No Working Group A. Galis
Internet-Draft University College London
Intended Status: Standards Track K. Makhijani
Expires: March 30, 2019 D. Yu
B. Liu
Huawei Technologies
September 26, 2018
Autonomic Slice Networking
draft-galis-anima-autonomic-slice-networking-05
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.
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Copyright Notice
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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
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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
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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
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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.
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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
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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.
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(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)
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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.
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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 |
| | | | | |
+----------+ +-----------+ +----------+
| | |
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+-------------------------------------------------------------+
| |
| 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.
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* 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 |
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| | | -----------> |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
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* 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
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(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.
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* 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.
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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
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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
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(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
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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, <http://www.rfc-
editor.org/info/rfc2119>.
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[RFC7665] Halpern, J., Pignataro, C., "Service Function Chaining
(SFC) Architecture", October 2015
<https://tools.ietf.org/html/rfc7665>.
[RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629, DOI
10.17487/RFC2629, June 1999, <http://www.rfc-
editor.org/info/rfc2629>.
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,
<http://www.chinacom.org/2009/index.html>.
[GENI] "GENI Key Concepts - Global Environment for Network
Innovations (GENI)"
<http://groups.geni.net/geni/wiki/GENIConcepts>.
[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
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INTERNET DRAFT Autonomic Slice Networking September 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.
<http://www.itu.int/en/ITU-T/focusgroups/imt-2020/Pages/
default.aspx>.
[MANO] "ETSI European Telecommunications Standards Institute.
Network Functions Virtualisation (NFV); Management and
Orchestration v1.1.1." Website, December 2014.
<http://www.etsi.org/deliver/etsi_gs/NFV-
MAN/001_099/001/01.01.01_60/gs_ nfv-man001v010101p.pdf>.
[NGMN] Hedmar,P., Mschner, K., et all - NGMN Alliance document
"Description of Network Slicing Concept", January 2016.
<https://www.ngmn.org/uploads/
media/160113_Network_Slicing_v1_0.pdf>.
[NGS-3GPP] "Study on Architecture for Next Generation System" -
latest version v1.0.2 September 2016
<http://www.3gpp.org/ftp/tsg_sa/WG2_Arch/Latest_SA2_Specs/
Latest_draft_S2_Specs>.
[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.
<https://www.opennetworking.org/images/stories/downloads/
sdn-resources/technical-reports/
Applying_SDN_Architecture_to_5G_Slicing_TR-526.pdf>.
[NS1] L. Geng, J. Dong, S. Bryant, K., Makhijani, A., Galis, X.
de Foy, S. Kuklinski, - "Network Slicing Architecture",
July 2017. <https://tools.ietf.org/html/draft-geng-
netslices- architecture-02>.
[NS2] L. Geng, L. Wang, S. Kuklinski, L. Qiang, S. Matsushima,
A., Galis, L. Contreras - "Problem Statement of Supervised
Heterogeneous Network Slicing", October 2017
<https://datatracker.ietf.org/doc/draft-geng-coms-problem-
statement/>.
[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.,
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Carpenter, B., Jiang, S., and L. Ciavaglia, "Autonomic
Networking: Definitions and Design Goals", RFC 7575, DOI
10.17487/RFC7575, June 2015, <http://www.rfc-
editor.org/info/rfc7575>.
[RFC7576] Jiang, S., Carpenter, B., and M. Behringer, "General Gap
Analysis for Autonomic Networking", RFC 7576, DOI
10.17487/RFC7576, July 2016, <http://www.rfc-
editor.org/info/rfc7576>.
[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,
<onlinelibrary.wiley.com/doi/10.1002/ett.3103/pdf>.
[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,
<http://onlinelibrary.wiley.com/doi/10.1002/ett.3084/full>.
[SERMODEL] C., Borman, B. Carpenter, B., Liu, "Service Models
Explained " draft-wu-opsawg-service-model-explained-05
<https://datatracker.ietf.org/doc/draft-wu-opsawg-service-
model- explained/>.
[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-
<http://5g.ieee.org/tech-focus/march-2017#networkslicing>.
[PER-NS] Galis, A. - " Perspectives on Network Slicing - Towards the
New 'Bread and Butter' of Networking and Servicing", IEEE
SDN Initiative - January 2018
<https://sdn.ieee.org/newsletter/january-
2018/perspectives-on- network-slicing-towards-the-new-
bread-and-butter-of-networking-and-servicing>.
[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)"
<http://www.etsi.org/deliver/etsi_gr/NFV-
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EVE/001_099/012/03.01.01_60/gr_NFV-EVE012v030101p.pdf>
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
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