Requirements for Automated (Configuration) Management

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Authors Mohamed Boucadair  , Christian Jacquenet  , Luis Contreras 
Last updated 2014-02-14
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Network Working Group                                       M. Boucadair
Internet-Draft                                              C. Jacquenet
Intended status: Informational                            France Telecom
Expires: August 18, 2014                                    L. Contreras
                                                          Telefonica I+D
                                                       February 14, 2014

         Requirements for Automated (Configuration) Management


   Given the ever-increasing complexity of the configuration tasks
   required for the dynamic provisioning of IP networks and services,
   this document aims at listing the requirements for an automated
   configuration management framework.

Status of This Memo

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   This Internet-Draft will expire on August 18, 2014.

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Motivation  . . . . . . . . . . . . . . . . . . . . . . . . .   5
   5.  Requirements Language . . . . . . . . . . . . . . . . . . . .   5
   6.  Issues Raised by Configuration Operations . . . . . . . . . .   5
     6.1.  Heterogeneous Environments  . . . . . . . . . . . . . . .   6
     6.2.  Complex Topologies  . . . . . . . . . . . . . . . . . . .   6
     6.3.  Multi-Functional Devices  . . . . . . . . . . . . . . . .   6
     6.4.  Performance Impacts . . . . . . . . . . . . . . . . . . .   7
     6.5.  Scalability . . . . . . . . . . . . . . . . . . . . . . .   7
     6.6.  Limits of Manual Configuration  . . . . . . . . . . . . .   8
     6.7.  Security Issues . . . . . . . . . . . . . . . . . . . . .   8
   7.  Introducing Service-Driven Configuration Management . . . . .   8
   8.  Requirements  . . . . . . . . . . . . . . . . . . . . . . . .   9
     8.1.  Protocol Requirements . . . . . . . . . . . . . . . . . .   9
       8.1.1.  Functional Requirements . . . . . . . . . . . . . . .  10
       8.1.2.  Performance Requirements  . . . . . . . . . . . . . .  11
       8.1.3.  Backward Compatibility  . . . . . . . . . . . . . . .  11
     8.2.  Requirements for Configuration Information  . . . . . . .  11
       8.2.1.  Network Services  . . . . . . . . . . . . . . . . . .  12
       8.2.2.  Forwarding Services . . . . . . . . . . . . . . . . .  13
     8.3.  Global Management Requirements  . . . . . . . . . . . . .  15
       8.3.1.  Fault Management  . . . . . . . . . . . . . . . . . .  15
       8.3.2.  Configuration Management  . . . . . . . . . . . . . .  15
       8.3.3.  Performance Management  . . . . . . . . . . . . . . .  15
     8.4.  Security Management . . . . . . . . . . . . . . . . . . .  16
       8.4.1.  Device Authentication . . . . . . . . . . . . . . . .  16
       8.4.2.  Integrity of Configuration Information  . . . . . . .  16
       8.4.3.  Confidentiality of Exchanged Data . . . . . . . . . .  16
       8.4.4.  Key Management  . . . . . . . . . . . . . . . . . . .  16
       8.4.5.  Connection Log  . . . . . . . . . . . . . . . . . . .  16
       8.4.6.  Profiles  . . . . . . . . . . . . . . . . . . . . . .  17
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  17
   10. Security Considerations . . . . . . . . . . . . . . . . . . .  17
   11. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  17
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . .  17
     12.1.  Normative References . . . . . . . . . . . . . . . . . .  17
     12.2.  Informative References . . . . . . . . . . . . . . . . .  18
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  19

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1.  Introduction

   IP network and service configuration procedures are currently handled
   by skilled personnel who is often required to acquire a high level of
   expertise that grows as the variety and the complexity of the
   services to be delivered over an IP network.  This demand for a high
   level of expertise is further increased by heterogeneous network and
   service environments where each equipment manufacturer has developed
   its own proprietary interfaces and configuration schemes.  As a
   consequence, the time to deliver complex yet advanced IP service
   offerings (such as IPTV, VPN, etc.) is also increasing at the risk of
   jeopardizing customers' quality of experience.

   This document advocates for the need to undertake a standardization
   effort to define an automated provisioning framework that includes a
   set of interfaces and protocol(s) for conveying configuration
   information which should help in facilitating the automation of the
   network resource allocation and service delivery procedures.
   Defining standard data and information models [RFC3444] to capture
   offered network services would help to automate the process of
   service ordering and activation and therefore accelerating service

   Automation should not be targeted at dynamically enforcing policies
   only, but also be encouraged to:

   o  Generate policy-related and configuration data based on a well-
      defined set of triggers and events.
   o  Monitor the outcome of a configured function/device to assess
      whether the observed behavior is aligned with the expected

   This document assumes that service differentiation at the network
   layer can be enforced by tweaking various parameters which belong to
   distinct dimensions (e.g, forwarding, routing, traffic access
   management, traffic classification, etc.).  As such, the decision
   point is likely to interact with several engines (e.g., routing
   engine, forwarding engine, etc.).  In particular, this document
   considers that an I2RS system can be seen as a subset of an overall
   framework.  I2RS is limited to routing and forwarding actions (see
   Section 8.2.2).  To meet performance requirements (see
   Section 8.1.2), it is encouraged to design a system which interacts
   directly with the routing and forwarding system, rather than
   requiring local proxy functions which are responsible for translating
   vendor-independent commands and policies into vendor-specific
   configuration commands and syntax.

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   In addition to protocol-related considerations, automating network
   operations heavily relies upon the availability of intelligent policy
   decision points.  Sharing best design practices for policy decision
   point logics would facilitate the adoption of the proposed approach
   (see Section 7).

   The document enumerates a set of encountered issues (see Section 6)
   and identifies a set of requirements (see Section 8).  A service-
   driven approach is purposed in Section 7.

2.  Terminology

   This document makes use of the following terms:

   o  Decision point: is an entity that is responsible for making
      decisions that yield the production of configuration information
      which will be conveyed towards (and processed by) the set of
      relevant managed entities.
   o  Managed entity: any (networking) device that will participate in
      the establishment, the activation and the maintenance of a given
      service.  Such devices MAY include routers and terminals, whatever
      the configuration procedures and underlying technologies to be
      used for the delivery of the said service.

3.  Scope

   Maintain and operate self-adaptive networks may be seen as a long
   term objective for IP service providers.  To achieve this goal,
   intermediate objectives should be defined, such as:

   1.  Define a framework to expose IP connectivity services to external
       parties, including peering IP network operators, content
       providers, services relying on connectivity services (e.g., IP
       TV, VoIP) (see for example
   2.  Ability to automatically translate IP connectivity requirements
       into configuration and provision actions.
   3.  Dynamically adapt service configuration to be aligned with
       expected service objectives.
   4.  Automate service negotiation and service activation (e.g.,
   5.  Optimize resource utilization, e.g., automatically set traffic
       engineering objectives.

   Discussing the items above is out of scope.  This document only
   discusses requirements for (automated) configuration procedures and

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4.  Motivation

   Service providers and network operators have gained experience in
   implementing, deploying and manipulating a large set of protocols and
   associated information.  Some data models have also been defined for
   network management purposes.  Thus, several protocols have been
   standardized, such as SNMP (Simple Network Management Protocol
   [RFC3410]), COPS (Common Open Policy Service [RFC2748]), (COPS-PR
   [RFC3084]) or, more recently, NETCONF [RFC6241].

   In addition, multiple data models have been defined and used by
   operators like CIM (Core Information Model), DEN (Directory-Enabled
   Network), SMI (Structure of Management Information [RFC2578]), SPPI
   (Structure of Policy Provisioning Information [RFC3159]), and, more
   recently, YANG [RFC6022].

   Despite this standardization effort, most of the service operators
   still assume manual configuration through proprietary CLI (Command
   Line Interface) commands possibly combined with in-house developed,
   vendor-specific scripts to proceed with the configuration of numerous
   features, such as forwarding and routing capabilities, Quality of
   Service (sometimes including traffic engineering) capabilities, and
   security capabilities.  Some of these requirements are fulfilled by
   existing tools/protocols but there is still a lack of wide adoption
   of those tools.

   Other non-technological challenges are also to be taken into
   consideration when discussing network automation (e.g., to what
   extent an automated system will accommodate both simple and complex
   business scenarios, how an automated system will evolve to
   accommodate changes and new procedures, assess the impact on testing

   The purpose of this document is to document requirements rather than
   focusing on the non-technological challenges.

5.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in [RFC2119].

6.  Issues Raised by Configuration Operations

   The following sub-sections enumerates a set of issues.

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6.1.  Heterogeneous Environments

   The delivery of IP services relies upon the activation of a set of
   capabilities located in various devices that include routers,
   switches, service platforms, etc.  In particular, a large set of
   protocols need to be configured, such as routing protocols,
   management protocols, security protocols, let alone capabilities that
   relate to addressing scheme management, policy enforcement, etc.

   Such a diversity of features and protocols may increase the risk of
   inconsistency at the cost of QoS degradation or even service
   disruption.  Therefore, the configuration information which is
   forwarded to the whole set of participating devices for delivering a
   given service or a set of services should be consistent, whatever the
   number of features/services to be activated/deployed in the network.

6.2.  Complex Topologies

   Network operators should have means to dynamically discover the
   topology of their network.

   Such topological information should be as elaborate as possible,
   including details like the links that connect network devices, their
   capacity, such as the total bandwidth, the available bandwidth, the
   bandwidth that can be reserved, etc.

6.3.  Multi-Functional Devices

   Numerous, often multi-vendor devices are involved in the delivery of
   IP services.  These devices support various capabilities that need to
   be combined for the delivery of a given service or a set of services.
   The availability and status of such capabilities is therefore a
   critical information for service providers, since it is likely to
   affect service and network design, let alone operational procedures.

   Therefore, service providers and network operators should have means

   o  Dynamically retrieve, list and classify the capabilities supported
      by a given device (or a set thereof),
   o  Dynamically acquire detailed information about the availability
      and status of any activated capability of any device at any given
   o  Dynamically retrieve the version of embedded software modules,
      interfaces, OS version, etc.

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6.4.  Performance Impacts

   Configuring a set of devices to deliver a service takes time.  In
   addition, depending on the complexity of the service, erroneous
   configurations may occur at the cost of jeopardizing the overall
   quality of a service, if not causing service disruption.  From this
   perspective, some performance indicators must be defined and measured
   to assess:

   o  The time to deliver a service, from subscription to operation.
      Such indicator may be further decomposed into elementary
      performance metrics, e.g., the time it takes to complete the
      configurations tasks that are specific to the enforcement of a
      given policy (forwarding, routing, QoS, etc.)
   o  The impact of any configuration change on the overall service
      performance (including customer's own perception).

   Tools to qualify (by simulation or emulation) any possible impact of
   an elementary configuration task before such task is performed should
   be supported.  These tools aims to prevent errors amplification.

6.5.  Scalability

   As far as scalability is concerned, adequate indicators should be
   specified in order to assess the ability of configuration techniques
   and protocols to support a large number of simultaneous processes.
   The maintenance of these processes should not impact the performance
   of the configuration system as a whole (i.e., manager and managed
   entities, amount of configuration task-specific traffic exchanged
   between manager and managed entities, periodicity of configuration
   operations, etc.).

   Therefore, configuration operations should be qualified with
   performance indicators in order to check whether the architecture
   designed for configuration management is scalable in terms of:

   o  Amount of configuration data to be processed per unit of time, as
      a function of the number and the nature of the capabilities and
      devices that need to be configured.
   o  Amount of traffic generated by any reporting mechanism that may be
      associated to a configuration process.
   o  Number of processes that are created in order to achieve specific
      configuration operations.

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6.6.  Limits of Manual Configuration

   Manual configuration is not only a likely source of errors, but it
   also affects the time it takes to complete a configuration task (or a
   combination thereof) to deliver a service, as a function of the task
   complexity and the need for global consistency.  Thus, the efficiency
   of a configuration process is likely to be improved by the
   introduction of a high level of automation.  Automation is defined as

   o  Automatic provisioning of configuration information to the
      participating devices.
   o  Dynamic enforcement of policies (possibly based upon the use of
      dynamic resource allocation techniques).
   o  Dynamic reporting mechanisms to notify about the actual processing
      of configuration information by a participating device.
   o  Autonomic provisioning capabilities for triggering self-
      configuration mechanisms for the network devices.

   Refer to Section 4.1 of [I-D.sin-sdnrg-sdn-approach] for a discussion
   on the implications of full automation.

6.7.  Security Issues

   Configuring a network or a service raises several security issues,
   including (but not limited to):

   o  The integrity of the configuration information, possibly yielding
      the preservation of the confidentiality of such information when
      being forwarded over a public IP infrastructure,
   o  The need for authorizing and authenticating devices/entities that
      have the ability of manipulating configuration information
      (define, instantiate, forward and process),
   o  Mutual authentication between manager and managed entities.

7.  Introducing Service-Driven Configuration Management

   Current practice consists in configuring elementary functions, i.e.,
   configuration management for a given service offering is decomposed
   into a set of elementary tasks.  Thus, the consistency of
   configuration operations for the sake of service delivery must be
   checked by any means appropriate.

   A network device should be seen as a means to deploy a service and
   not just as a component of such service.  Thus, service delivery
   procedures should not assume the configuration of devices one after
   the other, but rather globally, i.e., at the scale of the network
   that supports the said service.  Such a service-driven configuration

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   management scheme is therefore meant to facilitate and improve the
   completion of configuration tasks, by means of highly automated,
   service-wise, global configuration procedures.

   This in particular assumes the need for robust configuration
   mechanisms that include appropriate protocol machinery (e.g., from a
   reliable transport mode perspective) to convey configuration
   information between manager and managed entities, as well as reliable
   consistency check procedures.  The latter is not only meant to assess
   the validity of all the configuration operations service-wise, but
   also the efficiency of the corresponding yet dynamic policy
   enforcement and resource allocation schemes.

   An implementation example is the case of service providers who could
   dedicate (logical) centralized entities which are responsible for the
   provisioning and the management of participating devices.  The main
   function of these centralized entities is to make appropriate
   decisions and generate the decision-derived configuration data that
   will be forwarded to the participating devices.  In addition, these
   centralized entities will make sure of the consistency of the
   decisions that have been made to deliver the service, according to a
   dynamic configuration policy enforcement scheme.  These logical
   entities will be responsible for assessing whether the enforced
   policies are compliant with the expected behavior and how efficiently
   they are enforced.

   Service-driven configuration management leads to the following

   o  Data and information models MUST be service-oriented,
   o  Configuration protocol(s) SHOULD reuse existing standard data and
      information models as much as possible,
   o  Configuration protocol(s) SHOULD be flexible enough to facilitate
      the support of new features without compromising the protocol
      robustness (especially from a performance and scalability
   o  Configuration protocol(s) SHOULD provide means to check the
      consistency of configuration information service-wise.

8.  Requirements

8.1.  Protocol Requirements

   Configuration information MUST be provided to the participating
   devices by means of a protocol to be used between such devices and a
   presumably centralized manager entity.  The latter can be seen as a
   decision point where configuration information is stored, maintained
   and updated whenever required.

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   Decisions about configuring additional features or devices, enforcing
   policies and allocating resources are made accordingly, e.g., as a
   function of the number of Service Level Specification templates that
   are processed per unit of time combined with traffic forecasts that
   are updated on a regular basis.  Such decisions are converted into
   configuration information that is forwarded towards the relevant
   managed entities.

8.1.1.  Functional Requirements

   The vendor-independent communication protocol for conveying
   configuration information SHOULD have the following characteristics:

   1.  The protocol MUST use a reliable transport mode, and be
       independent from the network layer (i.e., configuration
       information MUST be conveyed over IPv4 and IPv6 network
       infrastructures indifferently),
   2.  The protocol architecture SHOULD provide a means for dynamically
       providing the configuration information to the participating
       devices, so that a high level of automation is introduced in the
       actual delivery of any given service.
   3.  The protocol SHOULD provide the relevant means (encoding
       capabilities, operation and command primitives, extension
       capabilities that allow additional operations, etc.) to be able
       to reliably and securely convey configuration information,
   4.  The protocol SHOULD be a privileged vector for the dynamic
       provisioning of configuration data, as well as the dynamic
       enforcement of any policy such as a routing policy, a QoS policy
       or a security policy.  This requirement suggests the definition
       and the support of vendor-independent instantiation procedures
       that will aim at uniquely identifying the configuration data
       model and the policy enforcement scheme that refer to a given IP
   5.  The protocol SHOULD support a reporting mechanism for various
       purposes, including the assessment of the efficiency of a given
       policy, the ability to dynamically notify the aforementioned
       decision point about the completion of a set of configuration
       tasks, or the ability to dynamically report any event that may
       affect global service operation,
   6.  The protocol SHOULD support the appropriate security mechanisms
       to provide guarantees as far as the preservation of the
       confidentiality of the configuration information is concerned.
   7.  The protocol SHOULD provide a mean of preserving the order in
       which the configuration information should be applied in the
       participating devices.  The ordering of the configuration
       information could be implemented by means of sequence numbers,
       timing or scheduling indicators, etc.  Through this requirement,

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       any aged or disordered configuration information is prevented to
       be applied to the devices.

8.1.2.  Performance Requirements

   The protocol for conveying configuration information within a network
   should be designed so that:

   1.  The activation of the protocol by the participating devices MUST
       NOT affect the overall performance of such devices, whatever the
       amount of configuration data these devices will have to process
       at any given time.
   2.  The activation of the protocol SHOULD NOT dramatically affect the
       global resources of the network infrastructure that will convey
       configuration information whatever its amount and scope (e.g.,
       the set of policies that need to be dynamically enforced).

8.1.3.  Backward Compatibility

   The introduction and the activation of a protocol for conveying
   configuration information SHOULD allow for smooth migration
   procedures, so that vendor-specific and vendor-independent
   configuration procedures may gracefully co-exist on a (hopefully)
   limited period of time.

   Also, in case of any kind of protocol failure, it MUST be possible to
   rely upon any vendor-specific configuration procedure as some kind of
   rollback procedure.  Such a rollback procedure MUST protect services
   that are up and running from any risk of disruption.

8.2.  Requirements for Configuration Information

   Configuration tasks are currently performed with vendor-specific
   solutions that reflect technology-specific information.  It is
   therefore more and more difficult for a service provider to get a
   unified, homogeneous view of the network resources service-wise
   (rather than device-wise).

   Configuration information SHOULD therefore be provided to the
   participating devices as unified, vendor-agnostic, service
   configuration parameters.  These parameters MUST reflect a
   standardized service data model rather than a vendor-specific
   information model, unlike the current situation.  Examples of such
   service data models include a tunneling service, an intra-domain
   routing service, or a VPN service.

   The need for a unified, homogeneous access to a multi-vendor
   environment is becoming critical for N-Play, residential and

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   corporate, fixed and mobile service providers so that a high level of
   automation can be introduced while proceeding with the configuration
   of the said multi-vendor environment.  This unification is clearly
   conditioned by the availability of two key components: A
   configuration protocol (the container) and a set of data models (the

   The standardization of these two components has several yet major

   o  Devices are seen as functional blocks that support a set of
      standardized capabilities;
   o  These functional blocks are described as vendor-independent
   o  These functional blocks are all managed homogeneously, whatever
      the underlying technology.

   As a consequence, it becomes possible to add semantic rules to
   automate detection and correction of erroneous configurations, either
   at the scale of a single device or at the scale of a whole network.
   Furthermore, an equipment from vendor X could de replaced by another
   technology from vendor Y with very little impact (if no impact at
   all) on the configuration management procedures.

   To do so, the data models SHOULD satisfy the following requirements.

8.2.1.  Network Services  Interface Identification

   Configuration information for identification purposes mostly deals
   with the naming of any interface supported by a given device.  This
   naming scheme describes the properties of an interface, and must take
   into account all the parameters that are required to correctly
   configure an interface.  The following information MUST be provided:

   o  A name, with a generic syntax that is vendor-agnostic by nature.
      The name can define the media type of the interface.  Depending on
      the medium type, further information MAY be added (such as MTU,
      bandwidth, supported framing and encapsulation modes, etc.).
   o  The interface technology (e.g., optical / electrical) and nominal
      capacity (e.g., 10 GE / 100 GE).
   o  Optionally, a logical descriptor (e.g., VLANs declared on Ethernet
      interfaces).  In this case the encapsulation mode MUST be part of
      the configuration information.
   o  Optionally, a description field that provides general (possibly
      administrative) information about the interface.

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   IP services are provided with a level of quality that MAY be
   guaranteed (either qualitatively or quantitatively) by any means
   appropriate.  QoS policies SHOULD be dynamically enforced according
   to a data model that will accurately reflect all the elementary QoS
   capabilities that MAY be configured and activated to enforce such

   For instance, in the case of the activation of the DiffServ QoS model
   within a network infrastructure, the participating routers SHOULD be
   provided with the appropriate PHB (Per Hop Behavior) configuration

   Additional information relevant to the service, such as path
   protection, can be provided to the participating devices to mitigate
   network failures.  This information can be proactively or reactively
   provided, according to the service level agreed.  Applications

   Network devices usually support functions that allow the activation
   of specific services like HTTP, BOOTP, DHCP, SYSLOG, etc.  These
   devices MUST therefore be provided with the corresponding
   configuration information.

8.2.2.  Forwarding Services  Routing and Forwarding Configuration Information

   Routing and forwarding configuration information deals with the
   decision that should be applied by a participating device to forward
   an incoming IP datagram, according to the (possibly service-specific)
   forwarding and routing policies defined by the service provider.
   From this perspective, the participating devices should be provided
   with the following configuration information:

   1.  Metric information for IGP route computation purposes,
   2.  Attribute information for BGP route computation purposes,
   3.  Static routes (if any).

   Any candidate protocol MUST be compliant with the following

   1.  Ability to retrieve routing and forwarding tables.
   2.  Ability to retrieve the configuration information of each routing
       /forwarding device.

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   3.  Ability to retrieve the capabilities of each routing/forwarding
   4.  Ability to dynamically enforce policies on active routing
   5.  Ability to dynamically inject new routing and forwarding entries.
   6.  Ability to receive notifications when route changes occurred,
       tagged by the decision point.  Traffic Engineering Configuration Information

   Traffic Engineering (TE) is an important and often complex task of
   configuration management: the participating devices should be
   provided with the configuration information that will help them to
   select the appropriate routes that lead to a set of destinations,
   according to specific constraints and requirements that may have been
   dynamically negotiated with the customer.

   These constraints may be expressed in terms of time duration (e.g.,
   the use of a traffic-engineered route on a weekly basis), traffic
   characterization (e.g., all IP multicast traffic should be forwarded
   along a specific distribution tree), security concerns (e.g., use
   IPsec tunnels), and/or QoS considerations (e.g., EF (Expedited
   Forwarding)-marked traffic [RFC3246] should always use a subset of
   "EF-compliant" routes).  Configuration Information for Tunnel Design and Activation  Tunnel Identification Information

   The identification of a tunnel should be globally unique, especially
   if the tunnel is to be established and activated across autonomous
   systems.  The tunnel identification schemes (e.g., endpoint
   numbering) should be left to service providers, assuming that the
   corresponding formalism is commonly understood, whatever the number
   of autonomous systems the tunnel may cross.

   The tunnel identification information SHOULD at least be composed of
   the tunnel endpoint identification information.  The tunnel
   identification information MAY also be composed of an informal
   description of the tunnel, e.g., the purpose of its establishment,
   customer traffic that may be forwarded into this tunnel, etc.  Tunneling Protocol Configuration Information

   Any participating device MUST be provided with the configuration
   information related to the tunneling technique to be used for the
   establishment and the activation of the tunnel.  Such techniques
   include Generic Routing Encapsulation (GRE, [RFC2784]), IP Secure in

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   tunnel mode (IPsec, [RFC2401]), Layer 2 Tunneling Protocol (L2TP,
   [RFC2661]), etc.

8.3.  Global Management Requirements

8.3.1.  Fault Management

   Mechanisms to monitor and report any fault that affects service
   operation SHOULD be independent of the configuration protocol.

8.3.2.  Configuration Management

   Errors during a configuration procedure could impact the availability
   of a given service offering, while consistency checks are mandatory
   so as to correctly enforce a configuration policy.

   The following requirements have been identified:

   o  Provisioning of configuration information SHOULD be as automated
      as possible,
   o  Mechanisms to detect and diagnose configuration errors MUST be
   o  Consistency of configuration operations service-wise MUST be
   o  Simulation tools SHOULD be used to assess the validity of
      configuration information before it is downloaded to the relevant
      participant devices.
   o  Autonomic provisioning capabilities SHOULD be enabled to
      facilitate new device deployments in an automatic way, ideally
      without any human configuration intervention.  Of course, the
      procedure MUST be designed to allow for administrative validation
      under some events.  The purpose of allowing for such events is to
      ease troubleshooting and react to failures events when unexpected
      behaviors are experienced.
   o  Means to prevent against "mad robot" phenomena SHOULD be

8.3.3.  Performance Management

   Performance management is key for guaranteeing Service Assurance by
   proactively detecting network degradation.

   In a vendor-agnostic scenario, the mechanisms for performance
   management SHOULD implement standardized measurements among the
   involved devices, represented by abstract, standard data models.
   There are a number of measurements that can be taken into account for
   different purposes, such as CPP validation, bandwidth utilization or
   network and service level resilience.  To that end, the performance

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   management tools SHOULD provide reporting capabilities of the
   obtained measurements through counters or any other mean agnostic to
   specific vendor implementations.

   The activation (and de-activation) of the reporting capabilities MAY
   be enabled by using automated configuration mechanisms.

8.4.  Security Management

8.4.1.  Device Authentication

   It MUST be possible to activate mutual authentication between manager
   and managed entities.  The authentication MUST be checked before
   exchanging any configuration data, so as to prevent DoS (Denial of
   Service) attacks.

8.4.2.  Integrity of Configuration Information

   Two types of integrity MUST be provided.  The first one may be done
   at the network layer, e.g., by using the IPsec protocol suite.  The
   second type should protect configuration data at the application
   layer (e.g., the entire file configuration is integrity protected).

8.4.3.  Confidentiality of Exchanged Data

   The participating device SHOULD provide security functions that
   provide confidentiality.  Encryption algorithms MUST be standard and
   manually or automatically activated.

8.4.4.  Key Management

   The configuration system MUST provide a scalable key management
   scheme.  The number of keys to be managed must be at most linearly
   proportional to the number of the devices.

8.4.5.  Connection Log

   The participating device MUST log all configuration connections.  At
   least the following information must be provided:

   o  Identity of the device which provided the configuration
   o  Date of the connection,
   o  Identity of the user who has initiated the configuration process,
   o  Description of the configuration information that has been

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8.4.6.  Profiles

   The configuration system MUST allow the definition and the activation
   of several privilege levels.  Each level could be associated to a set
   of administrative functions.  Each configuration administrator could
   be assigned a specific access level to perform a (possibly limited)
   set of configuration tasks.

9.  IANA Considerations

   This document does not require any action from IANA.

10.  Security Considerations

   This document reflects a set of requirements as far as the design and
   the enforcement of configuration policies are concerned for
   (automated) service subscription, delivery and maintenance.  As such,
   the document addresses some security concerns that have been depicted
   in Section 8.4, and that SHOULD be taken into account when
   considering the specification of a protocol that will convey
   configuration information, as well as configuration information

11.  Acknowledgements

   Many thanks to M. Achemlal and Y. Adam who contributed to a first
   version of this text.

   Thanks for W. George for the comments.

12.  References

12.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2401]  Kent, S. and R. Atkinson, "Security Architecture for the
              Internet Protocol", RFC 2401, November 1998.

   [RFC2578]  McCloghrie, K., Ed., Perkins, D., Ed., and J.
              Schoenwaelder, Ed., "Structure of Management Information
              Version 2 (SMIv2)", STD 58, RFC 2578, April 1999.

   [RFC2661]  Townsley, W., Valencia, A., Rubens, A., Pall, G., Zorn,
              G., and B. Palter, "Layer Two Tunneling Protocol "L2TP"",
              RFC 2661, August 1999.

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   [RFC2748]  Durham, D., Boyle, J., Cohen, R., Herzog, S., Rajan, R.,
              and A. Sastry, "The COPS (Common Open Policy Service)
              Protocol", RFC 2748, January 2000.

   [RFC2784]  Farinacci, D., Li, T., Hanks, S., Meyer, D., and P.
              Traina, "Generic Routing Encapsulation (GRE)", RFC 2784,
              March 2000.

   [RFC3084]  Chan, K., Seligson, J., Durham, D., Gai, S., McCloghrie,
              K., Herzog, S., Reichmeyer, F., Yavatkar, R., and A.
              Smith, "COPS Usage for Policy Provisioning (COPS-PR)", RFC
              3084, March 2001.

   [RFC3159]  McCloghrie, K., Fine, M., Seligson, J., Chan, K., Hahn,
              S., Sahita, R., Smith, A., and F. Reichmeyer, "Structure
              of Policy Provisioning Information (SPPI)", RFC 3159,
              August 2001.

   [RFC3246]  Davie, B., Charny, A., Bennet, J., Benson, K., Le Boudec,
              J., Courtney, W., Davari, S., Firoiu, V., and D.
              Stiliadis, "An Expedited Forwarding PHB (Per-Hop
              Behavior)", RFC 3246, March 2002.

   [RFC6022]  Scott, M. and M. Bjorklund, "YANG Module for NETCONF
              Monitoring", RFC 6022, October 2010.

   [RFC6241]  Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
              Bierman, "Network Configuration Protocol (NETCONF)", RFC
              6241, June 2011.

12.2.  Informative References

              Boucadair, M., Jacquenet, C., and N. Wang, "IP/MPLS
              Connectivity Provisioning Profile", draft-boucadair-
              connectivity-provisioning-profile-02 (work in progress),
              September 2012.

              Boucadair, M. and C. Jacquenet, "Connectivity Provisioning
              Negotiation Protocol (CPNP)", draft-boucadair-
              connectivity-provisioning-protocol-01 (work in progress),
              October 2013.

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              Boucadair, M. and C. Jacquenet, "Software-Defined
              Networking: A Perspective From Within A Service Provider",
              draft-sin-sdnrg-sdn-approach-09 (work in progress),
              January 2014.

   [RFC3410]  Case, J., Mundy, R., Partain, D., and B. Stewart,
              "Introduction and Applicability Statements for Internet-
              Standard Management Framework", RFC 3410, December 2002.

   [RFC3444]  Pras, A. and J. Schoenwaelder, "On the Difference between
              Information Models and Data Models", RFC 3444, January

Authors' Addresses

   Mohamed Boucadair
   France Telecom
   Rennes  35000


   Christian Jacquenet
   France Telecom
   Rennes  35000


   Luis M. Contreras
   Telefonica I+D
   Ronda de la Comunicacion, s/n
   Madrid  28050


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