No Working Group A. Galis Internet-Draft University College London Intended Status: Standards Track K. Makhijani Expires: September 6, 2018 D. Yu B. Liu Huawei Technologies March 5, 2018 Autonomic Slice Networking draft-galis-anima-autonomic-slice-networking-04 Abstract This document describes the technical requirements and the related reference model for the intercommunication and coordination among devices in Autonomic Slicing Networking. The goal is to define how the various elements in a network slicing context work and orchestrate together, to describe their interfaces and relations. While the document is written as generally as possible, the initial solutions are limited to the chartered scope of the WG. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts can be accessed at https://www.ietf.org/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at https://www.ietf.org/shadow.html Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on September 6, 2017. Copyright Notice Galis, et al. Expires September 6 , 2018 [Page 1] INTERNET DRAFT Autonomic Slice Networking March 2018 Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. The Network Slicing Overall View . . . . . . . . . . . . . . . 3 2.1. Key Terms and Context . . . . . . . . . . . . . . . . . . 3 2.2. High Level Requirements . . . . . . . . . . . . . . . . . 6 3. Autonomic Slice Networking . . . . . . . . . . . . . . . . . . 8 4. Autonomic Inter-Slice Orchestration . . . . . . . . . . . . . 11 5. GRASP Resource Reservation / Release Messages flow . . . . . . 12 6. The Autonomic Network Slicing Element . . . . . . . . . . . . 13 7. The Autonomic Slice Networking Ianfrastructure . . . . . . . . 15 7.1. Signaling Between Autonomic Slice Element Managers . . . . 15 7.2. The Autonomic Control Plane . . . . . . . . . . . . . . . 17 7.3. Naming & Addressing . . . . . . . . . . . . . . . . . . . 17 7.4. Discovery . . . . . . . . . . . . . . . . . . . . . . . . 17 7.5. Routing . . . . . . . . . . . . . . . . . . . . . . . . . 17 8. Security and Trust Infrastructure . . . . . . . . . . . . . . 17 8.1. Public Key Infrastructure . . . . . . . . . . . . . . . . 17 8.2. Domain Certificate . . . . . . . . . . . . . . . . . . . . 17 9. Cross-Domain Functionality . . . . . . . . . . . . . . . . . . 18 10. Autonomic Service Agents (ASA) . . . . . . . . . . . . . . . 18 11. Management and Programmability . . . . . . . . . . . . . . . 18 11.1. How a Slice Network Is Managed . . . . . . . . . . . . . 18 11.2. Autonomic Resource Information Model . . . . . . . . . . 19 11.3. Control Loops . . . . . . . . . . . . . . . . . . . . . . 19 11.4. APIs . . . . . . . . . . . . . . . . . . . . . . . . . . 19 11.4.1. Slice Control APIs . . . . . . . . . . . . . . . . . 19 11.4.2. Service Agent - Device APIs . . . . . . . . . . . . . 19 11.4.3. Service Agent - Port APIs . . . . . . . . . . . . . . 19 11.4.4. Service Agent - Link APIs . . . . . . . . . . . . . . 20 11.5. Relationship with MANO . . . . . . . . . . . . . . . . . 20 12. Security Considerations . . . . . . . . . . . . . . . . . . . 20 12.1. Threat Analysis . . . . . . . . . . . . . . . . . . . . . 20 12.2. Security Mechanisms . . . . . . . . . . . . . . . . . . . 20 13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20 Galis, et al. Expires September 6 , 2018 [Page 2] INTERNET DRAFT Autonomic Slice Networking March 2018 14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 20 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 20 14.1. Normative References . . . . . . . . . . . . . . . . . . 20 14.2. Informative References . . . . . . . . . . . . . . . . . 21 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 24 1 Introduction The document "Autonomic Networking - Definitions and Design Goals" [RFC7575] explains the fundamental concepts behind Autonomic Networking, and defines the relevant terms in this space, as well as a high level reference model. This document defines this reference model with more detail, to allow for functional and protocol specifications to be developed in an architecturally consistent, non- overlapping manner. While the document is written as generally as possible, the initial solutions are limited to the chartered scope of the WG. Most networks will run with some autonomic functions for the full networks or for a group of nodes [RFC7576] or for a group of slice networks while the rest of the network is traditionally managed. The goal of this document is to focus on the autonomic slicing networking. [RFC7575] is focusing on fully or partially autonomic nodes or networks. The proposed revised ANIMA reference model allows for this hybrid approach across all such capabilities. It enhances [ASN]. This is a living document and will evolve with the technical solutions developed in the ANIMA WG. Sections marked with (*) do not represent current charter items. While this document must give a long term architectural view, not all functions will be standardized at the same time. 2. The Network Slicing Overall View 2.1. Key Terms and Context A number of slice definitions were used in the last 10 years in distributed and federated testbed research [GENI], future internet research [ChinaCom09] and more recently in the context of 5G research [NGMN], [ONF], [IMT2020], [NGS-3GPP], [NS-ETSI]. Such definitions converge towards NS as group of components: Service Instance, Network Slice Instance, Resources and Slice Element Manager Galis, et al. Expires September 6 , 2018 [Page 3] INTERNET DRAFT Autonomic Slice Networking March 2018 In this draft we are using the following terms: Logical resource - An independently manageable partition of a physical resource, which inherits the same characteristics as the physical resource and whose capability is bound to the capability of the physical resource. It is dedicated to a Network Function or shared between a set of Network Functions. Virtual resource - An abstraction of a physical or logical resource, which may have different characteristics from that resource, and whose capability may not be bound to the capability of that resource Network Function (NF) - A processing function in a network. It includes but is not limited to network nodes functionality, e.g. session management, mobility management, switching, routing functions, which has defined functional behaviour and interfaces. Network functions can be implemented as a network node on a dedicated hardware or as a virtualized software functions. Data, Control, Management, Orchestration planes functions are Network Functions. Virtual Network Function (VNF) - A network function whose functional software is decoupled from hardware. One or more virtual machines running different software and processes on top of industry-standard high-volume servers, switches and storage, or cloud computing infrastructure, and capable of implementing network functions traditionally implemented via custom hardware appliances and middle. boxes (e.g. router, NAT, firewall, load balancer, etc.) Network Slicing (NS) refers to a managed group of subsets of resources, network functions / network virtual functions at the data, control, management/orchestration planes and services at a given time. Network slice is programmable and has the ability to expose its capabilities. The behaviour of the network slice realized via network slice instance(s). Network resources include connectivity, compute, and storage resources. Network Slicing is end-to-end concept covering the radio and non- radio networks inclusive of access, core and edge / enterprise networks. It enables the concurrent deployment of multiple logical, self-contained and independent shared or partitioned networks on a common infrastructure platform Network slicing represents logically or physically isolated groups of network resources and network function/virtual network functions configurations separating its behavior from the underlying physical network. Network Slice Instance - An activated network slice. It is created based on network template. A set of managed run-time network Galis, et al. Expires September 6 , 2018 [Page 4] INTERNET DRAFT Autonomic Slice Networking March 2018 functions, and resources to run these network functions, forming a complete instantiated logical network to meet certain network characteristics required by the service instance(s). It provides the network characteristics that are required by a service instance. A network slice instance may also be shared across multiple service instances provided by the network operator. From a business point of view, a slice includes combination of all relevant network resources / functions / assets required to fulfill a specific business case or service, including OSS, BSS and DevOps processes. From the network infrastructure point of view, slicing instances require the partitioning and assignment of a set of resources that can be used in an isolated, disjunctive or non- disjunctive manner. Examples of physical or virtual resources to be shared or partitioned would include: bandwidth on a network link, forwarding tables in a network element (switch, router), processing capacity of servers, processing capacity of network or network clouds elements [SLICING]. As such slice instances would contain: (i) a combination/group of the above resources which can act as a network, (ii) appropriate resource abstractions, (iii) capability exposure of abstract resources towards service and management clients that are needed for the operation of slices The capability exposure creates an abstraction of physical network devices that would provide information and information models allowing operators to manipulate the network resources. By utilizing open programmable network interfaces, it would enable access to control layer by customer interfaces and applications. The establishment of slices is both business-driven (i.e. slices are in support for different types and service characteristics and business cases) and technology-driven as slice is a grouping of physical or virtual) resources (network, compute, storage) which can act as a sub network and/or a cloud. A slice can accommodate service components and network functions (physical or virtual) in all network segments: access, core and edge / enterprise networks. A complete slice is composed of not only various network functions which are based on virtual machines at C-RAN and C-Core, but also transport network resources that can be assigned to the slice at radio access/transport network. Different future businesses require different throughput, delay and mobility, and some businesses need very high throughput or/and low delay. Galis, et al. Expires September 6 , 2018 [Page 5] INTERNET DRAFT Autonomic Slice Networking March 2018 2.2. High Level Requirements Slice creation: management plane create virtual or physical network functions and connects them as appropriate and instantiate them in the slice, which is a subnetworks. The instance of slice management then takes over the management and operations of all the (virtualised) network functions and network programmability functions assigned to the slice, and (re-)configure them as appropriate to provide the end-to-end service. A complete slice is composed of not only various network functions which are based on virtual machines at C-RAN and C-Core, but also transport network resources that can be assigned to the slice at radio access/transport network. Different future businesses [5GNS], [PER-NS] require different throughput, delay and mobility, and some businesses need very high throughput or/and low delay. Transport network shall provide QoS isolation, flexible network operation and management, and improve network utilization among different business. (1) Separation from partition of the physical network: Network slicing represents logically or physically isolated groups of network resources and network function/virtual network functions configurations separating its behavior from the underlying physical network. (2) QoS Isolation: Although traditional VPN technology can provide physical network resource isolation across multiple network segments, it is deemed far less capable of supporting QoS hard isolation, Which means QoS isolation on forwarding plane requires better coordination with management plane. (3) Independent Management Plane: Like above, network isolation is not sufficient, a flexible and more importantly a management plane per instance is required to operate on a slice independently and autonomously within the constraints of resources allocated to the slice. (4) Another flexibility requirement is that an operator can deploy their new business application or a service in network slice with low cost and high speed, and ensure that it does not affect existing of business applications adversely. (5) Stringent Resource Characteristics: A Network Slicing aware infrastructure allows operators to use part of the network resources to meet stringent resource characteristics. (6) Type of resources: Network Slice instance is a dedicated network Galis, et al. Expires September 6 , 2018 [Page 6] INTERNET DRAFT Autonomic Slice Networking March 2018 that is build and activated on an infrastructure mainly composed of, but not limited to, connectivity, storage and computing. (7) Programmability: Operator not only can slice a common physical infrastructure into different logical networks to meet all kinds of new business requirements, but also can use SDN based technology to improve the overall network utilization. By providing a flexible programmable interface; the 3rd party can develop and deploy new network business rapidly. Further, if a network slicing can run with its own slice controller, this network slicing will get more granular control capability [I- D.ietf-anima-autonomic-control-plane] to retrieve slice status, and issuing slicing flow table, statistics fetch etc. (8) Life cycle self-management: It includes creation, operations, re- configuration, composition, decomposition, deletion of slices. It would be performed automatically, without human intervention and based on a governance configurable model of the operators. As such protocols for slice set-up /operations /(de)composition / deletion must also work completely automatically. Self-management (i.e. self- configuration, self- composition, self-monitoring, self-optimisation, self- elasticity) is carried as part of the slice protocol characterization. (9) Network slice Self-management: Network slices will need to be self-managed by automated, autonomic and autonomous systems in order to cope with dynamic requirements, such as flexible scalability, extensibility, elasticity, residency and reliability of an infrastructure. Network slices will need to be self-managed by automated, autonomic and autonomous systems in order to cope with dynamic requirements, such as scalability or extensibility of an infrastructure. A common information model describing uniformly the NS in a single and/or multiple domain would support such self-managed. (10) Extensibility: Since the Autonomic Slice Networking Infrastructure is a relatively new concept, it is likely that changes in the way of operation will happen over time. As such new networking functions will be introduced later, which allow changes to the way the slices operate. (11) Network Slice elasticity: A Network Slice instance has the mechanisms and triggers for the growth/shrinkage of all resources, and/or network and service functions as enabled by a common information model that explicitly provides for elasticity policies for scaling up/down resources. Galis, et al. Expires September 6 , 2018 [Page 7] INTERNET DRAFT Autonomic Slice Networking March 2018 (12) Multiple domains activation: Network slice instances are concurrently activated as multiple logical, self-contained and independent, partitioned network functions and resources on a specific infrastructure domain. (13) Resource Exposure: Each network slice has the ability to dynamically expose and possibly negotiate the parameters that characterize an NS as enabled by a common information model that explicitly provides monitoring policies for all model descriptors. (14) Network Tenants: Network slicing support tenants that are strongly independent on infrastructure as enabled by a common information model that explicitly provides for a level of tenants management for the resources dedicated to an instance of network slice. (15) End-to-end Orchestration of Network Slicing: Coordinating underlay network infrastructure and service function resources. In the process of orchestration of network slice, resource registration and templates for network slice repository are needed. 3. Autonomic Slice Networking This section describes the various elements in a network with autonomic functions, and how these entities work together, on a high level. Subsequent sections explain the detailed inside view for each of the autonomic network elements, as well as the network functions (or interfaces) between those elements. From a business point of view, a slice includes a combination of all the relevant network resources, functions, and assets required to fulfill a specific business case or service, including OSS, BSS and DevOps processes. From the network infrastructure point of view, network slice requires the partitioning and assignment of a set of resources that can be used in an isolated, disjunctive or non- disjunctive manner for that slice. From the tenant point of view, network slice provides different capabilities, specifically in terms of their management and control capabilities, and how much of them the network service provider hands over to the slice tenant. As such there are two kinds of slices: (A) Inner slices, understood as the partitions used for internal services of the provider, retaining full control and management of them. (B) Galis, et al. Expires September 6 , 2018 [Page 8] INTERNET DRAFT Autonomic Slice Networking March 2018 Outer slices, being those partitions hosting customer services, appearing to the customer as dedicated networks. Network Slicing lifecycle includes the management plane selecting a group of network resources (whereby network resources can be physical, virtual or a combination thereof); it connects with the physical and virtual network and service functions as appropriate, and it instantiates all of the network and service functions assigned to the slice. For slice operations, the control plane takes over governing of all the network resources, network and service functions assigned to the slice. It (re-) configures them as appropriate and as per elasticity needs, in order to provide an end-to-end service. One expected autonomic Slice Networking function is the capability and resource Usability for a slice. Applications or services requiring information of available slice capabilities and resources are satisfied by abstracted resource view and control. Usability of capabilities and resources can be enabled either by resource publishing or by discovery. In the latter case, the service performs resource collection directly from the provider of the slice by using discovery mechanisms to get total information about the available resources to be consumed. In the former, the network provider exposes available resources to services (e.g., through a resource catalog) reducing the amount of detail of the underlying network. Slice Element Manager (SEM) is installed for each control domain. Control domain is defined according to geographic location and control functions. Each SEM converts requirements from orchestrator into virtual resources and manages virtual resources of a slice. SEM also exchanges information of virtual resources with other slice element managers via a dedicated resource interface. SEM provides also capability exposure facilities by allowing 3rd parties to access / use via APIs information regarding services provided by the slice (e.g. connectivity information, QoS, mobility, autonomicity, etc.) and to dynamically customize the network characteristics for different diverse use cases (e.g. ultra-low latency, ultra- reliability, value-added services for enterprises, etc.) within the limits set of functions by the operator. Physical Element Manager (PEM) is installed for each control domain. Control domain is defined according to geographic location and control functions. PEM exchanges information of virtual resource with SEM via virtual resource interface and interconverts between virtual resource and physical resource. The PEM orders physical functions (ex. switches) to allocate physical resource via physical resource interface. Figure 1 shows the high level view of an Autonomic Slice Networking. Galis, et al. Expires September 6 , 2018 [Page 9] INTERNET DRAFT Autonomic Slice Networking March 2018 It consists of a number of autonomic nodes resources, which interact directly with each other. Those autonomic nodes resources provide a common set of capabilities across a network slice, called the "Autonomic Slice Networking Infrastructure" (ASNI). The ASN provides functions like naming, addressing, negotiation, synchronization, discovery and messaging. Autonomic network functions typically span several slices in the network. The atomic entities of an autonomic function are called the "Autonomic Service Agents" (ASA), which are instantiated on slices. In a horizontal view, autonomic functions span across the network, as well as the Autonomic Slice Networking Infrastructure. In a vertical view, a slice always implements the ASNI, plus it may have one or several Autonomic Service Agents as part of slice capability exposure. The Autonomic Networking Infrastructure (ASNI) therefore is the foundation for autonomic functions. The current charter of the ANIMA WG includes the specification of the ASNI, using a few autonomic functions as use cases. ASNI would represent a customized and an approach [I-D.ietf-anima-reference-model] for implementing a general purposed ASI. +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + : : Autonomic Slice Function 1 : : : SSA 1 : SSA 1 : SSA 1 : SSA 1 : +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + : : : : +- - - - - - - - - - - - - - + : : : Autonomic Slice Function 2 : : : : ASC 2 : ASC 2 : : : +- - - - - - - - - - - - - - + : : : : +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -+ : Autonomic Slice Networking Infrastructure : +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -+ + + + +-----------------------------------------+ + + | Autonomic Inter-Slice Orchestration | + + +-----------------------------------------+ + + | | | + +----------+ +-----------+ +----------+ |Slice 1 | |Slice 2 | | Slice N | | SEM |-------| SEM |------ ... ---- | SEM | | | | | | | +----------+ +-----------+ +----------+ | | | Galis, et al. Expires September 6 , 2018 [Page 10] INTERNET DRAFT Autonomic Slice Networking March 2018 +-------------------------------------------------------------+ | | | PEC1 PEC2 PECm | | | ... | ... | | | | | Resources / Network Functions / ANI | | | +-------------------------------------------------------------+ | | | | +----------------------+ +------------+ +------------+ +-------+ +---------+ + +-------+ + + +--------+ + | Node1.1 --| Node1.N |------ |Node2.x|-...------ | NodeM.y| + +-------+ +---------+ + +-------+ + + +--------+ + +----------------------+ +------------+ +------------+ Domain 1 Domain 2 Domain M Figure 1: High level view of Autonomic Slice Networking Additionally, at least 2 autonomous functions are envisioned - Autonomous Slice control (ASC) and Slice Service agent (SSA). These are explained in sections below. 4. Autonomic Inter-Slice Orchestration This section describes an autonomic orchestration and its functionality. Orchestration refers to the system functions that: * automated and autonomically co-ordination of network functions in slices * autonomically coordinate the slices lifecycle and all the components that are part of the slice (i.e. Service Instances, Network Slice Instances, Resources, Capabilities exposure) to ensure an optimized allocation of the necessary resources across the network. * coordinate a number of interrelated resources, often distributed across a number of subordinate domains, and to assure transactional integrity as part of the process [TETT1]. * autonomically control of slice life cycle management, including concatenation of slices in each segment of the infrastructure including the data pane, the control plane, and the management plane. Galis, et al. Expires September 6 , 2018 [Page 11] INTERNET DRAFT Autonomic Slice Networking March 2018 * autonomically coordinate and trigger of slice elasticity and placement of logical resources in slices. * coordinates and (re)-configure logical resources in the slice by taking over the control of all the virtualized network functions assigned to the slice. It is also the continuing process of allocating resources to satisfy contending demands in an optimal manner [TETT2]. The idea of optimal would include at least prioritized SLA commitments [SERMODEL], and factors such as customer endpoint location, geographic or topological proximity, delay, aggregate or fine-grained load, monetary cost, fate- sharing or affinity. The word continuing incorporates recognition that the environment and the service demands constantly change over the course of time, so that orchestration is a continuous, multi-dimensional optimization feedback loop [I- D.strassner-anima-control-loops]. It protects the infrastructure from instabilities and side effects due to the presence of many slice components running in parallel. It ensures the proper triggering sequence of slice functionality and their stable operation. It defines conditions/constraints under which service components will be activated, taking into account operator service and network requirements (inclusive of optimize the use of the available network & compute resources and avoid situations that can lead to sub-par performance and even unstable and oscillatory behaviors. 5. GRASP Resource Reservation / Release Messages flow Inter Slice Physical Slice Element Element Domain Physical Orchestrator Manager Manager Manager Function | | | | | | GRASP Discovery |GRASP Discovery|GRASP Discovery |GRASP Discovery| | -Response | -Response | -Response | -Response | | <-------------->| <------------>| <-----------> | <-----------> | | | | | | | GRASP Request | | | | |Slicing Objective | GRASP Request | | | | -------------> | Slicing | | | | | Objectives | GRASP Request | | | | ------------> | Slicing |GRASP Request | | | | Objectives |Slicing | Galis, et al. Expires September 6 , 2018 [Page 12] INTERNET DRAFT Autonomic Slice Networking March 2018 | | | -----------> |Objectives | | | | |-----------> | | | | GRASP | | | | | Confirm-Waiting | | | | | <--------- | | | |GRASP | | | | |Confirm-Waiting| |GRASP | | | <----------- | |Negotiation | | | | |Single/Multiple| | | |GRASP Negotiation|Rounds | | | |Single/Multiple |<-----------> | | | |Rounds | | | GRASP | | <-----------> | | | Confirm-Waiting | | | | |<--------------- |GRASP | | | | |Negotiation | | | | |Single/Multiple| | | | |Rounds | | | |GRASP Negotiation | <-----------> | | | |Single/Multiple | | | | |Rounds | | | | | <------------> | | | | Figure 2 - GRASP: Network Slice reservation / Release3 Messages Flow The above message sequence figure shows the message flows of the interactions between Inter-Slice Orchestrator, Slice Element Manager, Physical Element Manager, Domain Manager and Physical Network functions. 6. The Autonomic Network Slicing Element This section describes an autonomic slice network element and its internal architecture. The reference model explained in the document "Autonomic Networking - Definitions and Design Goals" [RFC7575] shows the sources of information that an autonomic service agent can leverage: Self-management, Self-knowledge, network knowledge (through discovery), Intent [I-D.du-anima-an-intent], and feedback loops. Fundamentally, there are two levels inside an autonomic node: the level of Autonomic Service Agents, and the level of the Autonomic Slice Networking Infrastructure, with the former using the services of the latter. The self management functionality (self-configuration, self-optimisation, self- healing) could be implemented across the Inter Slice Orchestrator, Slice Element Manager and Physical Element Manager. Such functionality deals with dynamic * coordination the life cycle of slices Galis, et al. Expires September 6 , 2018 [Page 13] INTERNET DRAFT Autonomic Slice Networking March 2018 * allocation of resources to slice instances in an efficient way that provides required slice instances performance, * self-configuration, self-optimization and self-healing of slice instances during their lifecycle management including deployment and operations * self-configuration, self-optimization and self-healing of services of each slice instance. Service lifecycle, that is typically different than slice instance lifecycle should also be managed in the autonomous way. Figure 3 illustrates this concept. +------------------------------------------------------------+ | | | +-----------+ +------------+ +------------+ | | | Autonomic | | Autonomic | | Autonomic | | | | Service | | Service | | Service | | | | Agent 1 | | Agent 2 | | Agent 3 | | | +-----------+ +------------+ +------------+ | | ^ ^ ^ | | - - -| - - API level - - | - - - - - - - - - - |- - - - - | | V V V | |------------------------------------------------------------| | Autonomic Slice Networking Infrastructure | | - Service characteristics (ultra-low latency, | | ultra-reliability, etc) | | - Autonomic Control Plane functions | | - Autonomic Management Plane functions | | - Self-x functions and related control loops elements | | - Autonomic Slice Addressing | | Discovery, negotiation and synchronisation functions | | - Intent distribution | | - Aggregated reporting and feedback loops | | - Routing | | - Security mechanisms | |------------------------------------------------------------| | Basic Operating System Functions | +------------------------------------------------------------+ Figure 3: Model of an autonomic element The Autonomic Slice Networking Infrastructure (lower part of Figure 2) contains slice specific data structures, for example trust information about itself and its peers, as well as a generic set of functions, independent of a particular usage. This infrastructure should be generic, and support a variety of Autonomic Service Agents Galis, et al. Expires September 6 , 2018 [Page 14] INTERNET DRAFT Autonomic Slice Networking March 2018 (upper part of Figure 2). The Autonomic Control Plane is the summary of all interactions of the Autonomic Slice Networking Infrastructure with other services. The use cases of "Autonomics" such as self-management, self- optimisation, etc, are implemented as Autonomic Service Agents. They use the services and data structures of the underlying autonomic networking infrastructure. The Autonomic Slice Networking Infrastructure should itself be self-managing. The "Basic Operating System Functions" include the "normal OS", including the network stack, security functions, etc. Autonomic Network Slicing Element is a composition of autonomic slice service agents and autonomic slice control. Autonomic slice service agents obtain specific network resources and provide self-managing and self- controlling functions. An autonomic slice control is a higher-level autonomic function that takes the role of life-cycle management of a or many slice instances. There can be many slice control functions based on different types or attributes of slice. 7. The Autonomic Slice Networking Ianfrastructure The Autonomic Networking Infrastructure provides a layer of common functionality across an Autonomic Network. It comprises "must implement" functions and services, as well as extensions. The Autonomic Slice Networking Infrastructure (ASNI) resides on top of an abstraction layer of resource, network function and network infrastructure as shown in figure 1. The document assumes abstraction layer enables different autonomous service agents to communicate with the underlying disaggregated and distributed network infrastructure, which itself maybe an autonomous networking (AN) domain or combination of multiple AN domain. The goal of ASNI is to provide autonomic life-cycle management of network slices. 7.1. Signaling Between Autonomic Slice Element Managers The basic network capabilities are autonomically or through traditional techniques are learnt by slice agents. This depends on the fact that physical infrastructure is an autonomic network or not. The GASP extensions signaling [I-D.liu-anima-grasp-distribution] [I-D.liu-anima-grasp-api] [I-D.ietf-anima-grasp] may be used for * Discovery of SEMs - a process by which an one SEM discovers peers according to a specific discovery objective. The discovered SEMs peers may later be used as negotiation counterparts or as sources of other coordination activities. Galis, et al. Expires September 6 , 2018 [Page 15] INTERNET DRAFT Autonomic Slice Networking March 2018 * Negotiation between SEMs - a process by which two SEMs interact to agree on slice logical resource settings that best satisfy the objectives of both SEMs. * The Synchronization between SEMs - a process by which Orchestrator and SEMs interact to receive the current state of capability exposure values used at a given time in other SEM. This is a special case of negotiation in which information is sent but the SEM or Orchestrator do not request their peers to change configuration settings. * Self configuration of SEMs - a process by which Orchestrator and SEMs interact to receive the current state of capability exposure values used at a given time in other SEM. This is a special case of synchronization in which information is sent and the SEM is requesting their peers to change configuration settings. * Self optimization of SEMs - a process by which Orchestrator and SEMs interact to receive the current state of capability exposure values used at a given time in other SEMs. This is a special case of configuration in which information is sent and the SEM is requesting their peers to change logical resource settings in a slice based on an optimisation criteria. * Mediation for slice resources - a process by which two SEMs interact to agree to logically move resources between slices that best satisfy the objectives of both SEMs triggering of slice elasticity and placement of logical resources in slices. Th???is is a special case of negotiation in which information is sent Orchestrator do request SEMs to change logical resource configuration settings. * Triggering and governing of elasticity ? a process for autonomic scaling intent configuration mechanisms and resources on the slice level; it allows rapid provisioning, automatic scaling out, or in, of resources. Scale in/out criteria might be used for network autonomics in order the controller to react to a certain set of variations in monitored slices. * Providing on-demand a self-service network slicing. Optionally, SSA capabilities are more interesting to slice control autonomic functions for slice creation and install. The slice control must have the independent intelligence to process and filter capabilities to meet a network slice specification and have low level resources allocated for a slice through SSAs. Galis, et al. Expires September 6 , 2018 [Page 16] INTERNET DRAFT Autonomic Slice Networking March 2018 7.2. The Autonomic Control Plane TBD. 7.3. Naming & Addressing A slice can be instantiated on demand, represents a logical network and therefore, must be assigned a unique identifier. A Slice Service Agent (SSA) may support functions of a single or multiple slices and communicate with each other, using the addressing of the Autonomic or traditional (non-autonomic) Networking Infrastructure reside on. An SSA complies with ACP addressing mechanisms and in a domain, i.e., As part of the enrolment process the registrar assigns a number to the device, which is unique for slicing registrar and in ASNI domain. 7.4. Discovery Slices themselves are not discovered but are instantiated through slice control autonomic function. However, both slice service agents and slice control functions must be discovered. Even though autonomic control plane will support discovery of all the SSAs and slice control, it may not be necessary. 7.5. Routing Autonomic network slicing follows single routing protocol as described in [I-D.ietf-anima-autonomic-control-plane]. 8. Security and Trust Infrastructure An Autonomic Slice Network is self-protecting. All protocols are secure by default, without the requirement for the administrator to explicitly configure security. TBD. 8.1. Public Key Infrastructure An autonomic domain uses a PKI model. The root of trust is a certification authority (CA). A registrar acts as a registration authority (RA). A minimum implementation of an autonomic domain contains one CA, one Registrar, and network elements. 8.2. Domain Certificate Galis, et al. Expires September 6 , 2018 [Page 17] INTERNET DRAFT Autonomic Slice Networking March 2018 TBD. 9. Cross-Domain Functionality TBD. 10. Autonomic Service Agents (ASA) This section describes how autonomic services run on top of the Autonomic Slice Networking Infrastructure. There are at least two different types of autonomic functions are known: 1. Slice Service Agents are low level functions that learn capabilities of underlying infrastructure in terms of interfaces and available resources. They coordinate with Slice control to associate these resources with specific slice instances in effect performing full life cycle management of these resources. 2. Slice Control Autonomic Function: Slice control is responsible for high-level life-cycle management of a slice itself. This function will hold slice instances and their attributes related data structures in autonomic network slice infrastructure. As an example, a slice is defined for high bandwidth, highly secure transactional application. A slice control must be capable of negotiating resources required across different SSAs. Out of scope are details of the mechanisms how the information is represented and exchanged between the two autonomic functions. 11. Management and Programmability This section describes how an Autonomic Network is managed, and programmed. 11.1. How a Slice Network Is Managed Slice autonomic management is driven by Slice Element Managers, there are five categories operation: 1. Creating a network slice: Receive a network slice resource description request, upon successful negotiation with SSA allocate resource for it. 2. Shrink/Expand slice network: Dynamically alter resource requirements for a running slice network according service load. 3. (Re-)Configure slice network: The slice management user deploys a user level service into the slice. The slice control takes over the control of all the virtualized network functions and network programmability functions assigned to the slice, and Galis, et al. Expires September 6 , 2018 [Page 18] INTERNET DRAFT Autonomic Slice Networking March 2018 (re-)configure them as appropriate to provide the end-to-end service. 5. Self-X slice operation: namely self-configuration, self- composition, self-monitoring, self-optimisation, self-elasticity would be carried out as part of new slice protocols. 11.2. Autonomic Resource Information Model TBD. The proposed autonomic resource information model is presented as a tree structure of attributes including the following elements: connectivity resources, storage resources, compute resources, service instances, network slice level attributes, etc. The Yang language would be used to represent the autonomic resource information model. 11.3. Control Loops TBD. 11.4. APIs The API model of for autonomic slicing semantically, is grouped into the following APIs to be defined. 11.4.1. Slice Control APIs 1. Create a slice network on user request. The request includes resource description. A unique identify a slice network, group all the resource. 2. Destroy a slice network identified by it's id. 3. Query a slice network slicing state by it's uuid. 4. Modify a slice network. 11.4.2. Service Agent - Device APIs A service agent will interface with the physical infrastructure either through an autonomic network or traditional infrastructure. Depending upon which a device can either have autonomic or non- autonomic addressing. Service agents are required to perform life cycle management of network elements participating in a network slice and the following APIs are needed for addition, removal or update of a specific device. A device may be a logical or physical network element. Optionally, it may be a network function. 11.4.3. Service Agent - Port APIs Galis, et al. Expires September 6 , 2018 [Page 19] INTERNET DRAFT Autonomic Slice Networking March 2018 A port may be a physical or logical network port in a slice depending upon whether underlying infrastructure is an autonomic or traditional network. Service agents must be able to control the operational state of these ports. APIs are needed for addition, removal, update and operational state retrieval of a specific port. 11.4.4. Service Agent - Link APIs A link connects two or more ports of devices described in above section. Service agents must be able to control the operational and connection status of these links through APIs for addition, removal, update and state retrieval for each link. 11.5. Relationship with MANO Please refer to [MANO] for MANO introduction. 12. Security Considerations 12.1. Threat Analysis TBD. 12.2. Security Mechanisms TBD. 13. IANA Considerations This document requests no action by IANA. 14. Acknowledgements This document was converted to nroff by Stuart Clayman (UCL) to comply with RFC format [RFC2629]. 14. References 14.1. Normative References [I-D.ietf-anima-grasp] Bormann, C., Carpenter, B., and B. Liu, "A Generic Autonomic Signaling Protocol (GRASP)", draft-ietf- anima- grasp-10 (work in progress), March 2017. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . Galis, et al. Expires September 6 , 2018 [Page 20] INTERNET DRAFT Autonomic Slice Networking March 2018 [RFC7665] Halpern, J., Pignataro, C., "Service Function Chaining (SFC) Architecture", October 2015 . [RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629, DOI 10.17487/RFC2629, June 1999, . 14.2. Informative References [ChinaCom09] A. Galis et all - "Management and Service-aware Networking Architectures (MANA) for Future Internet" - Invited paper IEEE 2009 Fourth International Conference on Communications and Networking in China (ChinaCom09) 26-28 August 2009, Xi'an, China, . [GENI] "GENI Key Concepts - Global Environment for Network Innovations (GENI)" . [I-D.du-anima-an-intent] Du, Z., Jiang, S., Nobre, J., Ciavaglia, L., and M. Behringer, "ANIMA Intent Policy and Format", draft- du- anima-an-intent-04 (work in progress), July 2016. [I-D.ietf-anima-autonomic-control-plane] Behringer, M., Eckert, T., and S. Bjarnason, "An Autonomic Control Plane", draft- ietf-anima-autonomic-control- plane-03 (work in progress), July 2016. [I-D.ietf-anima-reference-model] Behringer, M., Carpenter, B., Eckert, T., Ciavaglia, L., Pierre, P., Liu, B., Nobre, J., and J. Strassner, "A Reference Model for Autonomic Networking", draft-ietf- anima-reference-model-02 (work in progress), July 2016. [I-D.liu-anima-grasp-api] Carpenter, B., Liu, B., Wang, W., and X. Gong, "Generic Autonomic Signaling Protocol Application Program Interface (GRASP API)", draft-liu-anima-grasp-api- 02 (work in progress), September 2016. [I-D.liu-anima-grasp-distribution] Liu, B. and S. Jiang, "Information Distribution over GRASP", draft-liu-anima-grasp- distribution-02 (work in progress), September 2016. [I-D.strassner-anima-control-loops] Strassner, J., Halpern, J., and M. Behringer, "The Use of Control Loops in Autonomic Networking", draft-strassner- anima-control-loops-01 (work Galis, et al. Expires September 6 , 2018 [Page 21] INTERNET DRAFT Autonomic Slice Networking March 2018 in progress), April 2016. [IMT2020] ITU-T IMT2020 document "Report on Gap Analysis" - ITU-T IMT2020 ITU- Dec 2015 Published by ITU-T IMT2020. . [MANO] "ETSI European Telecommunications Standards Institute. Network Functions Virtualisation (NFV); Management and Orchestration v1.1.1." Website, December 2014. . [NGMN] Hedmar,P., Mschner, K., et all - NGMN Alliance document "Description of Network Slicing Concept", January 2016. . [NGS-3GPP] "Study on Architecture for Next Generation System" - latest version v1.0.2 September 2016 . [ONF] Paul, M, Schallen, S., Betts, M., Hood, D., Shirazipor, M., Lopes, D., Kaippallimalit, J., - Open Network Fundation document "Applying SDN Architecture to 5G Slicing", April 2016. . [NS1] L. Geng, J. Dong, S. Bryant, K., Makhijani, A., Galis, X. de Foy, S. Kuklinski, - "Network Slicing Architecture", July 2017. . [NS2] L. Geng, L. Wang, S. Kuklinski, L. Qiang, S. Matsushima, A., Galis, L. Contreras - "Problem Statement of Supervised Heterogeneous Network Slicing", October 2017 . [ASN] A., Galis, K., Makhijani, D. Yu, B. Liu - "Autonomic Slice Networking-Requirements and Reference Model" - May 2017 < https://datatracker.ietf.org/doc/draft-galis-anima- autonomic-slice-networking/>. [RFC7575] Behringer, M., Pritikin, M., Bjarnason, S., Clemm, A., Galis, et al. Expires September 6 , 2018 [Page 22] INTERNET DRAFT Autonomic Slice Networking March 2018 Carpenter, B., Jiang, S., and L. Ciavaglia, "Autonomic Networking: Definitions and Design Goals", RFC 7575, DOI 10.17487/RFC7575, June 2015, . [RFC7576] Jiang, S., Carpenter, B., and M. Behringer, "General Gap Analysis for Autonomic Networking", RFC 7576, DOI 10.17487/RFC7576, July 2016, . [TETT1] Guerzoni, R., Vaishnavi, I., Pares-Caparros, D., Galis, A., et al, "Analysis of End-to-End Multi Domain Management and Orchestration Frameworks for Software Defined Infrastructures: an Architectural Survey", Transactions on Emerging Telecommunications Technologies, Wiley Online Library, DOI: 10.1002/ett.3103, June 2016, . [TETT2] Karl, H., Draxler, S., Peuster, M, Galis, A., et all "DevOps for Network Function Virtualization: An Architectural Approach", Transactions on Emerging Telecommunications Technologies Wiley Online Library, DOI: 10.1002/ett.3084, July 2016, . [SERMODEL] C., Borman, B. Carpenter, B., Liu, "Service Models Explained " draft-wu-opsawg-service-model-explained-05 . [5GNS] Galis, A. (UCL), Chih-Lin I (China Mobile) - "Towards 5G Network Slicing - Motivations and Challenges" March 2017, IEEE 5G Tech Focus, Volume 1, Number 1, March 2017- . [PER-NS] Galis, A. - " Perspectives on Network Slicing - Towards the New 'Bread and Butter' of Networking and Servicing", IEEE SDN Initiative - January 2018 . [NS-ETSI] "Network Functions Virtualisation (NFV) Release 3; Evolution and Ecosystem; Report on Network Slicing Support with ETSI NFV Architecture Framework- ETSI GR NFV-EVE 012 V3.1.1 (2017-12)" Authors' Addresses Alex Galis (editor) University College London Department of Electronic and Electrical Engineering Torrington Place London WC1E 7JE United Kingdom Email: a.galis@ucl.ac.uk Kiran Makhijani Huawei Technologies 2890, Central Expressway Santa Clara CA 95032 USA Email: USA Email: kiran.makhijani@huawei.com Delei Yu Huawei Technologies Q22, Huawei Campus No.156 Beiqing Road Hai-Dian District, Beijing 100095 P.R. China Email: yudelei@huawei.com Bing Liu Huawei Technologies Co., Ltd Q14, Huawei Campus No.156 Beiqing Road Hai-Dian District, Beijing 100095 P.R. China Email: leo.liubing@huawei.com Galis, et al. 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