6MAN working group J. Dong
Internet-Draft Z. Li
Intended status: Standard Track Huawei
Expires: August 2020 February 10, 2020
Carrying Virtual Transport Network (VTN) Identifier in IPv6
Extensison Header for Enhanced VPN
draft-dong-6man-enhanced-vpn-vtn-id-00
Abstract
This document proposes a new option type to carry virtual transport
network identifier (VTN ID) in the IPv6 extensions headers to
identify the virtual transport network the packet belongs to. The
procedure of processing the VTN option is also specified. This
provides a scalable solution for data plane encapsulation of
enhanced VPN (VPN+) as described in I-D.ietf-teas-enhanced-vpn. One
typical use case of VPN+ is to provide transport network slicing in
5G, while it could also be used in more general cases.
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Copyright Notice
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document authors. All rights reserved.
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Table of Contents
1. Introduction ................................................ 2
2. Requirements Language ....................................... 3
3. New IPv6 Extension Header Option for VTN .................... 3
4. Procedures .................................................. 4
4.1. VTN Option Insertion ................................... 4
4.2. VTN based Packet Forwarding ............................ 5
5. Security Considerations ..................................... 5
IANA Considerations ............................................ 5
Contributors ................................................... 6
Acknowledgments ................................................ 6
References ..................................................... 6
Normative References ........................................ 6
Informative References ...................................... 6
Authors' Addresses ............................................. 7
1. Introduction
Virtual private networks (VPNs) have served the industry well as a
means of providing different groups of users with logically isolated
connectivity over a common network. Some customers may request a
connectivity services with advanced characteristics such as complete
isolation from other services or guaranteed performance. These
services are "enhanced VPNs" (known as VPN+). [I-D.ietf-teas-
enhanced-vpn] describes the framework and candidate component
technologies for providing enhanced VPN services. One typical use
case of VPN+ is to provide transport network slicing in 5G, while it
could also be used in more general cases.
The enhanced properties of VPN+ require tighter coordination and
integration between the underlay network resources and the overlay
network. VPN+ service is built on a Virtual Transport Network (VTN)
which has a customized network topology and a set of dedicated or
shared network resources allocated from the underlay network. The
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overlay VPN together with the corresponding VTN in the underlay
provide the VPN+ service. In the network, traffic of different VPN+
services need to be processed separately based on the topology and
the network resources associated with the corresponding VTN.
[I-D.dong-teas-enhanced-vpn-vtn-scalability] describes the
scalability considerations of enhanced VPN, in which one approach
to improve the data plane scalability is to introduce a dedicated
identifier indata packet to identify the VTN the packet belongs to,
so as to perform resource specific packet processing. This is called
Resource Independent (RI) VTN.
This document proposes a mechanism to carry the VTN Identifier (VTN
ID) in the IPv6 extensions headers [RFC8200] of packet, so that the
packet will be processed by network nodes using the network
resources allocated to the corresponding VTN. The procedure of
processing the VTN ID is also specified. This provides a scalable
solution for enhanced VPN data plane, so that it could be used to
support a large number of transport network slices in IPv6 network.
2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. New IPv6 Extension Header Option for VTN
A new option type of IPv6 extension headers is defined to carry the
Virtual Transport Network Identifier (VTN ID) in IPv6 packet header.
Its format is shown as below:
Option Option Option
Type Data Len Data
+--------+--------+--------+--------+
|BBCTTTTT|00000100| 4-octet VTN ID |
+--------+--------+--------+--------+
Option Type: 8-bit identifier of the type of option. The type of VTN
option is TBD by IANA. The highest-order bits of the type field are
defined as below:
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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.
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 VTN option SHOULD be set to 4.
Option Data: 4-octet VTN which uniquely identifies a virtual
transport network.
Editor's note: The length of the VTN ID is defined as 4-octet
partially for the matching with the 4-octet network slice identifier
defined in 3GPP [TS23501].
8-bit 24-bit
+------------+-------------------------+
| SST | Slice Differentiator |
+------------+-------------------------+
4. Procedures
4.1. VTN Option Insertion
The VTN option is inserted at the edge of the IPv6 network which
provides enhanced VPN service. On receipt of a data packet, the
ingress node determines the associated enhanced VPN based on traffic
classification or local policies, then it SHOULD insert the
corresponding VTN ID option into the IPv6 extension header of the
packet. If SRv6 is enabled, the VTN option SHOULD be included in the
outer IPv6 header which MAY optionally include the SRH [I-D.ietf-
6man-segment-routing-header].
In order to make the VTN option be processed by each node along the
path, it is RECOMMENDED that the VTN option be carried in the Hop-
by-Hop option header of the IPv6 packet.
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4.2. VTN based Packet Forwarding
On receipt of a packet with the VTN option, each network node which
can support the VTN option SHOULD use the VTN ID to identify the
virtual network the packet belongs to, and the set of local network
resources allocated the processing of the packet. This means the
forwarding behavior is based on both the destination IP address and
the VTN option.
There can be different implementations of allocating local network
resources to the VTNs. On each interface, the resources allocated to
a particular VTN can be considered as a virtual sub-interface with
dedicated bandwidth. In packet forwarding, the IPv6 destination
address of the received packet is used to identify the next-hop and
the outgoing interface, and the VTN ID is used to further identify
the virtual sub-interface which is associated with the VTN on the
outgoing interface.
Routers which do not support Hop-by-Hop options SHOULD ignore this
option and SHOULD forward the packet. Routers which support Hop-by-
Hop Options, but do not recognize the VTN option SHOULD ignore the
option and continue to forward the packet merely based on the
destination IP address.
5. Security Considerations
TBD
IANA Considerations
This document requests IANA to assign a new option type from
"Destination Options and Hop-by-Hop Options" registry.
Value Description Reference
------------------------------------------------------------
TBD Virtual Transport Network Identifier this document
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Contributors
Zhibo Hu
Email: huzhibo@huawei.com
Juhua Xu
Email: xujuhua@huawei.com
Acknowledgments
The authors would like to thank XXX for the review and valuable
comments.
References
Normative References
[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>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200, DOI 10.17487/
RFC8200, July 2017, <https://www.rfc-editor.org/info/
rfc8200>.
Informative 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-04
(work in progress), January 2020.
[I-D.dong-teas-enhanced-vpn-vtn-scalability] Dong, J., Li, Z., Qin,
F., "Scalability Considerations of Enhanced VPN",
draft-dong-teas-enhanced-vpn-vtn-scalability-00
(work in progress), February 2020.
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[] Filsfils, C., Dukes, D.,
Previdi, S., Leddy, J., Matsushima, S., and D. Voyer,
"IPv6 Segment Routing Header (SRH)", draft-ietf-6man-
segment-routing-header-26 (work in progress), October 2019.
[I-D.ietf-spring-srv6-network-programming] Filsfils, C., Camarillo,
P., Leddy, J., Voyer, D., Matsushima, S., and Z. Li, "SRv6
Network Programming", draft-ietf-spring-srv6-network-
programming-07 (work in progress), December 2019.
[TS23501] "3GPP TS23.501", 2019,
<https://portal.3gpp.org/desktopmodules/Specifications/Spe
cificationDetails.aspx?specificationId=3144>.
Authors' Addresses
Jie Dong
Huawei
Email: jie.dong@huawei.com
Zhenbin Li
Huawei
Email: lizhenbin@huawei.com
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