Internet-Draft | I2INF Framework | October 2024 |
Jeong, et al. | Expires 24 April 2025 | [Page] |
This document specifies a framework to define Interface to In-Network Functions (I2INF) for user services both on the network-level and application-level. In-Network Functions (INF) include In-Network Computing Functions (INCF), defined in the context of Network Functions Virtualization (NFV) and Software-Defined Networking (SDN). INF also includes In-Network Application Functions (INAF) which appear in the context of Internet-of-Things (IoT) Devices, Software-Defined Vehicles (SDV), and Unmanned Aerial Vehicles (UAV). This document describes an I2INF framework, which includes components and interfaces to configure and monitor the INFs that implement applications and services.¶
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Network softwarization has been widely adopted in multiple environments, such as in cloud and edge computing, as well as the in network infrastructure itself, facilitating the deployment of network services (e.g.,5G mobile networks [TS-23.501]). The multiple technologies behind network softwarization include Network Functions Virtualization (NFV) [ETSI-NFV][ETSI-NFV-Release-2] and Software-Defined Networking (SDN) [RFC7149]. Furthermore, there is also an integration with Intent-BasedNetworking (IBN)[RFC9315][Survey-IBN-CST-2023], which can be used to define and deploy intelligent network services as well as intelligent application services.¶
In the context of Computing in the Network (COIN) terminology [I-D.irtf-coinrg-coin-terminology], a Programmable Network Device (PND) in an In-Network Computing (INC) environment can have multiple kinds of features and capabilities. A PND can also interact with other PNDs. PNDs from different product lines or vendors can provide different functionalities for INC functions. In order to compose a COIN system consisting of multiple PDNs that interact among themselves, it is necessary to define a standard interface for PNDs to be exposed so that they can learn about each other's capabilities and properly interact with each other.¶
A standard framework to define the interfaces of Application Functions (AFs) and Network Functions (NFs) is required to allow the configuration and monitoring of applications and network services consisting of those functions. There is currently no standard data model to describe the capabilities of AFs and NFs. Furthermore, there is no standard data model defining an interface to register the capabilities of AFs and NFs with a controller-like device that would process service requests for those functions. In addition, there are no standard interfaces to configure and monitor those AFs and NFs according to a user's intent. The Interface to Network Security Functions (I2NSF) was standardized for the control and management of Network Security Services with Network Security Functions (NSFs) [RFC8329] [I-D.ietf-i2nsf-applicability]. The present document is defined taking into account the I2NSF document, but the purpose is beyond the scope of Security Functions, defining a more general control and management framework for intelligent services consisting of AFs and NFs.¶
This document specifies a framework for the definition of the Interface to In-Network Functions (I2INF) for In-Network Functions (INFs), assuming arbitrary functionalities, features and capabilities. The INFs consist of Network Functions (NFs) including PNDs and Application Functions (AFs) and are used to compose user services. First of all, INFs include In-Network Computing Functions (INCF) which are NFs, which are defined within the context of NFV and SDN [I-D.irtf-coinrg-use-cases]. Secondly, they also include In-Network Application Functions (INAF) which are AFs employed by Internet-of-Things (IoT) Devices, Software-Defined Vehicles (SDV) [AUTOSAR-SDV][Eclipse-SDV][COVESA], and Unmanned Aerial Vehicles (UAV). Finally, this document shows how Intent-Based Networking (IBN) can be realized with the proposed I2INF framework and its interfaces for user services that consist of a combination of INFs in a target network.¶
This document uses the terminology described in [RFC9315], [RFC8329], [I-D.irtf-coinrg-coin-terminology], [I-D.irtf-coinrg-use-cases], [I-D.jeong-i2nsf-security-management-automation], [I-D.jeong-nmrg-ibn-network-management-automation], and [I-D.yang-i2nsf-security-policy-translation]. In addition, the following terms are defined below:¶
Intent: A set of operational goals (that a network should meet) and outcomes (that a network is supposed to deliver) defined in a declarative manner without specifying how they are achieved or should be implemented [RFC9315].¶
Intent-Based System (IBS): A system that enforces an intent from a user (or administrator) into a target system (e.g., SDV). An intent can be expressed in Natural Language (e.g., English) and can be translated into a policy (i.e., network policy and application policy) using Natural Language Processing (NLP) [USENIX-ATC-Lumi][BERT] [Deep-Learning]. In this document, the intent can be translated into a corresponding high-level policy by an intent translator [I-D.jeong-i2nsf-security-management-automation]. The high-level policy can also be translated into the corresponding low-level policy by a policy translator [I-D.yang-i2nsf-security-policy-translation]. The low-level policy is dispatched to appropriate Service Functions (SFs). Through the monitoring of the SFs, the activity and performance of the SFs is monitored and analyzed. If needed, the rules of the high-level or low-level network policy are augmented or new rules are generated and configured to appropriate SFs.¶
Mobile Object (MO): An object that is capable of moving with its own power source and wireless communication capability such as 5G Vehicle-to-Everything (e.g., 5G V2X). An MO can be an Internet-of-Things (IoT) device, Software-Defined Vehicle (SDV) [AUTOSAR-SDV][Eclipse-SDV][COVESA], and Unmanned Aerial Vehicle (UAV). An MO is a Programmable Network Device (PND) [I-D.irtf-coinrg-coin-terminology] that can be reconfigured for different network requirements inside the MO.¶
In-Network Computing Functions (INCF): The service functions that work for computing in the network infrastructure. They are a group of COIN programs [I-D.irtf-coinrg-coin-terminology] to provide required computing tasks and functions.¶
In-Network Application Functions (INAF): The service functions that work for applications in Mobile Objects. They are a group of COIN programs [I-D.irtf-coinrg-coin-terminology] to provide the required application tasks and functions.¶
Interface to In-Network Functions (I2INF): Interfaces that are used between a pair of INFs for the interaction, configuration and monitoring.¶
A Framework for the Interface to In-Network Functions (I2INF): a framework that consists of components and interfaces to configure and monitor INFs that can be employed by applications and services in the network infrastructure and MOs.¶
This section specifies a framework for defining the Interface to In-Network Functions (I2INF), including its components and the interfaces among those components. Figure 1 shows Wireless and Wired Networks of a Central Cloud. The I2INF framework includes network entities and Mobile Objects (MO). Figure 2 shows a VNF-Consensus Architecture that allows the I2INF framework to synchronize flow table information of all the replicated SDN Controllers in the same Edge Cloud [NFV-COIN].¶
An intent-based management strategy is required between the central cloud and MOs to allow the automatic configuration of MOs [I-D.jeong-nmrg-ibn-network-management-automation]. Figure 3 shows an instance of the I2INF framework as an IBS for an MO. The framework in this case includes a Central Cloud and an MO. Figure 4 shows an I2INF framework as an IBS for an Edge Cloud. The framework in this case consists of a Central Cloud and an Edge Cloud.¶
A Central Cloud (CC) consists of an I2INF User (as network administrator), a Cloud Controller (which acts as an orchestrator for the central cloud), an I2INF Database (which is the main repository for INF management and monitoring information), and a Cloud Analyzer (as a monitoring data analyzer for MOs and ECs) such as Network Data Analytics Function (NWDAF) in 5G networks [TS-23.288][TS-29.520]. These and other components are defined next:¶
I2INF User: It is the software (e.g., web-browser-based user interface) used by I2INF administrators to deliver network intents to MO controllers and edge controllers. In the 3GPP intent-driven management service document, it is assumed that a network intent is configured by an intent data model [TS-28.312] [TR-28.812].¶
Cloud Controller: It is the main component responsible for the management and control of other system components of the central cloud, including security. From a security point of view, a security service policy can be transmitted to the service function (SF) by converting the I2INF User's security service intent into the corresponding security service policy and selecting an SF that provides an appropriate security service.¶
Cloud Vendor's Management System: It is a component that provides images of virtualized SFs for cloud services and registers the SFs and access information with the Cloud Controller.¶
Cloud Analyzer: It gathers and evaluates monitoring data from MO Analyzers and Edge Analyzers to ensure the functionality and performance of SFs, e.g., the network data analytics function (NWDAF) in 5G networks.¶
I2INF Database: It is a database for management information of MOs and ECs, including network and security configuration and status of MOs and ECs. For example, for MOs it maintains the current locations and navigation paths (e.g., SDVs). For ECs, it maintains network configuration information, including for instance the status of AFs and NFs within the edge cloud.¶
An IBS in an MO (or EC) is composed of an MO Controller (or Edge Controller) which acts as a manager for the MO (or EC), an MO Analyzer (or Edge Analyzer) which acts as a monitoring data analyzer for an MO (or EC)) [I-D.jeong-nmrg-ibn-network-management-automation], it can also include a Vendor's Management System (as a vendor system to provide cloud-native containers) [RFC8329], and Service Functions (SFs). SFs for the MO require NFs such as routers, DNS servers, and firewalls [I-D.jeong-nmrg-ibn-network-management-automation]), and AFs include safe driver devices and navigators. SFs for the EC include NFs such as VNF-Consensus, NFV-Failure-Detector, and NFV-RBCast (i.e., NFV Reliable-Ordered Broadcast) [NFV-COIN]). Those components are further described next:¶
MO Controller: a component that controls and manages other components of the MO framework (or the EC framework). It translates the high-level policies received from the Cloud Controller into a low-level policies that the SF can understand. Any SF can be selected to execute any low-level service. Yet another task is the transmission of the policy to the SF.¶
MO Vendor Management System (or Edge Vendor Management System): a component that provides an image of a virtualized SF for MO services (or EC services) to the MO framework (or the EC framework). Also responsible for registering functions and SF access control information on MO Controller (or the Edge Controller).¶
Service Function (SF): a component that can be either a virtual network function (VNF), cloud native network function (CNF), or physical network function (PNF) of a specific service. In the context of security, SFs provide security services such as firewalls, web filters, DDoS attack mitigators, and anti-viruses. In addition, networks and application services can also operate as SFs.¶
MO Analyzer (or Edge Analyzer): a component that collects monitoring data from SFs of MOs (or ECs) and analyzes the collected data to monitor the activity and performance of SFs. The MO Analyzer (or Edge Analyzer) acts as NWDAF of a 5G network. If there are problems (e.g., security attacks, traffic congestion, QoS degradation) in the MO network (or EC network), the MO Analyzer (or Edge Analyzer) requests either policy reconfigurations or feedback information to MO Controller (or Edge Controller) to restore security or troubleshoot the network.¶
Together with the I2INF framework, interfaces are also defined between pairs of system components in the central cloud and MO (or EC), respectively. These interfaces are shown in Figure 3 and Figure 4 and include the following:¶
Consumer-Facing Interface: the interface between I2INF User Internet and the Cloud Controller. This interface is used for communicating intents.¶
Controller-Facing Interface: the interface between the Cloud Controller and the MO Controller (or Edge Controller) for the transmission of high-level policies corresponding to translated intents.¶
SF-Facing Interface: the interface between the MO Controller (or Edge Controller) and SF for the transmission of translated lower-level policies.¶
Registration Interface: the interface used to transfer information about SF capabilities and access control for the registration of the SF with either the Cloud Controller or MO Controller (or Edge Controller). This interface is also used to deliver SF queries issued for searching for a requested SF. For an MO, this can be the interface between the Cloud Controller and the Cloud Vendor Management System (Cloud VMS), or between MO Controller and MO Vendor Management System (MO VMS). Also, for an EC, this can be the interface between the Cloud Controller and the Cloud Vendor Management System (Cloud VMS), or between Edge Controller and Edge Vendor Management System (Edge VMS).¶
Monitoring Interface: the interface between the SF and the MO Analyzer (or Edge Analyzer) used to collect the SF monitoring data and is employed to identify security, system, and network issues related to the SF.¶
Analytics Interface: the interface for the transmission of policy reconfigurations or feedback produced as a result of analyzing the SF monitoring data. For an MO, this is an interface between the MO Analyzer and MO Controller, or between the Cloud Analyzer and Cloud Controller. Also, for an EC, this is an interface between the Edge Analyzer and the Edge Controller, or between the Cloud Analyzer and the Cloud Controller.¶
Analyzer-Facing Interface: the interface between the MO Analyzer (or Edge Analyzer) and the Cloud Analyzer for the exchange of security, network, and system-related analysis of SFs.¶
VMS-Facing Interface: the interface between the Cloud VMS and the MO VMS (or Edge VMS) used to exchange SF feature information, such as SF container images.¶
Database Interface: the interface for exchanging data of an I2INF database. It is an interface between the I2INF Database and the Cloud Controller, or between the I2INF Database and the Cloud Analyzer.¶
The intents, high-level policies, and low-level policies can be either XML documents [RFC6020][RFC7950] or YAML documents [YAML]. They can be delivered to the destination components using NETCONF [RFC6241], RESTCONF [RFC8040], or REST API [REST].¶
As shown in Figure 3 and Figure 4, the I2INF Framework receives an intent from the I2INF User, entered by a user (who can be an administrator) into a target system such as an MO (e.g., SDV) or an Edge Cloud. The intent from the I2INF User can be translated into the corresponding high-level policy by an intent translator in the Cloud Controller of the Central Cloud [I-D.jeong-i2nsf-security-management-automation]. The high-level policy can also be translated into the corresponding low-level policy by a policy translator in the MO Controller of the MO or the Edge Controller of the Edge Cloud [I-D.yang-i2nsf-security-policy-translation]. For the MO, as shown in Figure 3, the low-level policy is dispatched from the MO Controller to the appropriate Service Functions (SFs) in the MO, examples of which include a Router or a Firewall. Also, in the context of the EC, as shown in Figure 4, the low-level policy is dispatched from the Edge Controller to appropriate Service Functions (SFs) in the EC, such as VNF-Consensus, NFV-Failure-Detector, and NFV-RBCast. Through the monitoring of the SFs, the activity and performance of the SFs in the MO (or EC) is monitored and analyzed by the MO Analyzer (or Edge Analyzer) in the MO (or EC). If needed, the rules of the high-level or low-level network policy can be augmented by the MO Analyzer (or Edge Analyzer). Also, new rules can be automatically generated and configured to appropriate SFs by the MO Analyzer (or Edge Analyzer).¶
In conclusion, this document proposed an I2INF framework as an IBS for both MOs and ECs. Through this IBS, the SFs (i.e., NFs and AFs) in the MOs and ECs can be configured and managed. Based on the proposed framework, both virtualized NFs and AFs can be efficiently orchestrated, also allowing agile resource reconfigurations and flexible updates.¶
This document does not require any IANA actions.¶
The same security considerations for the Interface to Network Security Functions (I2NSF) Framework [RFC8329] are applicable to the Intent-Based System this document.¶
The following changes are made from draft-jeong-opsawg-i2inf-framework-00:¶
This work was supported by Institute of Information & Communications Technology Planning & Evaluation (IITP) grant funded by the Korea Ministry of Science and ICT (MSIT) (No. RS-2024-00398199).¶
This work was supported in part by Institute of Information & Communications Technology Planning & Evaluation (IITP) grant funded by the Korea Ministry of Science and ICT (MSIT) (No. RS-2022-II221015, Development of Candidate Element Technology for Intelligent 6G Mobile Core Network).¶
This document is made by the group effort of OPWAWG, greatly benefiting from inputs and texts by Linda Dunbar (Futurewei), Yong-Geun Hong (Daejeon University), and Joo-Sang Youn (Dong-Eui University). The authors sincerely appreciate their contributions.¶
The following are coauthors of this document:¶