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Concluded WG Interface to Network Security Functions (i2nsf)

Note: The data for concluded WGs is occasionally incorrect.

WG Name Interface to Network Security Functions
Acronym i2nsf
Area Security Area (sec)
State Concluded
Charter charter-ietf-i2nsf-01 Approved
Document dependencies
Additional resources Issue tracker, Wiki, Zulip stream
Personnel Chairs Linda Dunbar, Yoav Nir
Area Director Roman Danyliw
Mailing list Address
To subscribe

Closing note for Working Group Hi I2NSF WG! Congratulations on your efforts to document the I2NSF architecture and specify the supporting models to implement it. This took a sustained engagement and significant community engagement. Thank you for a job well done! With the last of planned work items just approved and consistent with discussions at IETF 113-116, the WG is being closed. The mailing list ( ) will remain open for discussion of any errata or implementation issues that might arise; and the list archive will remain online. Additionally, the I2NSF datatracker entry will also stay active ( Regards, Roman (Responsible AD for I2NSF)

Final Charter for Working Group

A Network Security Function (NSF) is a function used to ensure integrity, confidentiality, or availability of network communications, to detect unwanted network activity, or to block or at least mitigate the effects of unwanted activity. NSFs are provided and consumed in increasingly diverse environments. Users could consume network security services enforced by NSFs hosted by one or more providers, which may be their own enterprise, service providers, or a combination of both. Similarly, service providers may offer their customers network security services that are enforced by multiple security products, functions from different vendors, or open source technologies. NSFs may be provided by physical and/or virtualized infrastructure. Without standard interfaces to control and monitor the behavior of NSFs, it has become virtually impossible for providers of security services to automate service offerings that utilize different security functions from multiple vendors.

The goal of I2NSF is to define a set of software interfaces and data models for controlling and monitoring aspects of physical and virtual NSFs, enabling clients to specify rulesets. If the working group finds it necessary to work on an information model before the data models, to help provide guidance and derive the data models, it may do so. The working group will decide later whether the information model needs to be published as an RFC. Other aspects of NSFs, such as device or network provisioning and configuration, are out of scope. As there are many different security vendors or open source technologies supporting different features and functions on their devices, I2NSF will focus on flow-based NSFs that provide treatment to packets/flows, such as Intrusion Protection/Detection System (IPS/IDS), web filtering, flow filtering, deep packet inspection, or pattern matching and remediation.

Controlling and monitoring aspects of NSFs include the ability to specify rules (by a single controller at the first phase), query, and monitor NSFs by one or more management entities. The initial phase of I2NSF will only consider one single controller that can specify or change rules to NSFs because multi-headed control requires the coordination to avoid potential conflict of rules. The NSFs can be monitored by multiple entities, but the database update and synchronization among multiple management entities are out of scope for I2NSF.

I2NSF will specify interfaces at two functional levels for the control and monitoring of network security functions:

The I2NSF Capability Layer specifies how to control and monitor NSFs at a functional implementation level. The term "Functional Implementation" is used to emphasize that the rules (for control and monitor) of NSFs have to be implementable by most NSFs. I2NSF will standardize a set of interfaces by which a security controller can invoke, operate, and monitor NSFs.

The I2NSF Service Layer defines how clients' security policies may be expressed to a security controller. The controller implements its policies according to the various capabilities provided by the I2NSF Capability Layer. The I2NSF Service Layer also allows the client to monitor the client specific policies.

A client may leverage the I2NSF Service Layer interface to express security policies to a security controller, which in turn interacts with one or more NSFs through the I2NSF Capability Layer interface. Alternatively, a client may interact with one or more NSFs directly through the I2NSF Capability Layer interface.

Since there could be many depths or types of Service Layer policies, the following bullets further clarify the scope of I2NSF:
o Only the simple Service Layer policies that are modeled as closely as possible on the Capability Layer are within the scope.
Simple Service Layer policies can be directly translated to capability layer rules with a direct mapping that might include a customer ID to be translated to tags carried by packets, but might not specify the NSF. This flexibility in the simple Service Layer enables a security controller to handle issues like multi-tenancy and the choice between available NSFs for a given policy.
o I2NSF will not specify abstract or sophisticated policies from clients. Expressing policies in ways other than the model used by the Capability Layer is out of scope.
o The translation mechanism/methods from Service Layer policies to Capability layer commands are out of scope for I2NSF.
However, I2NSF will provide a discussion forum for Informational drafts on data models, APIs, etc. that demonstrate how more complex Service Layer policies and formats may be translated to Capability Layer functions. Such documents would be pursued outside the WG.

Standard interfaces for monitoring and controlling the behavior of NSFs are essential building blocks for providers of security service to automate the use of different NSFs from multiple vendors. This work will leverage the existing protocols and data models defined by the I2RS, NETCONF, and NETMOD working groups. If extensions to these protocols or data models are needed, requirements will be developed by this WG, and the extensions will be developed in cooperation with the working groups responsible for the protocols.

The I2NSF working group's deliverables include:

o A single document covering use cases, problem statement, and gap analysis document. This document will initially be produced for reference as a living list to track and record discussions: the working group may decide to not publish this document as an RFC.
o A framework document, presenting an overview of the use of NSFs and the purpose of the models developed by the working group. This document will also be a reference text to guide the main work and the working group may decide to not publish this document as an RFC.
o If the working group considers it necessary, a single, unified, Information Model to describe the control and monitoring of flow-based NSFs.
o YANG data models for the control and monitoring of NSFs.
o A vendor-neutral vocabulary  to enable the characteristics and behavior of NSFs to be specified without requiring the NSFs themselves to be standardized, so that "security controller" or "manager" have a common base to choose the appropriate NSFs (by different vendors) that can fulfill the requests requested by clients.
o An examination of existing secure communication mechanisms to identify the appropriate ones for carrying the controlling and monitoring information between the NSFs and their management entities. This document may also be produced as a working document that is not published as an RFC.

The working group may additionally choose to develop documents to describe requirements for extensions (if any) to existing protocols used by the working group, to explain how the data models are used to monitor and control flow-based NSFs, and to describe how to use I2RS and NETCONF to carry the content of the data models. These documents may be published as Informational RFCs or may be working documents that are discarded once they have triggered the necessary work.

The working group will work closely with the I2RS, NETCONF, and NETMOD WGs. The working group will communicate with external SDOs like ETSI NFV and will encourage open source code development related to the working group scope in organizations like ONF, OpenStack, ODL, and OPNFV.

The working group must have the above deliverables completed within 24 months. The responsible AD will close the working group at that time if they are not completed or close to completion. The working group may be closed earlier if substantial progress is not being made.


Date Milestone Associated documents
Feb 2019 Working group re-charter or close
Feb 2019 Adopt IANA registry consideration as WG document
Dec 2018 Data Models and Applicability Statements to IESG for publication
Dec 2016 Adopt examination of existing secure communication mechanisms as WG document

Done milestones

Date Milestone Associated documents
Done All early drafts to IESG for publication (if WG decided to proceed): use cases, problem statement, and gap analysis document; framework document; information model requirements for extensions to protocols document; examination of existing secure communication mechanisms document
Done Adopt applicability statements as WG Document
Done Adopt data models as WG document
Done Adopt info model as WG document (if desired)
Done WG decides whether to progress adopted drafts for publication as RFCs (use cases, framework, information model, and examination of existing secure communication mechanisms)
Done Adopt requirements for extensions to protocols as WG document
Done Adopt framework as WG document
Done Adopt use Cases, problem statement, and gap analysis as WG document