Internet DRAFT - draft-li-teas-e2e-ietf-network-slicing
draft-li-teas-e2e-ietf-network-slicing
Network Working Group Z. Li
Internet-Draft J. Dong
Intended status: Standards Track Huawei Technologies
Expires: 8 September 2022 R. Pang
China Unicom
Y. Zhu
China Telecom
7 March 2022
Framework for End-to-End IETF Network Slicing
draft-li-teas-e2e-ietf-network-slicing-02
Abstract
Network slicing can be used to meet the connectivity and performance
requirement of different services or customers in a shared network.
An IETF network slice may be used for 5G or other network scenarios.
In the context of 5G, the 5G end-to-end network slices consist of
three major types of network technology domains: Radio Access Network
(RAN), Transport Network (TN) and Core Network (CN). The transport
network slice can be realized as IETF network slices. In the
transport network, the IETF network slice may span multiple network
administrative domains.
In order to facilitate the mapping between network slices in
different network technology domains and administrative domains, it
is beneficial to carry the identifiers related to the 5G end-to-end
network slice, the multi-domain IETF network slice together with the
intra-domain network slice related identifier in the data packet.
This document describes the framework of end-to-end IETF network
slicing, and introduces the identifiers related to 5G end-to-end
network slice and the multi-domain IETF network slice. These
identifiers can be carried in the data packet. The roles of the
different identifiers in packet forwarding is also described. The
network slice identifiers may be instantiated with different data
planes.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
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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
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This Internet-Draft will expire on 8 September 2022.
Copyright Notice
Copyright (c) 2022 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 (https://trustee.ietf.org/
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Please review these documents carefully, as they describe your rights
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Framework . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Requirements on E2E IETF Network Slicing . . . . . . . . . . 5
3.1. Data Plane . . . . . . . . . . . . . . . . . . . . . . . 6
3.2. Management Plane/Control Plane . . . . . . . . . . . . . 6
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 6
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Normative References . . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
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1. Introduction
[I-D.ietf-teas-ietf-network-slices] defines the terminologies and the
characteristics of IETF network slices. It also discusses the
general framework, the components and interfaces for requesting and
operating IETF network slices. A Network Resource Partition (NRP) is
a collection of network resources in the underlay network that are
available to carry traffic and meet the SLOs and SLEs.
[I-D.ietf-teas-enhanced-vpn] describes the framework and the
candidate component technologies for providing enhanced VPN (VPN+)
services based on existing VPN and Traffic Engineering (TE)
technologies with enhanced characteristics that specific services
require above traditional VPNs. It also introduces the concept of
Virtual Transport Network (VTN), which is a virtual underlay network
consisting of a set of dedicated or shared network resources
allocated from the physical underlay network, and is associated with
a customized network topology. VPN+ services can be delivered by
mapping one or a group of overlay VPNs to the appropriate VTNs as the
underlay, so as to provide the network characteristics required by
the customers. Enhanced VPN (VPN+) and VTN can be used for the
realization of IETF network slices. In the context of IETF network
slicing, NRP can be seen as an instantiation of VTN.
[I-D.dong-teas-nrp-scalability] describes the scalability
considerations in the control plane and data plane of NRP, and
proposed several suggestions to improve the scalability. In the
control plane, It proposes the approach of decoupling the topology
and resource attributes of NRP, so that multiple NRPs may share the
same topology attributes and the result of topology based path
computation. In the data plane, it proposes to carry a global NRP-ID
of a network domain in the data packet to determine the set of
resources reserved for the corresponding NRP.
An IETF network slice may span multiple network administrative
domains. Further in the context of 5G, there are end-to-end network
slices which consists of three major types of network technology
domains: Radio Access Network (RAN), Transport Network (TN) and Core
Network (CN). In order to facilitate the mapping between network
slices in different network technology domains and administrative
domains, it may be beneficial to carry the identifiers related to the
5G end-to-end network slice, the identifiers of the multi-domain IETF
network slices together with the intra-domain network slices related
identifiers in the data packet.
This document describes the typical scenarios of end-to-end network
slicing, and the framework of concatenating network slices in
different network technology domains and administrative domains.
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Multiple network slice related identifiers are defined for network
slices with different network scopes. These network slice related
identifiers can be instantiated using different data planes, such as
IPv6 and MPLS.
2. Framework
/----\ /----\ /----\ /----\ /----\
/ \ // \\ // \\ // \\ / \
| RAN |---| TN-1 |---| TN-2 |----| TN-3 |----| Core |
\ / \\ // \\ // \\ // \ /
\----/ \----/ \----/ \----/ \----/
5G Network Slice
o--------------------------------------------------------------------o
IETF Network Slice (VPN+)
o--------------------------------------------------o
Global NRP (VTN)
o===========================================o
Local NRP-1 Local NRP-2 Local NRP-3
o************o o************o o***********o
Figure 1. 5G end-to-end network slicing scenario
One typical scenario of 5G end-to-end network slicing is shown in
figure 1. The 5G end-to-end network slice is identified by the
S-NSSAI (Single Network Slice Selection Assistance Information). In
the transport network, the 5G network slice is mapped to an IETF
network slice. In a multi-domain transport network, an IETF network
slice can be realized with a multi-domain VPN+ service. In the
underlay network, the multi-domain VPN+ service can be supported by a
multi-domain VTN, which is the concatenation of multiple intra-domain
NRPs in different domains. In each domain, a domain-significant NRP-
ID can be carried in the packet to identify the set of network
resource reserved for the NRP in the corresponding domain. Note this
is similar to the Option C mode of inter-domain VPN service
[RFC4364]. Using Option A or Option B mode of inter-domain VPN for
5G end-to-end network slicing is also possible, which is out of the
scope of the current version of this document.
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In order to concatenate multiple domain-wide NRPs into a multi-domain
NRP, the global NRP-ID can be carried in the packet, which is used by
the domain border nodes to map to the local NRP-IDs in each domain.
And in order to facilitate the network slice mapping between RAN,
Core network and transport network, the S-NSSAI may be carried in the
packet sent to the transport network, which can be used by the
transport network to map the 5G end-to-end network slice to the
corresponding IETF network slice.
According to the above end-to-end network slicing scenario, there can
be three network slice related identifiers in the data packet:
* Domain NRP-ID: This is the NRP-ID as defined in
[I-D.dong-teas-nrp-scalability]. It is used by the network nodes
in a network domain to determine the set of local network
resources reserved for an NRP. It SHOULD be processed by each hop
along the path in the domain.
* End-to-end NRP-ID: This is the identifier which uniquely
identifies a multi-domain NRP. In each network domain, the domain
border nodes map the global NRP-ID to the domain NRP-ID for packet
forwarding.
* 5G end-to-end network slice ID (S-NSSAI): This is the identifier
of the 5G end-to-end network slice. When required, it may be used
by the network nodes to provide traffic monitoring at the end-to-
end network slice granularity.
For the above network slice identifiers, the domain NRP-ID is
mandatory, the global NRP-ID and the 5G S-NSSAI are optional. The
existence of the Global NRP-ID depends on whether the NRP spans
multiple network domains in the transport network, and how the domain
NRP-IDs are managed. In some network scenarios, different network
domains can have consistent NRP ID allocation, then the domain NRP-ID
can has the same value as a global NRP-ID. The existence of the 5G
S-NSSAI depends on whether an IETF network slice is used as part of
the 5G end-to-end network slice.
3. Requirements on E2E IETF Network Slicing
This section lists the requirements on E2E IETF network slicing.
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3.1. Data Plane
To facilitate the mapping between 5G end-to-end network slice and
IETF network slice, and the mapping between multi-domain IETF network
slice and the intra-domain IETF network slice, different network
slice related identifiers, including the S-NSSAI, the Global NRP-ID,
domain NRP-ID need to be carried in the data packet.
In a multi-domain IETF network slice, the domain border nodes should
support to map the Global NRP-ID to the domain NRP-ID of the local
domain. In a 5G end-to-end network slicing scenario, the edge nodes
of IETF network slice should support to map the S-NSSAI to the global
NRP-ID and the domain NRP-ID. When the correlation between S-NSSAI
and the NRP-ID needs to be maintained, the edge nodes of IETF network
slices should be able to derive the S-NSSAI from the data packet
received from RAN and CN, and encapsulate both the S-NSSAI and the
NRP-ID into an outer packet header when traversing the transport
network domains.
3.2. Management Plane/Control Plane
For multi-domain IETF network slice, a centralized IETF network slice
controller is responsible for the allocation of the Global NRP-ID and
the domain NRP-IDs, and the provisioning of the mapping relationship
between the Global NRP-ID and the domain NRP-IDs to the border nodes
in different network domains.
For 5G end-to-end network slice, when S-NSSAI is used for the mapping
from RAN or CN network slices to IETF network slices, the IETF
network slice controller is responsible for the provisioning of the
mapping relationship between S-NSSAI and the Global and local NRP-IDs
at the edge nodes of IETF network slices.
4. IANA Considerations
This document makes no request of IANA.
Note to RFC Editor: this section may be removed on publication as an
RFC.
5. Security Considerations
TBD
6. Acknowledgements
TBD
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7. References
7.1. Normative References
[I-D.ietf-teas-enhanced-vpn]
Dong, J., Bryant, S., Li, Z., Miyasaka, T., and Y. Lee, "A
Framework for Enhanced Virtual Private Network (VPN+)
Services", Work in Progress, Internet-Draft, draft-ietf-
teas-enhanced-vpn-09, 25 October 2021,
<https://www.ietf.org/archive/id/draft-ietf-teas-enhanced-
vpn-09.txt>.
[I-D.ietf-teas-ietf-network-slices]
Farrel, A., Drake, J., Rokui, R., Homma, S., Makhijani,
K., Contreras, L. M., and J. Tantsura, "Framework for IETF
Network Slices", Work in Progress, Internet-Draft, draft-
ietf-teas-ietf-network-slices-08, 6 March 2022,
<https://www.ietf.org/archive/id/draft-ietf-teas-ietf-
network-slices-08.txt>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
7.2. Informative References
[I-D.dong-teas-nrp-scalability]
Dong, J., Li, Z., Gong, L., Yang, G., Guichard, J. N.,
Mishra, G., Qin, F., Saad, T., and V. P. Beeram,
"Scalability Considerations for Network Resource
Partition", Work in Progress, Internet-Draft, draft-dong-
teas-nrp-scalability-01, 7 February 2022,
<https://www.ietf.org/archive/id/draft-dong-teas-nrp-
scalability-01.txt>.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
2006, <https://www.rfc-editor.org/info/rfc4364>.
Authors' Addresses
Zhenbin Li
Huawei Technologies
Huawei Campus, No. 156 Beiqing Road
Beijing
100095
China
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Email: lizhenbin@huawei.com
Jie Dong
Huawei Technologies
Huawei Campus, No. 156 Beiqing Road
Beijing
100095
China
Email: jie.dong@huawei.com
Ran Pang
China Unicom
Email: pangran@chinaunicom.cn
Yongqing Zhu
China Telecom
Email: zhuyq8@chinatelecom.cn
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