ETSI GS ENI 034 V4.1.1 (2024-07)

Experiential Networked Intelligence (ENI); Requirements and Detailed Procedure of Network Policy Conflict Detection

DGS/ENI-0034v411_Confli_Detect

General Information

• Status: Not Published
• Technical Committee: ENI - Experiential Networked Intelligence
• Current Stage: 12 - Citation in the OJ (auto-insert)
• Due Date: 24-Jul-2024
• Completion Date: 16-Jul-2024

Standards Content (Sample)

GROUP SPECIFICATION
Experiential Networked Intelligence (ENI);
Requirements and Detailed Procedure of
Network Policy Conflict Detection
Disclaimer
The present document has been produced and approved by the Experiential Networked Intelligence (ENI) ETSI Industry
Specification Group (ISG) and represents the views of those members who participated in this ISG.
It does not necessarily represent the views of the entire ETSI membership.

2 ETSI GS ENI 034 V4.1.1 (2024-07)

Reference
DGS/ENI-0034v411_Confli_Detect
Keywords
conflict detection, OAM, policy management
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3 ETSI GS ENI 034 V4.1.1 (2024-07)
Contents
Intellectual Property Rights . 4
Foreword . 4
Modal verbs terminology . 4
Executive summary . 4
Introduction . 4
1 Scope . 5
2 References . 5
2.1 Normative references . 5
2.2 Informative references . 5
3 Definition of terms, symbols and abbreviations . 5
3.1 Terms . 5
3.2 Symbols . 6
3.3 Abbreviations . 6
4 Overview of Network Policy Conflict Detection . 6
4.1 Introduction . 6
4.2 Description of Network Policy Conflict Detection . 6
4.3 External Requirements for Network Policy Conflict Detection . 7
4.3.1 Network Policy . 7
4.3.2 Input Frequency and Assisted System . 8
4.4 Functional Workflow . 9
5 Network Policy Conflict Detection Reference Working Pipeline . 10
5.1 Introduction . 10
5.2 Input . 10
5.2.1 User-defined Network Policy as Input . 10
5.2.2 Network Topo & Configuration as Input . 11
5.2.3 Forwarding Rule Changes or Self-Changes as Input . 11
5.3 Forwarding Rule Changes Simulation . 11
5.4 Network Policy Conflict Detecting and Locating . 12
5.4.1 Parser Layer Detecting and Locating . 12
5.4.2 Verifier Layer Detecting and Locating . 12
5.5 Result Feedback . 12
5.5.1 Parser Layer Feedback . 12
5.5.2 Verifier Layer Feedback . 13
6 Use Cases . 13
6.1 Network Policy Detection in VxLAN . 13
6.1.1 Use Case Context . 13
6.1.2 Description of the use case . 14
6.1.2.1 Overview . 14
6.1.2.2 Motivation . 14
6.1.2.3 Actors and Roles . 14
6.1.2.4 Initial context configuration . 14
6.1.2.5 Triggering condition. 14
6.1.2.6 Operational Flow of Actions . 14
6.1.2.7 Post-conditions . 15
7 Areas of Future Study (informative) . 15
7.1 Open Issues for the present document . 15
7.2 Issues for Future Study . 15
History . 16

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4 ETSI GS ENI 034 V4.1.1 (2024-07)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The declarations
pertaining to these essential IPRs, if any, are publicly available for ETSI members and non-members, and can be
found in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to
ETSI in respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the
ETSI Web server (https://ipr.etsi.org/).
Pursuant to the ETSI Directives including the ETSI IPR Policy, no investigation regarding the essentiality of IPRs,
including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not
referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become,
essential to the present document.
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Foreword
This Group Specification (GS) has been produced by ETSI Industry Specification Group (ISG) Experiential Networked
Intelligence (ENI).
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Executive summary
The present document specifies a high-level functional abstraction of the process of ENI Intent policy Multi-Stage
translating in an ENI system in terms of Functional Modules, Internal Reference Points and working pipelines.
Introduction
The present document defines a high-level functional abstraction of Network Policy Conflict Detection for ENI Intent
Policies. The organization of the present document is as follows. Clause 1 defines the scope of the present document.
Clauses 2 and 3 provide normative and informative references and definition of terms, respectively. Clause 4 provides
an informative overview of Network Policy Conflict Detection, including its motivation, benefits, important concepts
and an overview of its Functional Modules. Clause 5 defines important design principles of the processing. Clause 6
provides some use cases of Network Policy Conflict Detection. Clause 7 describes areas of future work.
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1 Scope
The present document provides additional information concerning Network Policy local conflict detection for ENI
Intent Policies. The present document expands on the work done in ETSI GS ENI 005 [i.2], clause 6.3.9.6.3, to provide
additional requirements and procedures to ensure that a new network policy will not conflict with any currently
deployed network policies in the same administrative domain. The present document is only intended for Network
Policies that are structured as ENI Intent Policies and which meet the requirements defined in clause 4.3.1.
The present document also describes the input(s), output(s), Internal Reference Points, and functionality of every step in
the Network Policy local conflict detection process.
If network policies with potential risks are dispatched, they may lead to various errors in the network and cause
instability and harm. However, as the scale of the network increases, the difficulty and cost of detecting and correcting
network errors also increases. Therefore, Network Policy Conflict Detection is implemented after Policy Validation and
Policy Rewriting. This will potentially save time and reduce misconfigurations. Consequently, the stability and
availability of the system will be increased.
The present document will encompass research and investigation activities that will address network policy conflict in
IP networks at the first stage. Subsequent efforts may extend the work into telecommunication networks.
2 References
2.1 Normative references
Not applicable.
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long-term validity.
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI GR ENI 004: "Experiential Networked Intelligence (ENI); Terminology".
[i.2] ETSI GS ENI 005 (V3.1.1): "Experiential Networked Intelligence (ENI); System Architecture".
[i.3] ETSI GR ENI 010: "Experiential Networked Intelligence (ENI); Evaluation of categories for AI
application to Networks".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the terms given in ETSI GR ENI 004 [i.1], ETSI GS ENI 005 [i.2] and the
following apply:
black hole: place in the network where incoming or outgoing traffic is unexcepted discarded, so that the data did not
reach its intended recipient
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forwarding loop: abnormal phenomenon in which a packet reaches the same device twice during the forwarding
process
forwarding model: edge-labelled directed graph for representing network forwarding behaviour
hit domain: set of packets that satisfy the Action rules
match domain: set of packets that match the routing table, ACL or NAT
network invariant: packet forwarding constraint that needs to be satisfied in any computer network
network policy: specific type of policy that affects network behaviour and can be directly understood and executed by
network devices within the Assisted System
self-change: unpredictable changes due to Network Events such as node faults
snapshot translation: kind of data translation in which the raw routing table (also known as flow table), ACL and NAT
of each device in the AS are translated into FW, ACL and NAT rules, respectively
User-Defined Network Policy: user-defined packet forwarding constraint that needs to be satisfied in a particular
computer network to comply with applicable network invariants
waypoint: device that the packets need to pass through during the forwarding process in addition to the source and
destination
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the abbreviations given in ETSI GR ENI 004 [i.1], ETSI GS ENI 005 [i.2]
and ETSI GR ENI 010 [i.3] apply.
4 Overview of Network Policy Conflict Detection
4.1 Introduction
This clause provides an informative introduction to Network Policy Conflict Detection in the ENI System Architecture.
Clause 4.2 describes the background and motivation of Network Policy Conflict Detection, and then provides a
high-level description of Network Policy Conflict Detection in the ENI System, including which ENI Functional Block
it is deployed in and what kind of policy it can and cannot validate. Clause 4.3 describes the external requirements for
Network Policy Conflict Detection, including the requirements for the network policy, the maximum input frequency of
Network Policy Conflict Detection, and the architecture of the Assisted System. Clause 4.4 describes the functional
architecture of Network Policy Conflict Detection in terms of Conflict Detection Functional Modules.
4.2 Description of Network Policy Conflict Detection
In an increasingly interconnected world, network traffic is increasingly diverse and demanding, whether it is
communication between small everyday devices on LANs or communication between large global data centres on the
Internet. This diversity in network traffic has driven the design and widespread adoption of a new open network
architecture called Software-Defined Networking (SDN). SDN is built upon programmable network switches, which
enable the separation of the network control plane from the data plane. This separation allows the control plane to
customize the data plane with User-Defined Policies that users want the network forwarding behaviour to meet.
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However, as network background traffic continues to evolve and new User-Defined Policies emerge, some of the
User-Defined Policies are likely to be violated after some forwarding rule changes due to rule conflicts or information
isolation between different applications. In addition to User-Defined Policies, network policies also can contain
Network Invariants that cannot be violated, including not having network Forwarding Loops and Black Holes. Network
invariance is one of the most easily violated network policies in complex computer networks, and it can easily be
caused by misconfiguration, hardware or software problems. Network Policy Conflict Detection is part of Intent
Processing in the Policy Management Functional Block, which aims to automatically detect network policy correctness
through telemetry information. More specifically, the Network Policy Conflict Detection with the forwarding rules
issued by the ENI System as input, maintains a network forwarding model to validate whether the installed forwarding
rules would violate Network Invariants or User-Defined Policies by extracting a specific forwarding slice from the
forwarding model.
In this context, the Network Policy Conflict Detection needs to process network invariants and user-defined network
policies. More specifically:
• Network Invariant: a property inherent to an object (e.g. a router interface) in a computer network that cannot
be violated. Examples include network Forwarding Loops and Black Holes.
• User-Defined Network Policy: this kind of policy represents additional user requirements for network
forwarding behaviour, including reachability, isolation and so on.
4.3 External Requirements for Network Policy Conflict
Detection
4.3.1 Network Policy
A detailed description of a User-Defined Network Policy is as follows:
For the purposes of the present document, a network forwarding model is used to represent the packet forwarding
behaviours of a data plane, which is an edge-labelled directed graph with a label on each directed edge to represent the
set of packets that can pass through this edge.

Figure 4-1: The Violation example of Network Invariants
Figure 4-1 illustrates two classic types of Network Invariant violations. The presented network has a total four devices,
where S1 and S2 denote programmable switches in the data plane, and H1 and H2 denote two hosts in the network.
NOTE 1: The label is omitted since the set of packets that can pass on all edges in the diagram is the same.
• Forwarding Loop violation. A device forwards a packet back to itself or to a previous node in the packet's
path. Figure 4-1(b) shows an example of a Forwarding Loop, where a Forwarding Loop S1-S2-S1 occurs when
a packet forwarded from S1 to S2 is forwarded by S2 to S1 again.
• Black Hole violation. A black hole is a place in the network where incoming or outgoing traffic is
unexpectedly discarded, so that the data did not reach its intended recipient. Figure 4-1(c) shows an example
of a Black Hole when packets from S1 and H2 are forwarded to S2, but S2 does not forward them to other
devices or intentionally drops them.
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