TEAS LM. Contreras
Internet-Draft Telefonica
Intended status: Informational R. Rokui
Expires: May 6, 2021 Nokia
J. Tantsura
Apstra
B. Wu
Huawei
X. Liu
Volta
D. Dhody
Huawei
S. Belloti
Nokia
November 2, 2020
IETF Network Slice Controller and its associated data models
draft-contreras-teas-slice-controller-models-00
Abstract
This document describes the major functional components of an IETF
Network Slice Controller (NSC) as well as references the data models
required for supporting the requests of IETF network slices and their
realization.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on May 6, 2021.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. IETF Network Slice data models . . . . . . . . . . . . . . . 3
3. Structure of the IETF Network Slice Controller (NSC) . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
Editor's Note: the terminology in this draft will be aligned with the
final terminology selected for describing the notion of IETF Network
Slice when applied to IETF technologies, which is currently under
discussion. By now same terminology as used in
[I-D.nsdt-teas-ietf-network-slice-definition] and
[I-D.nsdt-teas-ns-framework] is primarily used here. Consensus to
use "IETF Network Slice" term has been reached.
The generic idea of network slicing intends to provide tailored end-
to-end network capabilities to customers in the way that they could
be perceived as a dedicated network, despite the fact that it makes
use of shared physical infrastructure facilities.
Among the capabilities mentioned, connectivity of different parts of
a network slice with particular characteristics play a central role.
Thus, the concept of IETF Network Slice, realized by any of the IETF
technologies, emerges as complementary but essential part of an end-
to-end network slice.
In order to facilitate the request, realization and lifecycle control
and management of a transport slice, a new element named IETF Network
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Slice Controller (NSC) is being proposed in
[I-D.nsdt-teas-ietf-network-slice-definition] and
[I-D.nsdt-teas-ns-framework].
The NSC from its North Bound Interface (NBI) exposes set of APIs that
allow a higher level system to request an end-to-end transport slice.
It receives the request of enablement of an IETF Network Slice by a
customer (i.e. creation, modification or deletion). Upon receiving a
request from its NBI, NSC finds the resources needed for realization
of the IETF Network Slice and in turn interfaces from its South Bound
Interface (SBI) with one or more Network Controllers for the
realization of the requested IETF Network Slice request and the
management of its lifecycle. Figure 1 presents a high-level view of
the TSC.
+------------------------------------------+
| A higher level system |
| (e.g E2E network slice orchestrator) |
+------------------------------------------+
A
| NSC NBI
V
+------------------------------------------+
| IETF Network Slice Controller (NSC) |
+------------------------------------------+
A
| NSC SBI
V
+------------------------------------------+
| Network Controller(s) |
+------------------------------------------+
Figure 1: Interface of Transport Slice Controller
This memo describes the characteristics of the NSC as well as a
detailed structure of the NSC and its major components. In addition,
it describes the characteristics of the data models to identify the
IETF Network Slice and its realization. Then the data models
referred are mapped to the interfaces among components.
2. IETF Network Slice data models
At the time of provisioning and operating IETF Network Slices
different views can be identified as necessary:
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o Customer's view, mostly focused on the individual IETF Network
Slice request process, reflecting the needs of each particular
customer, including SLOs and other characteristics of the slice
relevant for it. This view is technology agnostics and describes
the characteristics of the IETF Network Slice from a customer's
point of view. It can include the slice topology, performance
parameters, endpoints of the slice, traffic characteristics of the
slice, and the KPIs to monitor the slice.
o Provider's view, mostly focused on the provisioning and operation
of the IETF Network Slices in the transport network, considering
how a particular IETF Network Slice interplays with other IETF
Network Slices maintained by the provider on a shared
infrastructure. In other words, operator's view shows how an IETF
Network Slice is realized in operator's network along with all the
resources used during the its realization.
Both views are complementary, each of them specialized for a given
purpose. In consequence, it should be consistency between both in
order to ensure alignment.
Currently there are two different models proposed, on for each of the
categories above. The model in
[I-D.wd-teas-ietf-network-slice-nbi-yang] fits into the customer
view, while the model defined in
[I-D.liu-teas-transport-network-slice-yang] fits in to the provider
view.
It should be noted that for the realization of a transport slice, the
NSC interacts with one or more Network Controllers. In that case,
the data models to be used are particular for each Network Controller
(e.g., technology dependent), as well as the mapping function from
its NBI to SBI and the details of this mapping function are both out
of the scope of this document.
3. Structure of the IETF Network Slice Controller (NSC)
The NSC should work with both data models. The NSC takes first the
customer's view by analyzing the needs of the customer, processing
such requests taking into account the overall view of the network and
the IETF Network Slices already instantiated, normalizing its
instantiation across different technologies, and finally generates
the provider view.
Once the new request is processed and declared as feasible, the NSC
triggers its realization by interacting with the Network Controllers
and communicates back to the higher level controller to start the
billing cycle.
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In order to accommodate these procedures, the internal structure of
the NSC can be divided into:
o IETF Network Slice Mapper: this high-level component processes the
customer request, putting it into the context of the overall IETF
Network Slices in the network.
o IETF Network Slice Realizer: this high-level component processes
the complete view of transport slices including the one requested
by the customer, decides the proper technologies for realizing the
IETF Network Slice and triggers its realization.
Figure 2 illustrates the components described and the associated
models, as follows
o (a) -> customer's view, e.g.
[I-D.wd-teas-ietf-network-slice-nbi-yang].
o (b) -> provider's view, e.g.
[I-D.liu-teas-transport-network-slice-yang].
o (c) -> models per network controller, out of scope of this
document
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Higher Level System
|
|
---------------------------
| NSC | (a) |
| v |
| ------------------- |
| | | |
| | NS Mapper | |
| | | |
| ------------------- |
| | (b) |
| v |
| ------------------- |
| | | |
| | NS Realizer | |
| | | |
| ------------------- |
| | (c) |
---------------------------
|
v
Network Controllers
Figure 2: IETF Network Slice Controller structure and asspociated
data models
TODO item #1 - Breakdown "NS mapper" and "NS Realizer" to their
logical components.
TODO item #2- Add complementarity of the models for satisfying Type 1
and Type 2 Services as per [RFC8453]. Discussion: equivalent to the
Virtual Network (VN) described in [RFC8453], there are two views of
an IETF network slices as well:
o The IETF network slice can be abstracted as a set of edge-to-edge
links (Type 1).
o The IETF network slice can be abstracted as a topology of virtual
nodes and virtual links (Type 2) which represent the partitioning
of underlay network resources for use by network slice
connectivity.
The use cases of these two types of networks are further described by
[RFC8453]. [I-D.wd-teas-ietf-network-slice-nbi-yang] models the Type
1 service, while [I-D.liu-teas-transport-network-slice-yang] models
the Type 2 service. When a customer intends to request a Type 2
service, [I-D.liu-teas-transport-network-slice-yang] can also be used
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at the point (a) in Figure 2. As an example, when ACTN is used to
realize an IETF network slice, model mappings are described in more
details in [I-D.ietf-teas-actn-yang].
4. Security Considerations
To be done.
5. IANA Considerations
This draft does not include any IANA considerations
6. References
[I-D.ietf-teas-actn-yang]
Lee, Y., Zheng, H., Ceccarelli, D., Yoon, B., Dios, O.,
Shin, J., and S. Belotti, "Applicability of YANG models
for Abstraction and Control of Traffic Engineered
Networks", draft-ietf-teas-actn-yang-06 (work in
progress), August 2020.
[I-D.liu-teas-transport-network-slice-yang]
Liu, X., Tantsura, J., Bryskin, I., Contreras, L., WU, Q.,
Belotti, S., and R. Rokui, "Transport Network Slice YANG
Data Model", draft-liu-teas-transport-network-slice-
yang-01 (work in progress), July 2020.
[I-D.nsdt-teas-ietf-network-slice-definition]
Rokui, R., Homma, S., Makhijani, K., Contreras, L., and J.
Tantsura, "Definition of IETF Network Slices", draft-nsdt-
teas-ietf-network-slice-definition-00 (work in progress),
October 2020.
[I-D.nsdt-teas-ns-framework]
Gray, E. and J. Drake, "Framework for Transport Network
Slices", draft-nsdt-teas-ns-framework-04 (work in
progress), July 2020.
[I-D.wd-teas-ietf-network-slice-nbi-yang]
Bo, W., Dhody, D., Han, L., and R. Rokui, "A Yang Data
Model for IETF Network Slice NBI", draft-wd-teas-ietf-
network-slice-nbi-yang-00 (work in progress), October
2020.
[RFC8453] Ceccarelli, D., Ed. and Y. Lee, Ed., "Framework for
Abstraction and Control of TE Networks (ACTN)", RFC 8453,
DOI 10.17487/RFC8453, August 2018,
<https://www.rfc-editor.org/info/rfc8453>.
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Authors' Addresses
Luis M. Contreras
Telefonica
Ronda de la Comunicacion, s/n
Sur-3 building, 3rd floor
Madrid 28050
Spain
Email: luismiguel.contrerasmurillo@telefonica.com
URI: http://lmcontreras.com/
Reza Rokui
Nokia
Canada
Email: reza.rokui@nokia.com
Jeff Tantsura
Apstra
USA
Email: jefftant.ietf@gmail.com
Bo Wu
Huawei Technologies
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: lana.wubo@huawei.com
Xufeng Liu
Volta Networks
Email: xufeng.liu.ietf@gmail.com
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Dhruv Dhody
Huawei Technologies
Divyashree Techno Park
Bangalore, Karnataka 560066
India
Email: dhruv.ietf@gmail.com
Sergio Belloti
Nokia
Email: sergio.belotti@nokia.com
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