Internet DRAFT - draft-li-mpls-e2e-ietf-network-slicing
draft-li-mpls-e2e-ietf-network-slicing
Network Working Group Z. Li
Internet-Draft J. Dong
Intended status: Standards Track Huawei Technologies
Expires: October 16, 2021 April 14, 2021
Encapsulation of End-to-End IETF Network Slice Information in MPLS
draft-li-mpls-e2e-ietf-network-slicing-00
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 span multiple network domains. And in the
context of 5G, the 5G end-to-end network slices consist of three
major types of network segments: Radio Access Network (RAN),
Transport Network (TN) and Core Network (CN).
In order to facilitate the mapping between network slices in
different network segments and network domains, it is beneficial to
carry the identifiers of the 5G end-to-end network slice, the multi-
domain IETF network slice together with the intra-domain network
slice identifier in the data packet.
This document defines the mechanism of encapsulating the end-to-end
network slice related identifiers in MPLS data plane.
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].
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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Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
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This Internet-Draft will expire on October 16, 2021.
Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Extensions to MPLS VTN Extension Header . . . . . . . . . . . 3
2.1. Global VTN-ID Option . . . . . . . . . . . . . . . . . . 4
2.2. 5G Network Slice ID Option . . . . . . . . . . . . . . . 5
3. Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 6
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
7.1. Normative References . . . . . . . . . . . . . . . . . . 6
7.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
The definition and the characteristics of IETF are introduced in
[I-D.ietf-teas-ietf-network-slice-definition], and
[I-D.ietf-teas-ietf-network-slice-framework] describes a general
framework of IETF network slice.
[I-D.ietf-teas-enhanced-vpn] describes the framework and the
candidate component technologies for providing enhanced VPN services.
VPN+ can be built from a VPN overlay and an underlying Virtual
Transport Network (VTN), which has a customized network topology and
a set of dedicated or shared resources in the underlay network.
Enhanced VPN (VPN+) can be used for the realization of IETF network
slices.
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[I-D.dong-teas-enhanced-vpn-vtn-scalability] describes the
scalability considerations in the control plane and data plane to
enable VPN+ services, and provide several suggestions to improve the
scalability of VTN. In the control plane, It proposes the approach
of decoupling the topology and resource attributes of VTN, so that
multiple VTNs may share the same topology and the result of topology
based path computation. In the data plane, it proposes to carry a
VTN-ID in the data packet to determine the set of resources reserved
for the corresponding VTN.
An IETF network slice may span multiple network domains. Further in
the context of 5G, there can be end-to-end network slices which
consists of three major types of network segments: Radio Access
Network (RAN), Transport Network (TN) and Core Network (CN). In
order to facilitate the mapping between network slices in different
network segments and network domains, it may be beneficial to carry
the identifiers of the 5G end-to-end network slice and the multi-
domain IETF network slice together with the intra-domain network
slice identifier in the data packet.
[I-D.li-teas-e2e-ietf-network-slicing] describes the framework of
carrying end-to-end network slice related identifiers in the data
plane, each of the identifiers may span a different network scope.
With MPLS data plane, [I-D.li-mpls-enhanced-vpn-vtn-id] specifies the
extensions and mechanisms to carry the VTN-ID of a single network
domain in an MPLS extension header, so as to improve the scalability
of VTN [I-D.dong-teas-enhanced-vpn-vtn-scalability]. This document
further specifies the extensions and mechanisms of encapsulating the
identifiers of the 5G end-to-end network slice and the multi-domain
IETF network slice in MPLS data plane to support the end-to-end
network slicing.
2. Extensions to MPLS VTN Extension Header
This section describes the approach of encapsulating the end-to-end
network slice identifiers in MPLS data plane. Two new options are
defined in the MPLS VTN extension header as defined in
[I-D.li-mpls-enhanced-vpn-vtn-id].
The format of the VTN extension header is shown as below:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Nibble | Length| Flags | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Options ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1. The format of VTN extension header
The Global VTN-ID and the 5G network slice identifier (i.e. S-NSSAI)
are defined as two new options of the VTN extension header.
Depending on whether a IETF network slice spans multiple domains and
whether it is used as part of the 5G end-to-end network slice, the
Global VTN-ID and the 5G network slice ID are optional in the data
packet.
2.1. Global VTN-ID Option
The format of the Global VTN-ID option is shown as below:
Option Option Option
Type Data Len Data
+--------+--------+--------+--------+--------+--------+
|BBCTTTTT|00000100| Global VTN-ID |
+--------+--------+--------+--------+--------+--------+
Figure 2. The format of Global VTN-ID Option
Option Type: 8-bit identifier of the type of option. The type of
Global VTN-ID option is to be assigned by IANA. The highest-order
bits of the type field are defined as below:
o BB 00 The highest-order 2 bits are set to 00 to indicate that a
node which does not recognize this type will skip over it and
continue processing the header.
o C 0 The third highest-order bit are set to 0 to indicate this
option does not change en route.
Opt Data Len: 8-bit unsigned integer indicates the length of the
option Data field of this option, in octets. The value of Opt Data
Len of the Global VTN-ID option SHOULD be set to 4.
Option Data: 4-octet identifier which uniquely identifies a global
VTN which spans multiple network domains.
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2.2. 5G Network Slice ID Option
The format of the 5G network slice ID option is shown as below:
Option Option Option
Type Data Len Data
+--------+--------+--------+--------+--------+--------+
|BBCTTTTT|00000100| S-NSSAI |
+--------+--------+--------+--------+--------+--------+
Figure 3. The format of 5G network slice ID Option
Option Type: 8-bit identifier of the type of option. The type of 5G
network slice ID option is to be assigned by IANA. The highest-order
bits of the type field are defined as below:
o BB 00 The highest-order 2 bits are set to 00 to indicate that a
node which does not recognize this type will skip over it and
continue processing the header.
o C 0 The third highest-order bit are set to 0 to indicate this
option does not change en route.
Opt Data Len: 8-bit unsigned integer indicates the length of the
option Data field of this option, in octets. The value of Opt Data
Len of the 5G network slice ID option SHOULD be set to 4. This
aligns with the length of the S-NSSAI defined in 3GPP.
Option Data: 4-octet identifier which uniquely identifies a 5G end-
to-end network slice.
3. Procedures
The ingress node of a multi-domain IETF network slice SHOULD
encapsulate the received packet with an MPLS label stack and the VTN
extension header, the Global VTN-ID the packet is mapped to MAY be
carried in the Global VTN-ID option of the VTN extension header.
The edge nodes of each domain MAY parse the Global VTN-ID in the VTN
extension header and maps it to a local VTN. When the mechanism as
defined in [I-D.li-mpls-enhanced-vpn-vtn-id] is used in the local
domain, the Local VTN-ID is obtained from the mapping relationship
between the Global VTN-ID and Local VTN-ID maintained on the edge
node, and the Local VTN-ID SHOULD be encapsulated in the VTN
extension header. The Local VTN-ID is used to identify the local
network resources reserved for the VTN in the local domain. The
local VTN-ID in the packet MAY be updated on the edge nodes of each
domain.
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When the multi-domain IETF network slice is part of a 5G end-to-end
network slice, the 5G Network Slice ID option MAY be carried in the
VTN extension header. The S-NSSAI MAY be used for the collection and
report of the performance information of the 5G end-to-end network
slice in the transport network.
4. IANA Considerations
IANA is requested to assign two option types of the VTN extension
header.
Value Description Reference
-------------------------------------------------
TBD1 Global VTN-ID Option this document
TBD2 5G Network Slice ID Option this document
5. Security Considerations
TBD
6. Acknowledgements
TBD
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 Networks (VPN+)
Service", draft-ietf-teas-enhanced-vpn-06 (work in
progress), July 2020.
[I-D.ietf-teas-ietf-network-slice-definition]
Rokui, R., Homma, S., Makhijani, K., Contreras, L., and J.
Tantsura, "Definition of IETF Network Slices", draft-ietf-
teas-ietf-network-slice-definition-00 (work in progress),
January 2021.
[I-D.ietf-teas-ietf-network-slice-framework]
Gray, E. and J. Drake, "Framework for IETF Network
Slices", March 2021, <https://tools.ietf.org/html/draft-
ietf-teas-ietf-network-slice-framework>.
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[I-D.li-mpls-enhanced-vpn-vtn-id]
Li, Z. and J. Dong, "Carrying Virtual Transport Network
Identifier in MPLS Packet", draft-li-mpls-enhanced-vpn-
vtn-id-01 (work in progress), April 2021.
[I-D.li-teas-e2e-ietf-network-slicing]
Li, Z. and J. Dong, "Framework for End-to-End IETF Network
Slicing", April 2021, <https://tools.ietf.org/html/draft-
li-teas-e2e-ietf-network-slicing>.
[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-enhanced-vpn-vtn-scalability]
Dong, J., Li, Z., Qin, F., and G. Yang, "Scalability
Considerations for Enhanced VPN (VPN+)", draft-dong-teas-
enhanced-vpn-vtn-scalability-01 (work in progress),
November 2020.
Authors' Addresses
Zhenbin Li
Huawei Technologies
Huawei Campus, No. 156 Beiqing Road
Beijing 100095
China
Email: lizhenbin@huawei.com
Jie Dong
Huawei Technologies
Huawei Campus, No. 156 Beiqing Road
Beijing 100095
China
Email: jie.dong@huawei.com
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