtf-nmrg-an-gap-analysis-02"
     ipr="trust200902">
  <front>
    <title abbrev="Autonomic Networking Gap Analysis">Gap Analysis for
    Autonomic Networking</title>

    <author fullname="Sheng Jiang" initials="S." surname="Jiang">
      <organization>Huawei Technologies Co., Ltd</organization>

      <address>
        <postal>
          <street>Q14, Huawei Campus, No.156 Beiqing Road</street>

          <city>Hai-Dian District, Beijing, 100095</city>

          <country>P.R. China</country>
        </postal>

        <email>jiangsheng@huawei.com</email>
      </address>
    </author>

    <author fullname="Brian Carpenter" initials="B. E." surname="Carpenter">
      <organization abbrev="Univ. of Auckland"></organization>

      <address>
        <postal>
          <street>Department of Computer Science</street>

          <street>University of Auckland</street>

          <street>PB 92019</street>

          <city>Auckland</city>

          <code>1142</code>

          <country>New Zealand</country>
        </postal>

        <email>brian.e.carpenter@gmail.com</email>
      </address>
    </author>

    <author fullname="Michael H. Behringer" initials="M.H."
            surname="Behringer">
      <organization>Cisco Systems</organization>

      <address>
        <postal>
          <street>Building D, 45 Allee des Ormes</street>

          <city>Mougins 06250</city>

          <country>France</country>
        </postal>

        <email>mbehring@cisco.com</email>
      </address>
    </author>

    <date day="2" month="October" year="2014" />

    <area>IRTF</area>

    <workgroup>Network Management Research Group</workgroup>

    <abstract>
      <t>This document provides a problem statement and gap analysis for an IP-based
      autonomic network that is mainly based on distributed network devices.
      The document provides a background by reviewing the current status of autonomic aspects
      of IP networks and the extent to which current network management depends on 
      centralisation and human administrators. Finally the document describes the general
      gaps between current network abilities and the ideal autonomic network concept.</t>
    </abstract>
  </front>

  <middle>
    <section anchor="intro" title="Introduction">
      <t>The general goals and relevant definitions for autonomic networking
      are discussed in <xref
      target="I-D.irtf-nmrg-autonomic-network-definitions"></xref>. In
      summary, the fundamental goal of an autonomic network is
      self-management, including self-configuration, self-optimization,
      self-healing and self-protection. Whereas interior gateway routing
      protocols such as OSPF and IS-IS largely exhibit these properties, most
      other aspects of networking require top-down configuration, often
      involving human administrators and a considerable degree of
      centralisation. In essence Autonomic Networking is putting all network
      configurations onto the same footing as routing, limiting manual or
      database-driven configuration to an essential minimum. It should be
      noted that this is highly unlikely to eliminate the need for human
      administrators, because many of their essential tasks will remain. The
      idea is to eliminate tedious and error-prone tasks, for example manual
      calculations, cross-checking between two different configuration files,
      or tedious data entry. Higher level operational tasks, and complex
      trouble-shooting, will remain to be done by humans.</t>

      <t>This document first provides background by identifying examples of partial autonomic
      behavior in the Internet, and by describing important areas of non-autonomic
      behavior. Based on these observations, it then describes missing general mechanisms
      which would allow autonomic behaviours to be added throughout the Internet. </t>
   
    </section>

    <!-- intro -->

    <section anchor="terms" title="Terminology">
      <t>The terminology defined in <xref
      target="I-D.irtf-nmrg-autonomic-network-definitions"></xref> is used in
      this document. <!-- Additional terms include:</t>

      <t><list style="symbols">
          <t>Automatic: A process that occurs without human intervention, with
          step-by-step execution of rules. However it relies on humans
          defining the sequence of rules, so is not Autonomic in the full
          sense. For example, a start-up script is automatic but not
          autonomic.</t>
        </list> --> </t>
    </section>

    <!-- terms -->
    
    <section anchor="Background" title="Background">
    <section anchor="Status"
             title="Automatic and Autonomic Aspects of Current IP Networks">
      <t>This section discusses the history and current status of automatic
      or autonomic operations in
      various aspects of network configuration, in order to establish a
      baseline for the gap analysis.  In particular, routing
      protocols already contain elements of autonomic processes,
      such as information exchange and state synchronization.
      </t>

      <section title="IP Address Management and DNS">
        <t>Originally there was no alternative to completely manual and static
        management of IP addresses. Once a site had received an IPv4 address
        assignment (usually a Class C /24 or Class B /16, and rarely a Class A
        /8) it was a matter of paper-and-pencil design of the subnet plan (if
        relevant) and the addressing plan itself. Subnet prefixes were
        manually configured into routers, and /32 addresses were assigned
        administratively to individual host computers, and configured manually
        by system administrators. Records were typically kept in a plain text
        file or a simple spreadsheet.</t>

        <t>Clearly this method was clumsy and error-prone as soon as a site
        had more than a few tens of hosts, but it had to be used until DHCP
        <xref target="RFC2131"></xref> became a viable solution during the
        second half of the 1990s. DHCP made it possible to avoid manual
        configuration of individual hosts (except, in many deployments, for a
        small number of servers configured with static addresses).</t>

        <t>In terms of management, it is difficult to separate IP address
        management from DNS management. At roughly the same time as DHCP came
        into widespread use, it became very laborious to manually maintain DNS
        source files in step with IP address assignments. Because of reverse
        DNS lookup, it also became necessary to synthesise DNS names even for
        hosts that only played the role of clients. Therefore, it became
        necessary to synchronise DHCP server tables with forward and reverse
        DNS. For this reason, Internet Protocol address management tools
        emerged. These are, however, a centralised and far from autonomic type
        of solution.</t>

        <!-- <t>IPv6 has complicated the situation. Using DHCPv6 <xref
        target="RFC3315"></xref>, the situation is similar to IPv4. However,
        IPv6 also allows stateless address auto-configuration, which is
        largely autonomic, as long as the local router is correctly configured
        to provide Router Advertisements. There is significant disagreement in
        the community which of these methods is better, and there are
        coexistence issues.</t> -->

        <t>A related issue is prefix delegation, especially in IPv6 when more
        than one prefix may be delegated to the same physical subnet. DHCPv6
        Prefix Delegation <xref target="RFC3633"></xref> is a useful solution,
        but how this topic is to be handled in home networks is still an open
        question. Still further away is automated assignment and delegation of
        IPv4 subnet prefixes.</t>

        <t>Another complication is the possibility of Dynamic DNS Update <xref
        target="RFC2136"></xref>. With appropriate security, this is an
        autonomic approach, where no human intervention is required to create
        the DNS records for a host. Also, there are coexistence issues with a
        traditional DNS setup.</t>
      </section>

      <section title="Routing">
        <t>Since a very early stage, it has been a goal that Internet routing
        should be self-healing when there is a failure of some kind in the
        routing system (i.e. a link or a router goes wrong). Also, the problem
        of finding optimal routes through a network was identified many years
        ago as a problem in mathematical graph theory, for which well known
        algorithms were discovered (the Dijkstra and Bellman-Ford algorithms).
        Thus routing protocols became largely autonomic in the 1980s, as soon
        as the network was large enough for manual configuration of routing
        tables to become difficult.</t>

        <t>IGP routers do need some initial configuration data to start up the
        autonomic routing protocol. Also, BGP-4 routers need detailed static
        configuration of routing policy data. </t>
      </section>

      <section title="Configuration of Default Router in a Host">
        <t>Originally this was a manual operation. Since the deployment of
        DHCP, this has been automatic as far as most IPv4 hosts are
        concerned, but the DHCP server must be appropriately configured. In
        simple environments such as a home network, the DHCP server resides in
        the same box as the default router, so this configuration is also
        automatic. In more complex environments, where an independent DHCP
        server or a local DHCP relay is used, DHCP configuration is more complex
        and not automatic.</t>

        <t>In IPv6 networks, the default router is provided by Router
        Advertisement messages <xref target="RFC4861"></xref> from the router
        itself, and all IPv6 hosts make use of it. The router may also provide
        more complex Route Information Options. The process is essentially autonomic as
        far as all IPv6 hosts are concerned, and DHCPv6 is not involved.
        However, there are still open issues when more than one prefix is in
        use on a subnet and more than one first-hop router may be available as
        a result. </t>
      </section>

      <section title="Hostname Lookup">
        <t>Originally host names were looked up in a static table, often
        referred to as /etc/hosts from its traditional file path in Unix
        systems. When the DNS was deployed during the 1980s, all hosts needed
        DNS resolver code, and needed to be configured with the IP addresses
        (not the names) of suitable DNS servers. Like the default router,
        these were originally manually configured. Today, they are provided
        automatically via DHCP or DHCPv6 <xref target="RFC3315"></xref>. For
        IPv6 end systems, there is also a way for them to be provided
        automatically via a Router Advertisement option. However, the DHCP or
        DHCPv6 server, or the IPv6 router, need to be configured with the
        appropriate DNS server addresses.</t>
      </section>

      <section title="User Authentication and Accounting">
        <t>Originally, user authentication and accounting was mainly based on
        physical connectivity and the degree of trust that follows from
        direct connectivity. Network operators charged based on the
        set up of dedicated physical links with users. Automated user
        authentication was introduced by Point-to-Point Protocol <xref
        target="RFC1661"></xref>, <xref target="RFC1994"></xref> and RADIUS
        protocol <xref target="RFC2865"></xref>, <xref
        target="RFC2866"></xref> in early 1990s. As long as a user completes
        online authentication through the RADIUS protocol, the accounting for that
        user starts on the corresponding AAA server automatically. This mechanism enables
        business models with charging based on traffic
        based or time based usage. However, the management of user authentication
        information remains manual by network administrators. It also becomes
        complex in the case of mobile users who roam between operators, since
        prior relationships between the operators are needed. </t>
      </section>

      <section title="Security">
        <t>Security has many aspects that need configuration and are therefore
        candidates to become autonomic. On the other hand, it is essential
        that a network's central policy should be applied strictly for all
        security configurations. As a result security has largely been based
        on centrally imposed configurations.</t>

        <t>Many aspects of security depend on policy, for example firewall
        policies. Policies are by definition human made and will therefore
        also persist in an autonomic environment. However, policies are
        becoming more high-level, abstracting for example addressing, and
        focusing on the user or application. The methods to manage, distribute
        and apply policy, and to monitor compliance and violations could be
        autonomic.</t>

        <t>Today, many security mechanisms show some autonomic properties. For
        example user authentication via 802.1x allows automatic mapping of
        users after authentication into logical contexts (typically VLANs).
        While today configuration is still very important, the overall
        mechanism displays signs of self-adaption to changing situations.</t>

        <t>BGP Flowspec <xref target="RFC5575"></xref> allows a partially
        autonomic threat defense mechanism, where threats are identified, the
        flow information is automatically distributed, and counter-actions can
        be applied. Today typically a human operator is still in the loop to
        check correctness, but over time such mechanisms can become more
        autonomic.</t>

        <t>Negotiation capabilities, present in many security protocols, also
        display simple autonomic behaviours. In this case a security policy
        about algorithm strength can be configured into servers but will
        propagate automatically to clients. <!-- A proposal has been made recently
        for automatic bootstrapping of trust in a network <xref
        target="I-D.behringer-default-secure"></xref>.  Solutions for
        opportunistic encryption have been defined <xref
        target="RFC4322"></xref>, <xref
        target="I-D.farrelll-mpls-opportunistic-encrypt"></xref>, but these do
        not adhere to a central policy. --> </t>


      </section>

      <section title="Synchronization">

       <t>Another area where autonomic processes between peers are involved
       is state synchronization. In this case, several devices start out with
       inconsistent state and go through a peer-to-peer procedure after which their
       states are consistent. Network time synchronisation <xref target="RFC5905"/>
       is a well-established example, guaranteeing that a participating node's
       clock state is synchronized with reliable time servers within a defined
       margin of error, without any overall controller being involved. </t>

      </section>

      <section title="Miscellaneous">
        <t>There are innumerable other properties of network devices and end
        systems that today need to be configured either manually or using a
        management protocol such as SNMP <xref target="RFC1157"></xref> or
        NETCONF <xref target="RFC6241"></xref>. In a truly autonomic network,
        all of these, without exception, would need to either have satisfactory
        default values or be configured automatically. Some examples are
        parameters for tunnels of various kinds, flows (in an SDN context),
        quality of service, service function chaining, energy management,
        system identification and NTP configuration. </t>
      </section>
    </section> <!-- Status -->

    <!--
      <section anchor="summary" title="Summary of Autonomic Status and Trends">
      <t>The most advanced area is of course routing protocols, where we
      observe that a minimal amount of information must be pre-configured
      (neighbour routers, prefixes supported, and BGP-4 policies) and the rest
      is calculated dynamically as a result of peer-to-peer communication with
      other routers. In all other areas, there has been a slow progress over
      many years from fully manual configuration towards top-down
      configuration from central administrators or network management systems
      driven by databases. There are only a few instances, such as negotiation
      of cryptographic algorithms, where automation is not in the top-down
      style that relies ultimately on humans - either to correctly create and
      maintain configuration files, or to correctly use a network management
      system to do this work. At the moment the trend seems to be towards more
      widespread deployment of tools to help centralised configuration, such
      as IPAM tools, rather than to move away from this towards a more
      distributed and autonomic approach.</t>
    </section> -->

    <!-- summary-->

    <section anchor="NonAuto"
             title="Current Non-Autonomic Behaviors">
      <t>In current networks, many operations are still heavily dependent
      on human intelligence and decision, or on centralised top-down network
      management systems. These operations are the targets of Autonomic
      Network technologies. The ultimate goal of an Autonomic Network is to
      replace human and automated operations by autonomic
      functions, so that the networks can run independently without
      depending on a human or NMS system for routine details, while
      maintaining central control where required. Of course, there would 
      still be the absolute minimum of human input required, particularly 
      during the network establishment stage, and during emergencies and
      difficult trouble-shooting. </t>

      <t>This section analyzes the existing human and central dependencies in
      typical current networks and suggests cases where they could in principle
      be replaced by autonomic behaviors.</t>

      <section title="Network Establishment">
        <t>Network establishment requires network operators to analyze the
        requirements of the new network, design a network architecture and
        topology, decide device locations and capacities, set up hardware,
        design network services, choose and enable required protocols,
        configure each device and each protocol, set up central user authentication
        and accounting policies and databases, design and deploy security
        mechanisms, etc.</t>

        <t>Overall, these jobs are quite complex work that cannot become fully
        autonomic in the foreseeable future. However, part of these jobs may be
        able to become autonomic, such as detailed device and protocol
        configurations and database population. The initial network management
        policies/behaviors may also be transplanted from other networks and
        automatically localized.</t>
      </section>

      <section title="Network Maintenance and Management">
        <t>Network maintenance and management are very different for ISP
        networks and enterprise networks. ISP networks have to change much
        more frequently than enterprise networks, given the fact that ISP
        networks have to serve a large number of customers who have very
        diversified requirements. The current rigid model is that network
        administrators design a limited number of services for customers to
        order. New requirements of network services may not be able to be met
        quickly by human management. Given a real-time request, the response
        must be autonomic, in order to be flexible and quickly deployed.
        However, behind the interface, describing abstracted network
        information and user authorization management may have to depend on
        human intelligence from network administrators in the foreseeable
        future. User identification integration/consolidation among networks
        or network services is another challenge for autonomic network access.
        Currently, many end users have to manually manage their user accounts
        and authentication information when they switch among networks or
        network services.</t>

        <t>Classical network maintenance and management mainly manages the
        configuration of network devices. Tools have been developed to enable
        remote management and make such management easier. However, the
        decision about each configuration detail depends either on human
        intelligence or rigid templates. This is the source of most network
        configuration errors. It is also a barrier to increasing the utility of network
        resources, because the human managers cannot respond quickly enough
        to network events, such as traffic bursts, etc. For example,
        currently, a light load is normally assumed in network design because
        there is no mechanism to properly handle a sudden traffic flood. It is
        actually normal to avoid network crashes caused by traffic overload by
        wasting a huge amount of resources.</t>

        <t>It is worth noting that the introduction of new, more flexible,
        methods of network configuratiom, typified by software-defined networking
        (SDN), will only make this problem worse unless the details are managed
        autonomically. </t>

        <t>Autonomic decision processes for configuration would enable dynamic
        management of network resources (by managing resource-relevant
        configuration). Self-adapting network configuration would adjust the
        network into the best possible situation, which also prevents
        configuration errors from having lasting impact.</t>


      </section>

      <section title="Security Setup">
        <t>Setting up security for a network generally requires very detailed
        human intervention, or relies entirely on default configurations that
        may be too strict or too risky for the particular situation of the
        network. While some aspects of security are intrinsically top-down
        in nature (e.g. broadcasting a specific security policy to all
        hosts), others could be self-managed within the network.  </t>
        <t>
        In an autonomic network, where nodes within a domain have a mutually
        verifiable domain identity, security processes could run entirely
        automatically. Nodes could identify each other securely, negotiating
        required security settings and even shared keys if needed. The location 
        of trust anchors (certificate authority, registration authority),  
        certificate revocation lists, policy server, etc., can be 
        found by service discovery. Transactions such as a certificate revocation 
        list download can be authenticated via a common trust anchor.  
        Policy distribution can also be entirely automated, and secured via 
        a common trust anchor. </t>
        
        <t>These concepts lead to a network where the intrinsic security is 
        automatic and applied by default, i.e., a "self-protecting" network. 
        For further discussion, see <xref target="I-D.behringer-default-secure"/>
        </t>
      </section>

   

      <section title="Troubleshooting and Recovery">
        <t>Current networks suffer difficulties in locating the cause of
        network failures. Although network devices may issue many warnings
        while running, most of them are not sufficiently precise to be
        identified as errors. Some of them are early warnings that would not
        develop into real errors. Others are in effect random noise. During a
        major failure, many different devices will issue multiple warnings
        within a short time, causing overload for the NMS and the operators.
        However, for many scenarios, human experience is still vital to
        identify real issues and locate them. This situation may be improved
        by automatically associating warnings from multiple network devices
        together. Also, introducing automated learning techniques (comparing
        current warnings with historical relationships between warnings and
        actual faults) could increase the possibility and success rate of
        autonomic network diagnoses and troubleshooting.</t>

        <t>Depending on the network errors, some of them may always require
        human interventions, particularly for hardware failures. However,
        autonomic network management behavior may help to reduce the impact of
        errors, for example by switching traffic flows around. Today this is
        usually manual (except for classical routing updates). Fixing software
        failures and configuration errors currently depends on humans, and may
        even involve rolling back software versions and rebooting hardware.
        Such problems could be autonomically corrected if there were
        diagnostics and recovery functions defined in advance for them. This
        would fulfill the concept of self-healing.</t>

        <t>Another possible autonomic function is predicting device failures
        or overloads before they occur. A device could predict its own failure
        and warn its neighbors; or a device could predict its neighbor's
        failure. In either case, an autonomic network could respond as if the
        failure had already occurred by routing around the problem and
        reporting the failure, with no disturbance to users. The criteria for
        predicting failure could be temperature, battery status, bit error
        rates, etc. The criteria for predicting overload could be increasing
        load factor, latency, jitter, congestion loss, etc.</t>
      </section>
    </section> <!-- NonAuto -->
    </section> <!-- Background -->

    <section anchor="Gaps" title="Features Needed by Autonomic Networks">
      <t>The task of autonomic networking is to build up individual autonomic
      processes that could properly combine to respond to every type of
      network event. Building on the preceding background information, and on the
      reference model in <xref target="I-D.irtf-nmrg-autonomic-network-definitions"/>,
      this section will outline the gaps and missing features in general terms,
      and in some cases mentions general design principles that should apply. </t>

      <section title="More Coordination among Devices or Network Partitions">

        <t>Network services are dependent on a number of devices and
        parameters to be in place in a certain order. For example
        after a power failure a coordinated sequence of "return to
        normal" operations is desirable (e.g., switches and routers
        first, DNS servers second, etc.). Today, the correct sequence
        of events is either known only by a human administrator, or
        automated in a central script. In a truly autonomic network,
        elements should understand their dependencies, and be able to
        resolve them locally. </t>

        <t>In order to make right or good decisions autonomically, the network
        devices need to know more information than just reachability (routing)
        information from the relevant or neighbor devices. There are
        dependencies between such information and configurations, which devices
        must be able to derive for themselves. </t>

        <t>There are therefore increased requirements for horizontal
        information exchange in the networks. Particularly, three types of
        interaction among peer network devices are needed for autonomic decisions:
        discovery (to find neighbours and peers), synchronization (to agree
        on network status) and negotiation (when things need to be changed).
        <!-- <xref target="I-D.jiang-config-negotiation-ps"></xref> analyzes such
        requirements. -->
        Although there are many existing protocols with some discovery, syncronization
        or negotiation ability, each of them only serves a specific and narrow purpose. 
        <!-- <xref target="I-D.jiang-config-negotiation-protocol"></xref>
        is one of the attempts to create -->
        To avoid continued proliferation of such protocols,
        there is a need for reusable discovery, synchronization and negotiation mechanisms, which
        would support the discovery of many different types of device, the synchronization of
        many types of parameter and the negotiation of many different types of objective. </t>
      </section>

      <section title="Reusable Common Components">
        <t>Elements of autonomic functions already exist today, within many
        different protocols. However, all such functions have their own
        discovery, transport, messaging and security mechanisms as well as
        non-autonomic management interfaces. Each protocol has its own version
        of the above-mentioned functions to serve specific and narrow
        purposes. It is often difficult to extend an existing protocol to
        serve different purposes. Therefore, in order to provide the
        reusable discovery, synchronization and negotiation mechanism mentioned above, it is
        desirable to develop a set of reusable common protocol components
        for Autonomic Networks. These components should be:
            <list style="symbols">

            <t>Able to identify other devices, users and processes securely.</t>

            <t>Able to automatically secure operations, based on the
            above identity scheme.</t>

            <t>Able to manage any type of information and information
            flows.</t>

            <t>Able to discover peer devices and services for various autonomic service
            agents (or autonomic functions).</t>

            <t>Able to support closed-loop operations when needed to provide
            self-managing functions involving more than one device.</t>

            <t>Separable from the specific autonomic
            service agents (or autonomic functions).</t>

            <t>Reusable by other autonomic functions.</t>
          </list></t>
      </section>

      <section title="Secure Control Plane">
      <t>The common components will in effect act as a control plane for autonomic
      operations, regardless whether they are implemented in-band as functions of
      the target network, in an overlay network, or even out-of-band in a separate
      network. Autonomic operations will be capable of changing how the network
      operates and allocating resources without human intervention or knowledge,
      so it is essential that they are secure. Therefore the control plane must be
      fully secure against forged autonomic operations and man-in-the middle attacks,
      and as secure as reasonably possible against denial of service attacks.
      It must be decided whether the control plane needs to be resistant to unwanted
      monitoring, i.e., whether encryption is required. </t>
      </section>

      <section title="Less Configuration">
        <t>Most existing protocols have been defined to be as flexible as
        possible. Consequently, these protocols need many initial
        configurations to start operations. There are many choices and options
        that are unnecessary in any particular case. A large portion of these
        configurations target corner cases. Furthermore, in many protocols
        that already exist for years, some design considerations are no longer
        valid since the hardware technologies have made dramatic progress in
        recent years. There is much scope for simplifying the protocols and
        the operation of protocols.</t>

        <t>From another perspective, the deep reason why human decisions are
        often needed mainly result from the lack of information. When a device
        can collect enough information horizontally from other devices, it
        should be able to decide many parameters by itself, instead of
        receiving them from top-down configuration.</t>

        <t>It is desired that the top-down management is reduced in the
        Autonomic Networking. Ideally, only the abstract intent is needed from
        the human administrators. Neither users nor administrators should need
        to create and maintain detailed policies and profiles; if they are needed, they
        should be built autonomically. The local parameters should be decided by
        distributed Autonomic Nodes themselves, either from historic
        knowledge, analytics of current conditions, closed logical decision
        loops, or a combination of all.</t>
      </section>

      <section title="Forecasting and Dry Runs">
        <t>In a conventional network, there is no mechanism for trying
        something out. That means that configuration changes have to be
        designed in the abstract and their probable effects have to be
        estimated theoretically. The only alternative to this would be to test
        them on a complete and realistic network simulator, which is unlikely
        to be possible for a network of any size. In any case, there is a risk
        that applying the changes to the running network will cause a failure
        of some kind. An autonomic network should fill this gap by supporting a
        "dry run" mode in which a configuration change could be tested out in
        the control plane without actually affecting the data plane. If the
        results are satisfactory, the change could be made live; if there is a
        problem, the change could be rolled back with no impact on users.</t>
      </section>

      <section title="Benefit from Knowledge">
        <t>The more knowledge we have, the more intelligent we are. It is the
        same for networks and network management. It is when one component in
        the network lacks knowledge that affects what it should do, and
        another component has that knowledge, that we usually rely on a human
        operator or a centralised management tool to convey the knowledge.</t>

        <t>Up to now, the only available network knowledge is usually the current
        network status inside a given device or relevant current status from other
        devices.</t>

        <t>However, historic knowledge is very helpful to make correct
        decisions, in particular to reduce network oscillation or to manage
        network resources over time. Transplantable knowledge from other
        networks can be helpful to initially set up a new network or new
        network devices. Knowledge of relationships between network events and
        network configuration may help a network to decide the best parameters
        according to real performance feedback.</t>

        <t>In addition to such historic knowledge, powerful data analytics of
        current network conditions may also be a valuable source of knowledge
        that can be exploited directly by autonomic nodes.</t>
      </section>
    </section>

    <!-- gaps -->

    <section anchor="security" title="Security Considerations">
      <t>This document is focused on what is missing to allow autonomic
      network configuration, including of course security settings. Therefore,
      it does not itself create any new security issues. It is worth
      underlining that autonomic technology must be designed with strong
      security properties from the start, since a network with vulnerable
      autonomic functions would be at great risk. </t>
    </section>

    <section anchor="IANA" title="IANA Considerations">
      <t>This memo includes no request to IANA.</t>
    </section>

    <section anchor="ack" title="Acknowledgements">
      <t>The authors would like to acknowledge the valuable comments made by
      participants in the IRTF Network Management Research Group. A review by
      Rene Struik was especially helpful. </t>

      <t>This document was produced using the xml2rfc tool <xref
      target="RFC2629"></xref>.</t>
    </section>

    <section anchor="changes" title="Change log [RFC Editor: Please remove]">


      <t>draft-irtf-nmrg-an-gap-analysis-02: Review comments actioned, 2014-10-02.</t>

      <t>draft-irtf-nmrg-an-gap-analysis-01: RG comments added and more
      content in "Approach toward Autonomy" section, 2014-08-30.</t>

      <t>draft-irtf-nmrg-an-gap-analysis-00: RG comments added,
      2014-04-02.</t>

      <t>draft-jiang-nmrg-an-gap-analysis-00: original version,
      2014-02-14.</t>
    </section>

    <!-- changes -->
  </middle>

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      <?rfc include='reference.RFC.1157'?>

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      <?rfc include='reference.RFC.1994'?>

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      <?rfc include='reference.RFC.2865'?>

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      <?rfc include='reference.RFC.3315'?>

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