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Versions: (draft-merged-i2nsf-framework) 00 01 02 03 04 05 06 07 08 09 10 RFC 8329

Network Working Group                                          E. Lopez
Internet Draft                                                 Fortinet
Intended status: Informational                                 D. Lopez
Expires: January 2017                                        Telefonica
                                                               L. Dunbar
                                                            J. Strassner
                                                               X. Zhuang
                                                            China Mobile
                                                              J. Parrott
                                                             R Krishnan
                                                               S. Durbha

                                                           July 5, 2016

           Framework for Interface to Network Security Functions

Status of this Memo

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

   This Internet-Draft is submitted in full conformance with the
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   The list of current Internet-Drafts can be accessed at

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   Copyright (c) 2016 IETF Trust and the persons identified as the
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   This document describes the framework for the Interface to Network
   Security Functions (I2NSF), and defines a reference model (including
   major functional components) for I2NSF. Network security functions
   (NSFs) are packet-processing engines that inspect and optionally
   modify packets traversing networks, either directly or in the
   context of sessions in which the packet is associated.

Table of Contents

   1. Introduction...................................................3
   2. Conventions used in this document..............................4
   3. I2NSF Reference Model..........................................4
      3.1. Client Facing Interface...................................5
      3.2. NSFs Facing Interface.....................................6
      3.3. Registration Interface....................................7
   4. Threats Associated with Externally Provided NSFs...............8

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   5. Potential pitfalls to Avoid in Managing Flow-based NSFs........9
   6. The Network Connecting I2NSF Components.......................10
      6.1. Network connecting I2NSF Clients and I2NSF Controller....10
      6.2. Network Connecting the Security Controller and NSFs......10
      6.3. Interface to vNSFs.......................................11
   7. I2NSF Flow Security Policy Structure..........................12
      7.1. Client Facing Flow Security Policy structure.............13
      7.2. NSF Facing Flow Security Policy structure................14
      7.3. Difference from ACL data model...........................15
   8. Capability Negotiation........................................16
   9. Registration consideration....................................17
      9.1. Flow-based NSF Capability Characterization...............17
      9.2. Registration Categories..................................18
   10. Manageability Considerations.................................20
   11. Security Considerations......................................21
   12. IANA Considerations..........................................21
   13. References...................................................21
      13.1. Normative References....................................21
      13.2. Informative References..................................22
   14. Acknowledgments..............................................23

1. Introduction

   This document describes the framework for the Interface to Network
   Security Functions (I2NSF), and defines a reference model (including
   major functional components) for I2NSF, including an analysis of the
   threats implied by the deployment of NSFs that are externally
   provided. It also describes how I2NSF facilitates Software-Defined
   Networking (SDN) and Network Function Virtualization (NFV) control,
   while avoiding potential constraints that could limit the internal
   functionality and capabilities of NSFs.

   The I2NSF use cases ([I2NSF-ACCESS], [I2NSF-DC] and [I2NSF-Mobile])
   call for standard interfaces for clients (e.g., applications,
   overlay or cloud network management system, or enterprise network
   administrator or management system), to inform the network what they
   are willing to receive. I2NSF realizes this as a set of security
   rules for monitoring and controlling the behavior of their specific
   flows. It also provides standard interfaces for them to monitor the
   flow based security functions hosted and managed by different
   administrative domains.

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   [I2NSF-Problem] describes the motivation and the problem space for
   Interface to Network Security Functions.

2. Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in RFC-2119 [RFC2119].

   In this document, these words will appear with that interpretation
   only when in ALL CAPS. Lower case uses of these words are not to be
   interpreted as carrying RFC-2119 significance.

   BSS:  Business Support System

   Controller: used interchangeably with Service Provider Security
               Controller or management system throughout this

   FW:   Firewall

   IDS:  Intrusion Detection System

   IPS:  Intrusion Protection System

   NSF:  Network Security Functions, defined by [I2NSF-Problem]

   OSS:  Operation Support System

   vNSF: refers to NSF being instantiated on Virtual Machines.

3. I2NSF Reference Model

   The following figure shows a reference model (including major
   functional components) for I2NSF and the interfaces among those

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              |      I2NSF Client                                   |
              | E.g. Overlay Network Mgnt, Enterprise network Mgnt  |
              |  another network domain's mgnt, etc.                |
                         |  Client Facing Interface
                   |Network Operator mgmt|               +-------------+
                   | Security Controller | < --------- > | Developer's |
                   +---------------+-----+  Registration | Mgnt System |
                                   |         Interface   +-------------+
                                   | NSF Facing Interface
       |                                                   |
       |                                                   |
   +---+--+         +------+             +------+       +--+---+
   + NSF-1+ ------- + NSF-n+             +NSF-1 + ----- +NSF-m +  . . .
   +------+         +------+             +------+       +------+

   Developer A                                 Developer B

                        Figure 1: I2NSF Reference Model

3.1. Client Facing Interface

   The Client Facing Interface, which is often loosely called the north
   bound interface to the controller, is for clients to express and
   monitor security policies for clients' specific flows through an
   administrative domain.

   In today's world, where everything is connected, preventing unwanted
   traffic has become a key challenge. More and more networks,
   including various types of Internet of Things (IoT) networks,
   information-centric networks (ICN), content delivery networks (CDN),
   and cloud networks, are some form of overlay networks with their
   paths (or links) among nodes being provided by other networks
   (a.k.a. underlay networks). The overlay networks' own security
   solutions cannot prevent various attacks from saturating the access
   links to the overlay network nodes, which may cause overlay nodes'
   CPU/links too overloaded to handle their own legitimate traffic.

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   Very much like traditional networks placing firewall or intrusion
   prevention system (IPS) on the wire to enforce traffic rules,
   Interface to Network Security Functions (I2NSF) can be used by
   overlay networks to request certain flow-based security rules to be
   enforced by underlay networks. With this mechanism, unwanted
   traffic, including DDoS attacks, can be eliminated from occupying
   the physical links and ports to the overlay network nodes, thereby
   avoiding excessive or problematic overlay node CPU/storage/port
   utilization. The same approach can be used by enterprise networks to
   request their specific flow security policies to be enforced by the
   provider network that interconnect their users.

   Here are some examples of I2NSF clients:

   - A Videoconference network manager that needs to dynamically inform
     the underlay network to allow, rate-limit or deny flows (some of
     which are encrypted) based on specific fields in the packets for a
     certain time span.

   - Enterprise network administrators and management systems that need
     to request their provider network to enforce some rules to their
     specific flows.

   - A IoT management system sending requests to the underlay network
     to block flows that match their specific conditions.

3.2. NSFs Facing Interface

   The NSFs Facing Interface, which is often loosely called the south
   bound interface to the controller, specifies and monitors a number
   of flow based security policies to individual NSFs.  Note that the
   controller does not need to use all features for a given NSF, nor
   does it need to use all available NSFs. Hence, this abstraction
   enables the same relative features from diverse NSFs from different
   developers to be selected.

   Flow-based NSFs [I2NSF-Problem] inspects packets in the order that
   they are received. The Interface to Flow-based NSFs can be generally
   grouped into three types:

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      1) Configuration - deals with the management and configuration of
         the NSF device itself, such as port address configurations.
         Configuration deals with attributes that are relatively

      2) Signaling - which represents logging and query functions
         between the NSF and external systems. Signaling API functions
         may also be defined by other protocols, such as SYSLOG and

      3) Rule Provisioning - used to control the rules that govern how
         packets are treated by the NSFs. Due to the need of
         applications/controllers to dynamically control what traffic
         they need to receive, much of the I2NSF efforts towards
         interface development will be in this area.

   This draft proposes that a rule provisioning interface to NSFs can
   be developed on a flow-based paradigm. A common trait of flow based
   NSFs is in the processing of packets based on the content
   (header/payload) and/or context (session state, authentication
   state, etc) of the received packets.

3.3. Registration Interface

   NSFs provided by different developers may have different
   capabilities. In order to automate the process of utilizing multiple
   types of security functions provided by different developers, it is
   necessary to have an interface for developers to register their NSFs
   indicating the capabilities of their NSFs.

   The Registration Interface can be defined statically or instantiated
   dynamically at runtime. If a new functionality that is exposed to
   the user is added to an NSF, the developer MUST notify the network
   operator's management system or security controller of its updated
   functionality via the Registration Interface.

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4. Threats Associated with Externally Provided NSFs
   While associated with a much higher flexibility, and in many cases a
   necessary approach given the deployment conditions, the usage of
   externally provided NSFs implies several additional concerns in
   security.  The most relevant threats associated with a security
   platform of this nature are:
   o An unknown/unauthorized client can try to impersonate another
     client that can legitimately access external NSF services.  This
     attack may lead to accessing the policies and applications of the
     attacked client or to generate network traffic outside the
     security functions with a falsified identity.
   o An authorized client may misuse assigned privileges to alter the
     network traffic processing of other clients in the NSF underlay or
     platform.  This can become especially serious when such a client
     has higher (or even administration) privileges granted by the
     provider (the direct NSF provider, the ISP or the underlay network
   o A client may try to install malformed elements (policy or
     configuration), trying to directly take the control of a NSF or
     the whole provider platform, for example by exploiting a
     vulnerability on one of the functions, or may try to intercept or
     modify the traffic of other clients in the same provider platform.
   o A malicious provider can modify the software providing the
     functions (the operating system or the specific NSF
     implementations) to alter the behavior of the latter. This event
     has a high impact on all clients accessing NSFs as the provider
     has the highest level of privilege on the software in execution.
   o  A client that has physical access to the provider platform can
     modify the behavior of the hardware/software components, or the
     components themselves. Furthermore, it can access a serial console
     (most devices offer this interface for maintenance reasons) to
     access the NSF software with the same level of privilege of the
   Mutual authentication between the client and the NSF environment
   and, what is more important, the attestation of the elements in the
   NSF environment by clients could address these threats to an
   acceptable level of risk. Periodical attestation enables clients to
   detect alterations in the NSFs and their supporting infrastructure

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   able, and raises the degree of physical control necessary to perform
   an untraceable malicious modification of the environment.

5. Avoiding NSF Ossification

   An important concept underlying this framework is the fact that
   attackers do not have standards as to how to attack networks, so it
   is equally important not to constrain NSF developers to offering a
   limited set of security functions. In other words, the introduction
   of I2NSF standards should not make it easier for attackers to
   compromise the network. Therefore, in constructing standards for
   rules provisioning interfaces to NSFs, it is equally important to
   allow support for specific functions, as this enables the
   introduction of NSFs that evolve to meet new threats. Proposed
   standards for rules provisioning interfaces to NSFs SHOULD NOT:

      - Narrowly define NSF categories, or their roles when implemented
        within a network

      - Attempt to impose functional requirements or constraints,
        either directly or indirectly, upon NSF developers

      - Be a limited lowest common denominator approach, where
        interfaces can only support a limited set of standardized
        functions, without allowing for developer-specific functions

      - Be seen as endorsing a best common practice for the
        implementation of NSFs

   To prevent constraints on NSF developers' creativity and innovation,
   this document recommends the Flow-based NSF interfaces to be
   designed from the paradigm of processing packets in the network.
   Flow-based NSFs ultimately are packet-processing engines that
   inspect packets traversing networks, either directly or in the
   context of sessions in which the packet is associated. The goal is
   to create a workable interface to NSFs that aids in their
   integration within legacy, SDN, and/or NFV environments, while
   avoiding potential constraints which could limit their functional

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6. The Network Connecting I2NSF Components

 6.1. Network connecting I2NSF Clients and I2NSF Controller

     Editor's note: should we add the Remote Attestation to this

     As a general principle, in the I2NSF environment clients directly
     interact with the controller. Given the role of the Security
     Controller, a mutual authentication of clients and the Security
     Controller MUST be performed, establishing the desired level of
     assurance. This level of assurance will determine how stringent
     are the requirements for authentication (in both directions), and
     how detailed any other attestation procedures (as described in
     [Remote-Attestation]) will be.

     Upon successful mutual authentication, a trusted connection
     between the client and the Security Controller (or an endpoint
     designated by it) SHALL be established. All traffic to and from
     the NSF environment will flow through this connection.  The
     connection is intended not only to be secure, but trusted in the
     sense that it SHOULD be bound to the mutual authentication between
     client and Security Controller, as described in [Remote-
     Attestation], with the only possible exception of the application
     of the lowest levels of assurance, in which case the client MUST
     be made aware of this circumstance.

 6.2. Network Connecting the Security Controller and NSFs

     Most likely the NSFs are not directly attached to the I2NSF
     Controller; for example, NSFs can be distributed across the
     network. The network that connects the I2NSF Controller with the
     NSFs can be the same network that carries the data traffic, or can
     be a dedicated network for management purposes only. In either
     case, packet loss could happen due to failure, congestion, or
     other reasons.

     Therefore, the transport mechanism used to carry the control
     messages and monitoring information should provide reliable

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     message delivery.  Transport redundancy mechanisms such as
     Multipath TCP (MPTCP) [MPTCP] and the Stream Control Transmission
     Protocol (SCTP) [RFC3286] will need to be evaluated for
     applicability.  Latency requirements for control message delivery
     must also be evaluated.

     The network connection between the Security Controller and NSFs
     can rely either on:

     - Closed environments, where there is only one administrative
       domain.  Less restrictive access control and simpler validation
       can be used inside the domain because of the protected
     - Open environments, where some NSFs can be hosted in external
       administrative domains or reached via secure external network
       domains.  This requires more restrictive security control to be
       placed over the I2NSF interface.  The information over the I2NSF
       interfaces SHALL be exchanged used trusted channels as described
       in the previous section.

       When running in an open environment, I2NSF needs to provide
       identity information, along with additional data that
       Authentication, Authorization, and Accounting (AAA) frameworks
       can use. This enables those frameworks to perform AAA functions
       on the I2NSF traffic.

 6.3. Interface to vNSFs

     Even though there is no difference between virtual network
     security functions (vNSF) and physical NSFs from the policy
     provisioning perspective, there are some unique characteristics in
     interfacing to the vNSFs:

     - There could be multiple instantiations of one single NSF that
       has been distributed across a network. When different
       instantiations are visible to the Security Controller, different
       policies may be applied to different instantiations of an
       individual NSF (e.g., to reflect the different roles that each
       vNSF is designated for).

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     - When multiple instantiations of one single NSF appear as one
       single entity to the Security Controller, the policy
       provisioning has to be sent to the NSF's sub-controller, which
       in turn disseminates the polices to the corresponding
       instantiations of the NSF, as shown in the Figure 2 below.
     - Policies to one vNSF may need to be retrieved and moved to
       another vNSF of the same type when client flows are moved from
       one vNSF to another.
     - Multiple vNSFs may share the same physical platform
     - There may be scenarios where multiple vNSFs collectively perform
       the security policies needed.

                          | Security Controller    |
                                   ^        ^
                                   |        |
                       +-----------+        +------------+
                       |                                 |
                       v                                 v
    + - - - - - - - - - - - - - - - +  + - - - - - - - - - - - - - - - +
    |  NSF-A  +--------------+      |  |  NSF-B  +--------------+      |
    |         |Sub Controller|      |  |         |sub Controller|      |
    |         +--------------+      |  |         +--------------+      |
    | + - - - - - - - - - - - - - + |  | + - - - - - - - - - - - - - + |
    | |+---------+     +---------+| |  | |+---------+     +---------+| |
    | || NSF-A#1 | ... |  NSF-A#n|| |  | ||  NSF-B#1| ... |  NSF-B#m|| |
    | |+---------+     +---------+| |  | |+---------+     +---------+| |
    | |         NSF-A cluster     | |  | |          NSF-B cluster    | |
    | + - - - - - - - - - - - - - + |  | + - - - - - - - - - - - - - + |
    + - - - - - - - - - - - - - - - +  + - - - - - - - - - - - - - - - +

                Figure 2: Cluster of NSF Instantiations Management

7. I2NSF Flow Security Policy Structure

   Even though security functions come in a variety of form factors and
   have different features, provisioning to flow-based NSFs can be
   standardized by using Event - Condition - Action (ECA) policy

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   Event is used to determine whether the condition clause of the
   Policy Rule can be evaluated or not.

   A Condition, when used in the context of policy rules for flow-based
   NSFs, is used to determine whether or not the set of Actions in that
   Policy Rule can be executed or not. A condition can be based on
   various combinations of the content (header/payload) and/or the
   context (session state, authentication state, etc) of the received

   Action can be simple permit/deny/rate-limiting, applying specify
   profile, or establishing specific secure tunnels, etc.

 7.1. Client Facing Flow Security Policy structure

   This layer is for client's network management system to express and
   monitor the needed flow security policies for their specific flows.

   Some customers may not have security skills. As such, they are not
   able to express requirements or security policies that are precise
   enough. These customers may instead express expectations or intent
   of the functionality desired by their security policies. Customers
   may also express guidelines such as which certain types of
   destinations are not allowed for certain groups. As a result, there
   could be different depths or layers of Service Layer policies. Here
   are some examples of more abstract service layer security Policies:

          o Pass for Subscriber "xxx"
          o Enable basic parental control
          o Enable "school protection control"
          o Allow Internet traffic from 8:30 to 20:00
          o Scan email for malware detection protect traffic to
            corporate network with integrity and confidentiality
          o Remove tracking data from Facebook [website =
          o My son is allowed to access Facebook from 18:30 to 20:00

   One flow policy over Client Facing Interface may need multiple
   network functions at various locations to achieve the enforcement.
   Some flow Security policies from clients may not be granted because
   of resource constraints. [I2NSF-Demo] describes an implementation of

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   translating a set of client policies to the flow policies to
   individual NSFs.

   I2NSF will first focus on simple client policies that can be modeled
   as closely as possible to the flow security policies to individual
   NSFs.  The I2NSF simple client flow policies should have similar
   structure as the policies to NSFs, but with more of a client-
   oriented expression for the packet content, context, and other parts
   of an ECA policy rule. This enables the client to construct an ECA
   policy rule without having to know actual tags or addresses in the

   For example, when used in the context of policy rules over the
   Client Facing Interface:

     - An Event can be "the client has passed AAA process";
     - A Condition can be matching client Identifier, or from specific
       ingress or egress points; and
     - An action can be establishing a IPSec tunnel.

 7.2. NSF Facing Flow Security Policy structure

   The NSF Facing Interface is to pass explicit rules to individual
   NSFs to treat packets, as well as methods to monitor the execution
   status of those functions.

   Here are some examples of Events over the NSF facing interface:

     - time == 08:00,
     - a NSF state change from standby to active

   Here are some examples of Conditions over the NSF facing interface

     - Packet content values are based on one or more packet headers,
       data from the packet payload, bits in the packet, or something
       derived from the packet;
     - Context values are based on measured and inferred knowledge that
       define the state and environment in which a managed entity
       exists or has existed. In addition to state data, this includes
       data from sessions, direction of the traffic, time, and geo-
       location information. State refers to the behavior of a managed

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       entity at a particular point in time. Hence, it may refer to
       situations in which multiple pieces of information that are not
       available at the same time must be analyzed. For example,
       tracking established TCP connections (connections that have gone
       through the initial three-way handshake).

   Actions to individual flow-based NSFs include:

     - Action ingress processing, such as pass, drop, rate limiting,
       mirroring, etc.
     - Action egress processing, such as invoke signaling, tunnel
       encapsulation, packet forwarding and/or transformation.
     - Applying a specific Functional Profile or signature - e.g., an
       IPS Profile, a signature file, an anti-virus file, or a URL
       filtering file. Many flow-based NSFs utilize profile and/or
       signature files to achieve more effective threat detection and
       prevention. It is not uncommon for a NSF to apply different
       profiles and/or signatures for different flows. Some
       profiles/signatures do not require any knowledge of past or
       future activities, while others are stateful, and may need to
       maintain state for a specific length of time.

   The functional profile or signature file is one of the key
   properties that determine the effectiveness of the NSF, and is
   mostly NSF-specific today. The rulesets and software interfaces of
   I2NSF aim to specify the format to pass profile and signature files
   while supporting specific functionalities of each.

   Policy consistency among multiple security function instances is
   very critical because security policies are no longer maintained by
   one central security device, but instead are enforced by multiple
   security functions instantiated at various locations.

 7.3. Difference from ACL data model

   [ACL-MODEL] has defined rules for the Access Control List supported
   by most routers/switches that forward packets based on packets' L2,
   L3, or sometimes L4 headers. The actions for Access Control Lists
   include Pass, Drop, or Redirect.

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   The functional profiles (or signatures) for NSFs are not present in
   [ACL-MODEL] because the functional profiles are unique to specific
   NSFs. For example, most IPS/IDS implementations have their
   proprietary functions/profiles. One of the goals of I2NSF is to
   define a common envelop format for exchanging or sharing profiles
   among different organizations to achieve more effective protection
   against threats.

   The "packet content matching" of the I2NSF policies should not only
   include the matching criteria specified by [ACL-MODEL] but also the
   L4-L7 fields depending on the NSFs selected.

   Some Flow-based NSFs need matching criteria that include the context
   associated with the packets.

   The I2NSF "actions" should extend the actions specified by [ACL-
   MODEL] to include applying statistics functions, threat profiles, or
   signature files that clients provide.

8. Capability Negotiation

   It is very possible that the underlay network (or provider network)
   does not have the capability or resource to enforce the flow
   security policies requested by the overlay network (or enterprise
   network). Therefore, it is very important to have capability
   discovery or inquiry mechanism over the I2NSF Client Facing
   Interface for the clients to discover if the needed flow polices can
   be supported or not.

   When an NSF cannot perform the desired provisioning (e.g., due to
   resource constraints), it MUST inform the controller.

   The protocol needed for this security function/capability
   negotiation may be somewhat correlated to the dynamic service
   parameter negotiation procedure [RFC7297]. The Connectivity
   Provisioning Profile (CPP) template documented in RFC7297, even
   though currently covering only Connectivity requirements (but
   includes security clauses such as isolation requirements, non-via
   nodes, etc.), could be extended as a basis for the negotiation
   procedure. Likewise, the companion Connectivity Provisioning
   Negotiation Protocol (CPNP) could be a candidate to proceed with the
   negotiation procedure.

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   The "security as a service" would be a typical example of the kind
   of (CPP-based) negotiation procedures that could take place between
   a corporate customer and a service provider. However, more security
   specific parameters have to be considered.

9. Registration consideration

 9.1. Flow-based NSF Capability Characterization

   There are many types of flow-based NSFs. Firewall, IPS, and IDS are
   the commonly deployed flow-based NSFs. However, the differences
   among them are definitely blurring, due to technological capacity
   increases, integration of platforms, and new threats. At their core:
  . Firewall - A device or a function that analyzes packet headers and
     enforces policy based on protocol type, source address,
     destination address, source port, destination port, and/or other
     attributes of the packet header. Packets that do not match policy
     are rejected. Note that additional functions, such as logging and
     notification of a system administrator, could optionally be
     enforced as well.
  . IDS (Intrusion Detection System) - A device or function that
     analyzes packets, both header and payload, looking for known
     events. When a known event is detected, a log message is generated
     detailing the event. Note that additional functions, such as
     notification of a system administrator, could optionally be
     enforced as well.
  . IPS (Intrusion Prevention System) - A device or function that
     analyzes packets, both header and payload, looking for known
     events. When a known event is detected, the packet is rejected.
     Note that additional functions, such as logging and notification
     of a system administrator, could optionally be enforced as well.

   Flow-based NSFs differ in the depth of packet header or payload they
   can inspect, the various session/context states they can maintain,
   and the specific profiles and the actions they can apply. An example
   of a session is "allowing outbound connection requests and only
   allowing return traffic from the external network".

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 9.2. Registration Categories

   Developers can register their NSFs using Packet Content Match
   categories. The IDR Flow Specification [RFC5575] has specified 12
   different packet header matching types. More packet content matching
   types have been proposed in the IDR WG. I2NSF should re-use the
   packet matching types being specified as much as possible. More
   matching types might be added for Flow-based NSFS. Tables 1-4 below
   list the applicable packet content categories that can be
   potentially used as packet matching types by Flow-based NSFs:

     |         Packet Content Matching Capability Index          |
     | Layer 2       | Layer 2 header fields:                    |
     | Header        | Source/Destination/s-VID/c-VID/EtherType/.|
     |               |                                           |
     | Layer 3       | Layer  header fields:                     |
     |               |            protocol                       |
     | IPv4 Header   |            dest port                      |
     |               |            src port                       |
     |               |            src address                    |
     |               |            dest address                   |
     |               |            dscp                           |
     |               |            length                         |
     |               |            flags                          |
     |               |            ttl                            |
     |               |                                           |
     | IPv6 Header   |                                           |
     |               |            addr                           |
     |               |            protocol/nh                    |
     |               |            src port                       |
     |               |            dest port                      |
     |               |            src address                    |
     |               |            dest address                   |
     |               |            length                         |
     |               |            traffic class                  |
     |               |            hop limit                      |
     |               |            flow label                     |
     |               |            dscp                           |
     |               |                                           |
     | TCP           |            Port                           |
     | SCTP          |            syn                            |
     | DCCP          |            ack                            |
     |               |            fin                            |

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     |               |            rst                            |
     |               |          ? psh                            |
     |               |          ? urg                            |
     |               |          ? window                         |
     |               |            sockstress                     |
     |               | Note: bitmap could be used to             |
     |               |   represent all the fields                |
     |               |                                           |
     | UDP           |                                           |
     |               |            flood abuse                    |
     |               |            fragment abuse                 |
     |               |            Port                           |
     | HTTP layer    |                                           |
     |               |          | hash collision                 |
     |               |          | http - get flood               |
     |               |          | http - post flood              |
     |               |          | http - random/invalid url      |
     |               |          | http - slowloris               |
     |               |          | http - slow read               |
     |               |          | http - r-u-dead-yet (rudy)     |
     |               |          | http - malformed request       |
     |               |          | http - xss                     |
     |               |          | https - ssl session exhaustion |
     | IETF PCP      | Configurable                              |
     |               | Ports                                     |
     |               |                                           |
     | IETF TRAM     | profile                                   |
     |               |                                           |
     |               |                                           |
                      Table 1: Subject Capability Index

     |      context  matching Capability Index                   |
     | Session       |   Session state,                          |
     |               |   bidirectional state                     |
     |               |                                           |
     | Time          |   time span                               |
     |               |   time occurrence                         |
     | Events        |   Event URL, variables                    |
     | Location      |   Text string, GPS coords, URL            |

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     | Connection    |   Internet (unsecured), Internet          |
     |   Type        |   (secured by VPN, etc.), Intranet, ...   |
     |  Direction    |  Inbound, Outbound                        |
     |  State        |  Authentication State                     |
     |               |  Authorization State                      |
     |               |  Accounting State                         |
     |               |  Session State                            |

                      Table 2: Object Capability Index

     |      Action Capability Index                              |
     | Ingress port  |   SFC header termination,                 |
     |               |   VxLAN header termination                |
     |               |   Pass                                    |
     | Actions       |   Deny                                    |
     |               |   Mirror                                  |
     |               |   Simple Statistics: Count (X min; Day;..)|
     |               |   Client specified Functions: URL         |
     | Egress        |   Encap SFC, VxLAN, or other header       |
                      Table 3: Action Capability Index

     |      Functional profile Index                             |
     | Profile types |   Name, type, or                          |
     | Signature     |   Flexible Profile/signature URL          |
     |               | Command for Controller to enable/disable  |
     |               |                                           |
                     Table 4: Function Capability Index

10. Manageability Considerations

     Management of NSFs usually includes:

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        -               life cycle management and resource management of NSFs

        -               configuration of devices, such as address configuration,
          device internal attributes configuration, etc,

        -               signaling, and

        -               policy rules provisioning.

     I2NSF will only focus on the policy rule provisioning part, i.e.,
     the last bullet listed above.

11. Security Considerations

     Having a secure access to control and monitor NSFs is crucial for
     hosted security service. Therefore, proper secure communication
     channels have to be carefully specified for carrying the
     controlling and monitoring information between the NSFs and their
     management entity (or entities).

12. IANA Considerations

   This document requires no IANA actions. RFC Editor: Please remove
   this section before publication.

13. References

      13.1. Normative References

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

   [RFC3060] Moore, B, et al, "Policy Core Information Model (PCIM)",
             RFC 3060, Feb 2001.

   [RFC3460] Moore, B. "Policy Core Information Model (PCIM)
             Extensions", RFC3460, Jan 2003.

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   [RFC5575] Marques, P, et al, "Dissemination of Flow Specification
             Rules", RFC 5575, Aug 2009.

   [RFC7297] Boucadair, M., "IP Connectivity Provisioning Profile",
             RFC7297, April 2014.

       13.2. Informative References

   [I2NSF-ACCESS] A. Pastor, et al, "Access Use Cases for an Open OAM
             Interface to Virtualized Security Services", <draft-
             pastor-i2nsf-access-usecases-00>, Oct 2014.

   [I2NSF-DC] M. Zarny, et al, "I2NSF Data Center Use Cases", <draft-
             zarny-i2nsf-data-center-use-cases-00>, Oct 2014.

   [I2NSF-MOBILE] M. Qi, et al, "Integrated Security with Access
             Network Use Case", <draft-qi-i2nsf-access-network-usecase-
             00>, Oct 2014

   [I2NSF-Problem] L. Dunbar, et al "Interface to Network Security
             Functions Problem Statement", <draft-dunbar-i2nsf-problem-
             statement-01>, Jan 2015

   [ACL-MODEL] D. Bogdanovic, et al, "Network Access Control List (ACL)
             YANG Data Model", <draft-ietf-net-acl-model-00>, Nov 2014.

   [gs_NFV] ETSI NFV Group Specification, Network Functions
             Virtualizsation (NFV) Use Cases. ETSI GS NFV 001v1.1.1,

   [NW-2011] J. Burke, "The Pros and Cons of a Cloud-Based Firewall",
             Network World, 11 November 2011

   [SC-MobileNetwork] W. Haeffner, N. Leymann, "Network Based Services
             in Mobile Network", IETF87 Berlin, July 29, 2013.

   [I2NSF-Demo] Y. Xie, et al, "Interface to Network Security Functions
             Demo Outline Design", <draft-xie-i2nsf-demo-outline-
             design-00>, April 2015.

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   [ITU-T-X1036] ITU-T Recommendation X.1036, "Framework for creation,
             storage, distribution and enforcement of policies for
             network security", Nov 2007.

14. Acknowledgments

   Acknowledgements to xxx for his review and contributions.

   This document was prepared using 2-Word-v2.0.template.dot.

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Authors' Addresses

   Edward Lopez
   899 Kifer Road
   Sunnyvale, CA 94086
   Phone: +1 703 220 0988
   Email: elopez@fortinet.com

   Diego Lopez
   Email: diego.r.lopez@telefonica.com

   XiaoJun Zhuang
   China Mobile
   Email: zhuangxiaojun@chinamobile.com

   Linda Dunbar
   Email: Linda.Dunbar@huawei.com

   John Strassner

   Joe Parrott
   Email: joe.parrott@bt.com

   Ramki Krishnan
   Email: ramki_krishnan@dell.com

   Seetharama Rao Durbha
   Email: S.Durbha@cablelabs.com

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