Carrying Virtual Transport Network (VTN) Information in IPv6 Extension Header
draft-ietf-6man-enhanced-vpn-vtn-id-01
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Active".
|
|
|---|---|---|---|
| Authors | Jie Dong , Zhenbin Li , Chongfeng Xie , Chenhao Ma , Gyan Mishra | ||
| Last updated | 2022-07-11 | ||
| Replaces | draft-dong-6man-enhanced-vpn-vtn-id | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Formats | |||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | WG Document | |
| Document shepherd | (None) | ||
| IESG | IESG state | I-D Exists | |
| Consensus boilerplate | Yes | ||
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| Send notices to | (None) |
draft-ietf-6man-enhanced-vpn-vtn-id-01
Network Working Group J. Dong
Internet-Draft Z. Li
Intended status: Standards Track Huawei Technologies
Expires: 12 January 2023 C. Xie
C. Ma
China Telecom
G. Mishra
Verizon Inc.
11 July 2022
Carrying Virtual Transport Network (VTN) Information in IPv6 Extension
Header
draft-ietf-6man-enhanced-vpn-vtn-id-01
Abstract
Virtual Private Networks (VPNs) provide different customers with
logically separated connectivity over a common network
infrastructure. With the introduction and evolvement of 5G and other
network scenarios, some existing or new customers may require
connectivity services with advanced characteristics comparing to
traditional VPNs. Such kind of network service is called enhanced
VPNs (VPN+). VPN+ can be used to deliver IETF network slices, and
could also be used for other application scenarios.
A Virtual Transport Network (VTN) is a virtual underlay network which
consists of a set of dedicated or shared network resources allocated
from the physical underlay network, and is associated with a
customized logical network topology. VPN+ services can be delivered
by mapping one or a group of overlay VPNs to the appropriate VTNs as
the virtual underlay. In packet forwarding, some fields in the data
packet needs to be used to identify the VTN the packet belongs to, so
that the VTN-specific processing can be performed on each node the
packet traverses.
This document proposes a new Hop-by-Hop option of IPv6 extension
header to carry the VTN related information, which could used to
identify the set of network resources allocated to a VTN and the
rules for packet processing. The procedure for processing the VTN
option is also specified.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 12 January 2023.
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
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. New IPv6 Extension Header Option for VTN . . . . . . . . . . 4
3. Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Adding VTN Option to Packet . . . . . . . . . . . . . . . 6
3.2. VTN based Packet Forwarding . . . . . . . . . . . . . . . 6
4. Operational Considerations . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 7
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
9.1. Normative References . . . . . . . . . . . . . . . . . . 8
9.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
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1. Introduction
Virtual Private Networks (VPNs) provide different customers with
logically isolated connectivity over a common network infrastructure.
With the introduction and evolvement of 5G and other network
scenarios, some existing or new customers may require connectivity
services with advanced characteristics comparing to traditional VPNs,
such as resource isolation from other services or guaranteed
performance. Such kind of network service is called enhanced VPN
(VPN+). VPN+ service requires the coordination and integration
between the overlay VPNs and the capability and resources of the
underlay network. VPN+ can be used to deliver IETF network slices
[I-D.ietf-teas-ietf-network-slices].
[I-D.ietf-teas-enhanced-vpn] describes a framework and the candidate
component technologies for providing VPN+ services. It also
introduces the concept of Virtual Transport Network (VTN). A VTN is
a virtual underlay network which consists of a set of dedicated or
shared network resources allocated from the physical underlay
network, and is associated with a logical 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. In packet forwarding,
traffic of different VPN+ services needs to be processed separately
based on the network resources and the logical topology associated
with the corresponding VTN. In the context of network slicing, VTN
and NRP are considered as similar concepts, and NRP can be seen as an
instantiation of VTN.
[I-D.dong-teas-nrp-scalability] describes the scalability
considerations and the possible optimizations for providing a
relatively large number of VTNs for VPN+ services. One approach to
improve the data plane scalability of VTN is to introduce a dedicated
VTN Resource Identifier (VTN Resource ID) in the data packet to
identify the set of network resources allocated to a VTN, so that
VTN-specific packet processing can be performed using that set of
resources, which avoids the possible resource competition with
services in other VTNs. This is called Resource Independent (RI)
VTN. A VTN Resource ID represents a subset of the resources (e.g.
bandwidth, buffer and queuing resources) allocated on a given set of
links and nodes which constitute a logical network topology. The
logical topology associated with a VTN could be defined using
mechanisms such as Multi-Topology [RFC4915], [RFC5120] or Flex-Algo
[I-D.ietf-lsr-flex-algo], etc.
This document proposes a mechanism to carry the VTN resource ID
together with other VTN related information in a new Hop-by-Hop
option called "VTN option" of IPv6 extension header [RFC8200] of IPv6
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packet, so that on each network node along the packet forwarding
path, the VTN option in the packet is parsed, and the obtained VTN
Resource ID is used to instruct the network node to use the set of
network resources allocated to the corresponding VTN to process and
forward the packet. The procedure for processing the VTN option is
also specified. This provides a scalable solution to support a
relatively large number of VTNs in an IPv6 network.
1.1. 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 RFC 2119 [RFC2119] RFC 8174 [RFC8174] when, and only when, they
appear in all capitals, as shown here.
2. New IPv6 Extension Header Option for VTN
A new Hop-by-Hop option type "VTN" is defined to carry the VTN
resource identifier and other VTN related information in an IPv6
packet. Its format is shown as below:
Option Option
Type Data Len
+--------+--------+
|BBCTTTTT| Length |
+--------+--------+--------+--------+
Option | Flags | Reserved |
Data +--------+--------+--------+--------+
| VTN Resource ID |
+--------+--------+--------+--------+
Figure 1. The format of VTN Option
Option Type: 8-bit identifier of the type of option. The type of VTN
option is to be assigned by IANA. The bits of the type field are
defined as below:
* 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 is set to 0 to indicate this
option does not change en route.
* TTTTT To be assigned by IANA.
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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 8.
Flags: 8-bit flags field. The most significant bit is defined in
this document.
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|S|U U U U U U U|
+-+-+-+-+-+-+-+-+
* S (Strict Match): The S flag is used to indicate whether the VTN
Resource ID MUST be strictly matched for the processing of the
packet. When S flag is set to 1, if the VTN resource ID in the
VTN option does not match with any of the VTN resource ID
provisioned on the outgoing interface of the network node, the
packet MUST be dropped. When S flag is set to 0, if the VTN
resource ID in the VTN option does not match with any of the VTN
resource ID provisioned on the outgoing interface of the network
node, the packet SHOULD be forwarded using the default set of
network resource on the outgoing interface.
* U (Unused): These flags are reserved for future use. They SHOULD
be set to 0 on transmission and MUST be ignored on receipt.
Reserved: 3-octet field reserved for future use. SHOULD be set to 0
on transmission and MUST be ignored on receipt.
VTN Resource ID: 4-octet identifier which uniquely identifies the set
of network resources allocated to a VTN.
Note that, if a deployment found it useful, the four-octet VTN
Resource ID field may be derived from the four-octet Single Network
Slice Selection Assistance Information (S-NSSAI) defined in 3GPP
[TS23501].
3. Procedures
As the VTN option needs to be processed by each node along the path
for VTN-specific forwarding, it MUST be carried in IPv6 Hop-by-Hop
options header.
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3.1. Adding VTN Option to Packet
When an ingress node of an IPv6 domain receives a packet, according
to the traffic classification or mapping policy, the packet is
steered into one of the VTNs in the network, then the packet MUST be
encapsulated in an outer IPv6 header, and the Resource ID of the VTN
which the packet is mapped to MUST be carried in the VTN option of
the Hop-by-Hop Options header associated with the outer IPv6 header.
3.2. VTN based Packet Forwarding
On receipt of a packet with the VTN option, each network node which
can process the VTN option in fast path MUST use the VTN Resource ID
to determine the set of local network resources allocated to the VTN
for packet processing. The packet forwarding behavior is based on
both the destination IP address and the VTN Resource ID. More
specifically, the destination IP address is used to determine the
next-hop and the outgoing interface, and VTN Resource ID is used to
determine the set of network resources on the outgoing interface
which are allocated to the VTN for processing and sending the packet.
If the VTN Resource ID does not match with any of the VTN Resource ID
provisioned on the outgoing interface, the S flag in the VTN option
is used to determine whether the packet is dropped or forwarded using
the default set of network resources of the outgoing interface. The
Traffic Class field of the outer IPv6 header MAY be used to provide
differentiated treatment for packets which belong to the same VTN.
The egress node of the IPv6 domain MUST decapsulate the outer IPv6
header and the Hop-by-Hop Options header which includes the VTN
option.
In the forwarding plane, there can be different approaches of
partitioning the local network resources and allocating them to
different VTNs. For example, on one physical interface, a subset of
the forwarding plane resources (e.g. bandwidth and the associated
buffer and queuing resources) can be allocated to a particular VTN
and represented as a virtual sub-interface with reserved bandwidth
resource. In packet forwarding, the IPv6 destination address of the
received packet is used to identify the next-hop and the outgoing
layer-3 interface, and the VTN Resource ID is used to further
identify the virtual sub-interface on the outgoing interface which is
associated with the VTN.
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Network nodes which do not support the processing of Hop-by-Hop
Options header SHOULD ignore the Hop-by-Hop options header and
forward the packet only based on the destination IP address. Network
nodes which support Hop-by-Hop Options header, but do not support the
VTN option SHOULD ignore the VTN option and continue to forward the
packet based on the destination IP address. The network node MAY
process the rest of the Hop-by-Hop options in the Hop-by-Hop Options
header.
4. Operational Considerations
As described in [RFC8200], network nodes may be configured to ignore
the Hop-by-Hop Options header, drop packets containing a Hop-by-Hop
Options header, or assign packets containing a Hop-by-Hop Options
header to a slow processing path. [I-D.ietf-6man-hbh-processing]
specifies the modified procedures for the processing of IPv6 Hop-by-
Hop Options header. Operator needs to make sure that all the network
nodes involved in a VTN can either process the Hop-by-Hop Options
header in the fast path, or ignore the Hop-by-Hop Options header.
Since a VTN is associated with a logical network topology, it is
practical to ensure that all the network nodes involved in that
logical topology support the processing of the Hop-by-Hop Options
header and the VTN option. In other word, packets steered into a VTN
MUST NOT be dropped due to the existence of the Hop-by-Hop Options
header. It is RECOMMENDED to configure all the network nodes
involved in a VTN to process the Hop-by-Hop Options header and the
VTN option if there is a nob for this.
5. IANA Considerations
This document requests IANA to assign a new option type from
"Destination Options and Hop-by-Hop Options" registry.
Value Description Reference
--------------------------------------------
TBA VTN Option this document
6. Security Considerations
The security considerations with IPv6 Hop-by-Hop Options header are
described in [RFC8200], [RFC7045], [RFC9098] and
[I-D.ietf-6man-hbh-processing]. This document introduces a new IPv6
Hop-by-Hop option which is either processed in the fast path or
ignored by network nodes, thus it does not introduce additional
security issues.
7. Contributors
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Zhibo Hu
Email: huzhibo@huawei.com
Lei Bao
Email: baolei7@huawei.com
8. Acknowledgements
The authors would like to thank Juhua Xu, James Guichard, Joel
Halpern, Tom Petch, Aijun Wang, Zhenqiang Li, Tom Herbert, Adrian
Farrel and Eric Vyncke for their review and valuable comments.
9. References
9.1. Normative References
[I-D.ietf-6man-hbh-processing]
Hinden, R. M. and G. Fairhurst, "IPv6 Hop-by-Hop Options
Processing Procedures", Work in Progress, Internet-Draft,
draft-ietf-6man-hbh-processing-01, 7 July 2022,
<https://www.ietf.org/archive/id/draft-ietf-6man-hbh-
processing-01.txt>.
[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-10, 6 March 2022,
<https://www.ietf.org/archive/id/draft-ietf-teas-enhanced-
vpn-10.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>.
[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>.
9.2. Informative References
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[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-02, 16 May 2022,
<https://www.ietf.org/archive/id/draft-dong-teas-nrp-
scalability-02.txt>.
[I-D.ietf-lsr-flex-algo]
Psenak, P., Hegde, S., Filsfils, C., Talaulikar, K., and
A. Gulko, "IGP Flexible Algorithm", Work in Progress,
Internet-Draft, draft-ietf-lsr-flex-algo-20, 18 May 2022,
<https://www.ietf.org/archive/id/draft-ietf-lsr-flex-algo-
20.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-12, 30 June 2022,
<https://www.ietf.org/archive/id/draft-ietf-teas-ietf-
network-slices-12.txt>.
[RFC4915] Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P.
Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF",
RFC 4915, DOI 10.17487/RFC4915, June 2007,
<https://www.rfc-editor.org/info/rfc4915>.
[RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
Topology (MT) Routing in Intermediate System to
Intermediate Systems (IS-ISs)", RFC 5120,
DOI 10.17487/RFC5120, February 2008,
<https://www.rfc-editor.org/info/rfc5120>.
[RFC7045] Carpenter, B. and S. Jiang, "Transmission and Processing
of IPv6 Extension Headers", RFC 7045,
DOI 10.17487/RFC7045, December 2013,
<https://www.rfc-editor.org/info/rfc7045>.
[RFC9098] Gont, F., Hilliard, N., Doering, G., Kumari, W., Huston,
G., and W. Liu, "Operational Implications of IPv6 Packets
with Extension Headers", RFC 9098, DOI 10.17487/RFC9098,
September 2021, <https://www.rfc-editor.org/info/rfc9098>.
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[RFC9099] Vyncke, É., Chittimaneni, K., Kaeo, M., and E. Rey,
"Operational Security Considerations for IPv6 Networks",
RFC 9099, DOI 10.17487/RFC9099, August 2021,
<https://www.rfc-editor.org/info/rfc9099>.
[TS23501] "3GPP TS23.501", 2016,
<https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=3144>.
Authors' Addresses
Jie Dong
Huawei Technologies
Huawei Campus, No. 156 Beiqing Road
Beijing
100095
China
Email: jie.dong@huawei.com
Zhenbin Li
Huawei Technologies
Huawei Campus, No. 156 Beiqing Road
Beijing
100095
China
Email: lizhenbin@huawei.com
Chongfeng Xie
China Telecom
China Telecom Beijing Information Science & Technology, Beiqijia
Beijing
102209
China
Email: xiechf@chinatelecom.cn
Chenhao Ma
China Telecom
China Telecom Beijing Information Science & Technology, Beiqijia
Beijing
102209
China
Email: machh@chinatelecom.cn
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Gyan Mishra
Verizon Inc.
Email: gyan.s.mishra@verizon.com
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