CCAMP Working Group Haomian Zheng
Internet Draft Italo Busi
Intended status: Standard Track Huawei Technologies
Aihua Guo
Futurewei Technologies
Expires: May 2021 November 2, 2020
Framework and Data Model for OTN Network Slicing
draft-zheng-ccamp-yang-otn-slicing-00
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Abstract
The requirement of slicing network resource with desired quality of
service is emerging at every network technology, including the
Optical Transport Networks (OTN). As a part of the transport network,
the OTN has the capability to provide hard pipes with guaranteed data
isolation and deterministic low latency, which are highly demanded in
the Service Level Agreement (SLA).
This document describes a framework for OTN network slicing. A YANG
data model augmentation will be defined in a future version of this
draft.
Table of Contents
1. Introduction...................................................2
2. Use Cases for OTN Network Slicing..............................3
2.1. Leased Line Services with OTN.............................3
2.2. Co-construction and Sharing...............................3
2.3. Wholesale of optical resources............................4
2.4. Vertical dedicated network with OTN.......................4
3. Framework for OTN slicing......................................5
4. YANG Model.....................................................7
5. YANG Tree......................................................7
6. Manageability Considerations...................................7
7. Security Considerations........................................7
8. IANA Considerations............................................7
9. References.....................................................7
9.1. Normative References......................................7
9.2. Informative References....................................8
Acknowledgments...................................................8
Contributors' Addresses...........................................9
Authors' Addresses................................................9
1. Introduction
The requirement of slicing network resource with desired quality of
service is emerging at every network technology, including the
Optical Transport Networks (OTN). As a part of the transport network,
the OTN has the capability to provide hard pipes with guaranteed data
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isolation and deterministic low latency, which are highly demanded in
the Service Level Agreement (SLA).
This document describes a framework for OTN network slicing. A YANG
data model augmentation will be defined in a future version of this
draft.
2. Use Cases for OTN Network Slicing
2.1. Leased Line Services with OTN
For large OTT enterprises, leased lines have the advantage of
providing high-speed connections with low costs. On the other hand,
the traffic control of leased lines is very challenging due to rapid
changes of service demands. Carriers are recommended to provide
network-level slicing capabilities to meet this demand. Based on such
capabilities, private network users have full control over the sliced
resources which have allocated to them and which could be used to
support their leased lines, when needed. Users may formulate policies
based on the demand on services and time to flexibly schedule the
network from the perspective of the entire network. For example, the
bandwidth between any two points may be established or released based
on the time or monitored traffic characteristics, the routing and
bandwidth may be adjusted at specific time interval to maximize
network resource utilization efficiency.
2.2. Co-construction and Sharing
Co-construction and sharing of a network is becoming a popular mean
amongst service providers with the goal of reducing networking
building capex. For Co-construction and sharing case, there are
typically multiple co-founders for the same network. For example, one
founder may provide optical fibres and another founder may provide
OTN equipment, while each of them occupies a certain percentage of
the usage rights of the network resources. In this scenario, the
network O&M is performed by certain founder in each region, where an
independent management and control system is usually deployed by the
same founder. The other founders of the network use each other's
management and control system to provision services remotely. In this
scenario, network resources used by different founders need to be
automatically (associated) divided, isolated, and visualized. In
addition, all founders have independent O&M capabilities, and should
be able to perform service-level provisioning in their respective
slices.
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2.3. Wholesale of optical resources
In the optical resource wholesale market, smaller, local carriers and
wireless carriers may rent resources from larger carriers, or
infrastructure carriers, instead of building their own networks.
Likewise, international carriers may rent resources from respective
local carriers and local carriers may lease their owned networks to
each other to achieve better network utilization efficiency.
From the perspective of a resource provider, it is crucial that a
network slice is timely configured to meet traffic matrix
requirements requested by its tenants. The support for multi-tenancy
within the resource provider's network demands that the network
slices are qualitatively isolated from each other to meet the
requirements for transparency, non-interference, and security.
Typically, a resource purchaser expects to flexibly use the leased
network resources just like they are self-constructed. Therefore,
the purchaser is not only provided with a network slice, but also the
full set of functionalities for operating and maintaining the network
slice. The purchaser also expects to, in a flexible and independent
manner, schedule and maintain physical resources to support their own
end-to-end automation using both leased and self-constructed network
resources.
2.4. Vertical dedicated network with OTN
Vertical industry slicing is an emerging category of network slicing
due to the high demand of private high-speed network interconnects
for industrial applications.
In this scenario, the biggest challenge is to implement
differentiated optical network slices based on the requirements from
different industries. For example, in the financial industry, to
support high-frequency transactions, the slice must ensure to provide
the minimum latency along with the mechanism for latency management.
For the healthcare industry, online diagnosis network and software
capabilities to ensure the delivery of HD video without frame loss.
For bulk data migration in data centers, network needs to support on-
demand, large-bandwidth allocation. In each of the aforementioned
vertical industry scenarios, the bandwidth shall be adjusted as
required to ensure flexible and efficient network resource usage.
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3. Framework for OTN slicing
An OTN slice is a collection of OTN network resources that is used to
establish a logically dedicated OTN virtual network over one or more
OTN networks. For example, the bandwidth of an OTN slice is described
in terms of the number/type of OTN time slots; the labels may be
specified as OTN tributary slots and/or tributary ports to allow
slice users to interconnect devices with matching specifications.
The relationship between an OTN slice and an IETF network slice [I-D.
teas-transport-network-slice-yang] is for further discussions.
To support the configuration of OTN slices, an OTN slice controller
(OTN-SC) can be deployed either outside or within the SDN controller.
In the former case, the OTN-SC translates an OTN slice configuration
request into a TE topology configuration or a set of TE tunnel
configurations, and instantiate it by using the TE topology [RFC8795]
or TE tunnel [I-D.ietf-teas-yang-te] interfaces at the MPI, as
defined in the ACTN framework [RFC8453].
In the latter case, an Orchestrator or an end-to-end slice controller
may request OTN slices directly through the OTN slicing interface
provided by the OTN-SC. A higher-level OTN-SC may also designate the
creation of OTN slices to a lower-level OTN-SC in a recursive manner.
Figure 1 illustrates the OTN slicing control hierarchy and the
positioning of the OTN slicing interfaces.
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+--------------------+
| Provider's User |
+--------|-----------+
|CMI
+----------------------+---------------------------+
| Orchestrator / E2E Slice Controller |
+-----------+------------------------------+-------+
|OTN-SC NBI |
| |
+-----------+---------+ OTN-SC NBI |OTN-SC NBI
| OTN-SC +---------------+ |
+-----------+---------+ | |
|MPI | |
+------------|-------------------------|----|--------+
| SDN | +-------+----+-------+|
| Controller | | OTN-SC ||
| | +-------+------------+|
| | |Internal API |
|+-----------+-------------------------+------------+|
|| PNC/MDSC ||
|+-----------------------+--------------------------+|
+------------------------|---------------------------+
|SBI
+-----------+----------+
|OTN Physical Network |
+----------------------+
Figure 1 - Positioning of OTN Slicing Interfaces
A particular OTN network resource, such as a port or link, may be
sliced in two modes:
o Link-based slicing, where a link and its associated link
termination points (LTPs) are dedicatedly allocated to a
particular OTN network slice.
o Tributary-slot based slicing, where multiple OTN network slices
share the same link by allocating different OTN tributary slots in
different granularities.
Additionally, since OTN tributary slots are usually switched
unconstrained at every node within an OTN network, it is unimportant
to which exact tributary slot(s) an OTN slice is allocated, but
rather mattered is the number and type of the tributary slots.
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4. YANG Model
TBD. The OTN slice YANG model may augment the IETF network slice YANG
models, developed in [I-D. teas-transport-network-slice-yang], and/or
the TE topology defined in [RFC8795].
5. YANG Tree
TBD.
6. Manageability Considerations
To ensure the security and controllability of physical resource
isolation, slice-based independent operation and management are
required to achieve management isolation.
Each optical slice typically requires dedicated accounts,
permissions, and resources for independent access and O&M. This
mechanism is to guarantee the information isolation among slice
tenants and to avoid resource conflicts. The access to slice
management functions will only be permitted after successful security
checks.
7. Security Considerations
<Add any security considerations>
8. IANA Considerations
<Add any IANA considerations>
9. References
9.1. Normative References
[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>.
[RFC8795] Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and
O. Gonzalez de Dios, "YANG Data Model for Traffic
Engineering (TE) Topologies", RFC 8795, DOI
10.17487/RFC8795, August 2020, <https://www.rfc-
editor.org/info/rfc8795>.
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[I-D. teas-transport-network-slice-yang] Liu, X., Tantsura J.,
Bryskin I., Contreras L., Wu Q., Belotti S., and Rokui R.,
"Transport Network Slice YANG Data Model", draft-liu-teas-
transport-network-slice-yang-01 (work in progress), July
2020.
[I-D.ietf-teas-yang-te] Saad, T., Gandhi, R., Liu, X., Beeram, V.,
and I. Bryskin, "A YANG Data Model for Traffic Engineering
Tunnels and Interfaces", draft-ietf-teas-yang-te-22 (work
in progress), November 2019.
9.2. Informative References
TBD
Acknowledgments
This document was prepared using 2-Word-v2.0.template.dot.
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Contributors' Addresses
Henry Yu
Huawei Technologies Canada
Email: henry.yu@huawei.com
Authors' Addresses
Haomian Zheng
Huawei Technologies
H1, Xiliu Beipo Village, Songshan Lake,
Dongguan,
China
Email: zhenghaomian@huawei.com
Italo Busi
Huawei Technologies
Email: italo.busi@huawei.com
Aihua Guo
Futurewei Technologies
Email: aihuaguo.ietf@gmail.com
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