Internet Engineering Task Force (IETF) F. Maino, Ed.

Internet Engineering Task Force (IETF) F. Maino, Ed.
Request for Comments: 9305 Cisco
Category: Standards Track J. Lemon
ISSN: 2070-1721
P. Agarwal
Innovium
D. Lewis
M. Smith
Cisco
October 2022

Locator/ID Separation Protocol (LISP) Generic Protocol Extension

Abstract

This document describes extensions to the Locator/ID Separation
Protocol (LISP) data plane, via changes to the LISP header, to
support multiprotocol encapsulation and allow the introduction of new
protocol capabilities.

Status of This Memo

This is an Internet Standards Track document.

This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.

Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9305.

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
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in the Revised BSD License.

Table of Contents

1. Introduction
1.1. Conventions
1.2. Definitions of Terms
2. LISP Header without Protocol Extensions
3. LISP Generic Protocol Extension (LISP-GPE)
4. Implementation and Deployment Considerations
4.1. Applicability Statement
4.2. Congestion-Control Functionality
4.3. UDP Checksum
4.3.1. UDP Zero Checksum Handling with IPv6
4.4. DSCP, ECN, TTL, and 802.1Q
5. Backward Compatibility
5.1. Detection of ETR Capabilities
6. IANA Considerations
6.1. LISP-GPE Next Protocol Registry
7. Security Considerations
8. References
8.1. Normative References
8.2. Informative References
Acknowledgments
Contributors
Authors' Addresses

1. Introduction

The LISP data plane is defined in [RFC9300]. It specifies an
encapsulation format that carries IPv4 or IPv6 packets (henceforth
jointly referred to as IP) in a LISP header and outer UDP/IP
transport.

The LISP data plane header does not specify the protocol being
encapsulated and, therefore, is currently limited to encapsulating
only IP packet payloads. Other protocols, most notably the Virtual
eXtensible Local Area Network (VXLAN) protocol [RFC7348] (which
defines a header format similar to LISP), are used to encapsulate
Layer 2 (L2) protocols, such as Ethernet.

This document defines an extension for the LISP header, as defined in
[RFC9300], to indicate the inner protocol, enabling the encapsulation
of Ethernet, IP, or any other desired protocol, all the while
ensuring compatibility with existing LISP deployments.

A flag in the LISP header -- the P-bit -- is used to signal the
presence of the 8-bit 'Next Protocol' field. The 'Next Protocol'
field, when present, uses 8 bits of the field that was allocated to
the Echo-Noncing and Map-Versioning features in [RFC9300]. Those two
features are no longer available when the P-bit is used. However,
appropriate LISP Generic Protocol Extension (LISP-GPE) shim headers
can be defined to specify capabilities that are equivalent to Echo-
Noncing and/or Map-Versioning.

Since all of the reserved bits of the LISP data plane header have
been allocated, LISP-GPE can also be used to extend the LISP data
plane header by defining Next Protocol shim headers that implement
new data plane functions not supported in the LISP header. For
example, the use of the Group-Based Policy (GBP) header [VXLAN-LISP]
or of the In situ Operations, Administration, and Maintenance (IOAM)
header [VXLAN-GPE] with LISP-GPE can be considered an extension to
add support in the data plane for GBP functionalities or IOAM
metadata.

1.1. Conventions

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 BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.

1.2. Definitions of Terms

This document uses terms already defined in [RFC9300].

2. LISP Header without Protocol Extensions

As described in Section 1, the LISP header has no protocol identifier
that indicates the type of payload being carried. Because of this,
LISP is limited to carrying IP payloads.

The LISP header [RFC9300] contains a series of flags (some defined,
some reserved), a 'Nonce/Map-Version' field, and an 'Instance ID/
Locator-Status-Bits' field. The flags provide flexibility to define
how the various fields are encoded. Notably, Flag bit 5 is the last
reserved bit in the LISP header.

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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|N|L|E|V|I|R|K|K| Nonce/Map-Version |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Instance ID/Locator-Status-Bits |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 1: LISP Header

3. LISP Generic Protocol Extension (LISP-GPE)

This document defines two changes to the LISP header in order to
support multiprotocol encapsulation: the introduction of the P-bit
and the definition of a 'Next Protocol' field. This document
specifies the protocol behavior when the P-bit is set to 1; no
changes are introduced when the P-bit is set to 0. The LISP-GPE
header is shown in Figure 2 and described below.

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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|N|L|E|V|I|P|K|K| Nonce/Map-Version/Next Protocol |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Instance ID/Locator-Status-Bits |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 2: LISP-GPE Header

P-Bit: Flag bit 5 is defined as the Next Protocol bit. The P-bit is
set to 1 to indicate the presence of the 8-bit 'Next Protocol'
field.

If the P-bit is clear (0), the LISP header is bit-by-bit equivalent
to the definition in [RFC9300].

When the P-bit is set to 1, bits N, E, and V, and bits 8-23 of the
'Nonce/Map-Version/Next Protocol' field MUST be set to zero on
transmission and MUST be ignored on receipt. Features equivalent to
those that were implemented with bits N, E, and V in [RFC9300], such
as Echo-Noncing and Map-Versioning, can be implemented by defining
appropriate LISP-GPE shim headers.

When the P-bit is set to 1, the LISP-GPE header is encoded as:

0 x 0 0 x 1 x x
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|N|L|E|V|I|P|K|K| 0x0000 | Next Protocol |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Instance ID/Locator-Status-Bits |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 3: LISP-GPE with P-bit Set to 1

Next Protocol: When the P-bit is set to 1, the lower 8 bits of the
first 32-bit word are used to carry a Next Protocol. This 'Next
Protocol' field contains the protocol of the encapsulated payload
packet.

This document defines the following Next Protocol values:

0x00: Reserved

0x01: IPv4

0x02: IPv6

0x03: Ethernet

0x04: Network Service Header (NSH) [RFC8300]

0x05 to 0x7D: Unassigned

0x7E and 0x7F: Experimentation and testing

0x80 to 0xFD: Unassigned (shim headers)

0xFE, 0xFF: Experimentation and testing (shim headers)

The values are tracked in the IANA "LISP-GPE Next Protocol" registry,
as described in Section 6.1.

Next Protocol values 0x7E, 0x7F, 0xFE, and 0xFF are assigned for
experimentation and testing, as per [RFC3692].

Next Protocol values from 0x80 to 0xFD are assigned to protocols
encoded as generic shim headers. All shim protocols MUST use the
header structure in Figure 4, which includes a 'Next Protocol' field.
When shim headers are used with other protocols identified by Next
Protocol values from 0x00 to 0x7F, all the shim headers MUST come
first.

Shim headers can be used to incrementally deploy new GPE features,
keeping the processing of shim headers known to a given Tunnel Router
(xTR) implementation in the 'fast' path (typically an Application-
Specific Integrated Circuit (ASIC)) while punting the processing of
the remaining new GPE features to the 'slow' path.

Shim protocols MUST have the first 32 bits defined as:

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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved | Next Protocol |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Protocol-Specific Fields ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 4: Shim Header

Where:

Type: This field identifies the different messages of this protocol.

Length: This field indicates the length, in 4-octet units, of this
protocol message, not including the first 4 octets.

Reserved: The use of this field is reserved to the protocol defined
in this message.

Next Protocol: This field contains the protocol of the encapsulated
payload. The values are tracked in the IANA "LISP-GPE Next
Protocol" registry, as described in Section 6.1.

4. Implementation and Deployment Considerations

4.1. Applicability Statement

LISP-GPE conforms, as a UDP-based encapsulation protocol, to the UDP
usage guidelines specified in [RFC8085]. The applicability of these
guidelines is dependent on the underlay IP network and the nature of
the encapsulated payload.

[RFC8085] outlines two applicability scenarios for UDP applications:
1) the general Internet and 2) a controlled environment. A
controlled environment means a single administrative domain or
adjacent set of cooperating domains. A network in a controlled
environment can be managed to operate under certain conditions,
whereas, in the general Internet, this cannot be done. Hence,
requirements for a tunnel protocol operating under a controlled
environment can be less restrictive than the requirements of the
general Internet.

The LISP-GPE scope of applicability is the same set of use cases
covered by [RFC9300] for the LISP data plane protocol. The common
property of these use cases is a large set of cooperating entities
seeking to communicate over the public Internet or other large
underlay IP infrastructures while keeping the addressing and topology
of the cooperating entities separate from the underlay and Internet
topology, routing, and addressing.

LISP-GPE is meant to be deployed in network environments operated by
a single operator or adjacent set of cooperating network operators
that fit with the definition of controlled environments in [RFC8085].

For the purpose of this document, a Traffic-Managed Controlled
Environment (TMCE), outlined in [RFC8086], is defined as an IP
network that is traffic-engineered and/or otherwise managed (e.g.,
via the use of traffic rate limiters) to avoid congestion.
Significant portions of the text in this section are based on
[RFC8086].

It is the responsibility of the network operators to ensure that the
guidelines/requirements in this section are followed as applicable to
their LISP-GPE deployments.

4.2. Congestion-Control Functionality

LISP-GPE does not provide congestion-control functionality and relies
on the payload protocol traffic for congestion control. As such,
LISP-GPE MUST be used with congestion-controlled traffic or within a
network that is traffic managed to avoid congestion (TMCE). An
operator of a traffic-managed network (TMCE) may avoid congestion by
careful provisioning of their networks, rate limiting of user data
traffic, and traffic engineering according to path capacity.

Keeping in mind the recommendation above, new encapsulated payloads,
when registered with LISP-GPE, MUST be accompanied by a set of
guidelines derived from Section 5 of [RFC9300]. Such new protocols
should be designed for explicit congestion signals to propagate
consistently from lower-layer protocols into IP. Then, the IP
internetwork layer can act as a portability layer to carry congestion
notifications from non-IP-aware congested nodes up to the transport
layer (L4). By following the guidelines in [ENCAP-GUIDE], subnetwork
designers can enable a Layer 2 protocol to participate in congestion
control without dropping packets, via propagation of Explicit
Congestion Notification (ECN) data [RFC3168] to receivers.

4.3. UDP Checksum

For IP payloads, Section 5.3 of [RFC9300] specifies how to handle UDP
checksums, encouraging implementors to consider UDP checksum usage
guidelines in Section 3.4 of [RFC8085] when it is desirable to
protect UDP and LISP headers against corruption.

In order to protect the integrity of LISP-GPE headers, options, and
payloads (for example, to avoid misdelivery of payloads to different
tenant systems in the case of data corruption), the outer UDP
checksum SHOULD be used with LISP-GPE when transported over IPv4.
The UDP checksum provides a statistical guarantee that a payload was
not corrupted in transit. These integrity checks are not strong from
a coding or cryptographic perspective and are not designed to detect
physical-layer errors or malicious modifications of the datagram (see
Section 3.4 of [RFC8085]). In deployments where such a risk exists,
an operator SHOULD use additional data integrity mechanisms, such as
those offered by IPsec.

An operator MAY choose to disable a UDP checksum and use a zero
checksum if LISP-GPE packet integrity is provided by other data
integrity mechanisms, such as IPsec or additional checksums, or if
one of the conditions in Section 4.3.1 (a, b, or c) is met.

4.3.1. UDP Zero Checksum Handling with IPv6

By default, a UDP checksum MUST be used when LISP-GPE is transported
over IPv6. A tunnel endpoint MAY be configured for use with a zero
UDP checksum if additional requirements described in this section are
met.

When LISP-GPE is used over IPv6, a UDP checksum is used to protect
IPv6 headers, UDP headers, and LISP-GPE headers and payloads from
potential data corruption. As such, by default, LISP-GPE MUST use a
UDP checksum when transported over IPv6. An operator MAY choose to
configure to operate with a zero UDP checksum if operating in a
traffic-managed controlled environment, as stated in Section 4.1, if
one of the following conditions is met:

a. It is known that packet corruption is exceptionally unlikely
(perhaps based on an operator's knowledge of equipment types in
their underlay network), and the operator is willing to take the
risk of undetected packet corruption.

b. It is determined through observational measurements (perhaps
through historic or current traffic flows that use a non-zero
checksum) that the level of packet corruption is tolerably low,
and the operator is willing to take the risk of undetected
corruption.

c. LISP-GPE payloads are carrying applications that are tolerant of
misdelivered or corrupted packets (perhaps through higher-layer
checksum validation and/or reliability through retransmission).

In addition, LISP-GPE tunnel implementations using a zero UDP
checksum MUST meet the following requirements:

1. Use of a UDP checksum over IPv6 MUST be the default configuration
for all LISP-GPE tunnels.

2. If LISP-GPE is used with a zero UDP checksum over IPv6, then such
xTR implementations MUST meet all the requirements specified in
Section 4 of [RFC6936] and requirement 1 specified in Section 5
of [RFC6936].

3. The Egress Tunnel Router (ETR) that decapsulates the packet
SHOULD check that the source and destination IPv6 addresses are
valid for the LISP-GPE tunnel that is configured to receive a
zero UDP checksum and discard other packets that fail such
checks.

4. The Ingress Tunnel Router (ITR) that encapsulates the packet MAY
use different IPv6 source addresses for each LISP-GPE tunnel that
uses zero UDP checksum mode in order to strengthen the
decapsulator's check of the IPv6 source address (i.e., the same
IPv6 source address is not to be used with more than one IPv6
destination address, irrespective of whether that destination
address is a unicast or multicast address). When this is not
possible, it is RECOMMENDED to use each source address for as few
LISP-GPE tunnels that use a zero UDP checksum as is feasible.

5. Measures SHOULD be taken to prevent LISP-GPE traffic over IPv6
with a zero UDP checksum from escaping into the general Internet.
Examples of such measures include employing packet filters at the
Proxy Egress Tunnel Router (PETR) and/or keeping logical or
physical separation of the LISP network from networks in the
general Internet.

The above requirements do not change the requirements specified in
[RFC6935], [RFC6936], or [RFC8200].

The requirement to check the source IPv6 address in addition to the
destination IPv6 address, plus the recommendation against the reuse
of source IPv6 addresses among LISP-GPE tunnels, collectively provide
some mitigation for the absence of UDP checksum coverage of the IPv6
header. A traffic-managed controlled environment that satisfies at
least one of the three conditions listed at the beginning of this
section provides additional assurance.

4.4. DSCP, ECN, TTL, and 802.1Q

When encapsulating IP (including over Ethernet) packets, [RFC2983]
provides guidance for mapping packets that contain Differentiated
Services Code Point (DSCP) information between inner and outer IP
headers. The Pipe model typically fits better with network
virtualization. The DSCP value on the tunnel header is set based on
a policy (which may be a fixed value, one based on the inner traffic
class, or some other mechanism for grouping traffic). Some aspects
of the Uniform model (which treats the inner and outer DSCP value as
a single field by copying on ingress and egress) may also apply, such
as the ability to remark the inner header on tunnel egress based on
transit marking. However, the Uniform model is not conceptually
consistent with network virtualization, which seeks to provide strong
isolation between encapsulated traffic and the physical network.

[RFC6040] describes the mechanism for exposing ECN capabilities on IP
tunnels and propagating congestion markers to the inner packets.
This behavior MUST be followed for IP packets encapsulated in LISP-
GPE.

Though the Uniform model or the Pipe model could be used for TTL (or
Hop Limit in the case of IPv6) handling when tunneling IP packets,
the Pipe model is more aligned with network virtualization.
[RFC2003] provides guidance on handling TTL between inner IP headers
and outer IP tunnels; this model is more aligned with the Pipe model
and is recommended for use with LISP-GPE for network-virtualization
applications.

When a LISP-GPE router performs Ethernet encapsulation, the inner
802.1Q 3-bit Priority Code Point ('PCP') field [IEEE.802.1Q_2014] MAY
be mapped from the encapsulated frame to the DSCP codepoint of the
Differentiated Services ('DS') field defined in [RFC2474].

When a LISP-GPE router performs Ethernet encapsulation, the inner-
header 802.1Q VLAN Identifier (VID) [IEEE.802.1Q_2014] MAY be mapped
to, or used to determine, the LISP 'Instance ID' (IID) field.

Refer to Section 7 for considerations about the use of integrity
protection for deployments, such as the public Internet, concerned
with on-path attackers.

5. Backward Compatibility

LISP-GPE uses the same UDP destination port (4341) allocated to LISP.

When encapsulating IP packets to a non-LISP-GPE-capable router, the
P-bit MUST be set to 0. That is, the encapsulation format defined in
this document MUST NOT be sent to a router that has not indicated
that it supports this specification, because such a router would
ignore the P-bit (as described in [RFC9300]) and so would
misinterpret the other LISP header fields, possibly causing
significant errors.

5.1. Detection of ETR Capabilities

The discovery of xTR capabilities to support LISP-GPE is out of the
scope of this document. Given that the applicability domain of LISP-
GPE is a traffic-managed controlled environment, ITR/ETR (xTR)
configuration mechanisms may be used for this purpose.

6. IANA Considerations

6.1. LISP-GPE Next Protocol Registry

IANA has created a registry called "LISP-GPE Next Protocol". These
are 8-bit values. Next Protocol values in the table below are
defined in this document. New values are assigned under the
Specification Required policy [RFC8126]. The protocols that are
being assigned values do not themselves need to be IETF Standards
Track protocols.

+===============+=============================+===========+
| Next Protocol | Description | Reference |
+===============+=============================+===========+
| 0x00 | Reserved | RFC 9305 |
+---------------+-----------------------------+-----------+
| 0x01 | IPv4 | RFC 9305 |
+---------------+-----------------------------+-----------+
| 0x02 | IPv6 | RFC 9305 |
+---------------+-----------------------------+-----------+
| 0x03 | Ethernet | RFC 9305 |
+---------------+-----------------------------+-----------+
| 0x04 | NSH | RFC 9305 |
+---------------+-----------------------------+-----------+
| 0x05-0x7D | Unassigned | |
+---------------+-----------------------------+-----------+
| 0x7E-0x7F | Experimentation and testing | RFC 9305 |
+---------------+-----------------------------+-----------+
| 0x80-0xFD | Unassigned (shim headers) | |
+---------------+-----------------------------+-----------+
| 0xFE-0xFF | Experimentation and testing | RFC 9305 |
| | (shim headers) | |
+---------------+-----------------------------+-----------+

Table 1

7. Security Considerations

LISP-GPE security considerations are similar to the LISP security
considerations and mitigation techniques documented in [RFC7835].

As is the case for many encapsulations that use optional extensions,
LISP-GPE is subject to on-path adversaries that can make arbitrary
modifications to the packet (including the P-bit) to change or remove
any part of the payload, or claim to encapsulate any protocol payload
type. Typical integrity protection mechanisms (such as IPsec) SHOULD
be used in combination with LISP-GPE by those protocol extensions
that want to protect against on-path attackers.

With LISP-GPE, issues such as data plane spoofing, flooding, and
traffic redirection may depend on the particular protocol payload
encapsulated.

8. References

8.1. Normative References

[IEEE.802.1Q_2014]
IEEE, "IEEE Standard for Local and metropolitan area
networks--Bridges and Bridged Networks", IEEE Std 802.1Q-
2014, December 2014,
<https://ieeexplore.ieee.org/document/6991462>.

[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>.

[RFC6040] Briscoe, B., "Tunnelling of Explicit Congestion
Notification", RFC 6040, DOI 10.17487/RFC6040, November
2010, <https://www.rfc-editor.org/info/rfc6040>.

[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>.

[RFC9300] Farinacci, D., Fuller, V., Meyer, D., Lewis, D., and A.
Cabellos, Ed., "The Locator/ID Separation Protocol
(LISP)", RFC 9300, DOI 10.17487/RFC9300, October 2022,
<https://www.rfc-editor.org/info/rfc9300>.

8.2. Informative References

[ENCAP-GUIDE]
Briscoe, B. and J. Kaippallimalil, "Guidelines for Adding
Congestion Notification to Protocols that Encapsulate IP",
Work in Progress, Internet-Draft, draft-ietf-tsvwg-ecn-
encap-guidelines-17, 11 July 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-tsvwg-
ecn-encap-guidelines-17>.

[RFC2003] Perkins, C., "IP Encapsulation within IP", RFC 2003,
DOI 10.17487/RFC2003, October 1996,
<https://www.rfc-editor.org/info/rfc2003>.

[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers", RFC 2474,
DOI 10.17487/RFC2474, December 1998,
<https://www.rfc-editor.org/info/rfc2474>.

[RFC2983] Black, D., "Differentiated Services and Tunnels",
RFC 2983, DOI 10.17487/RFC2983, October 2000,
<https://www.rfc-editor.org/info/rfc2983>.

[RFC3168] Ramakrishnan, K., Floyd, S., and D. Black, "The Addition
of Explicit Congestion Notification (ECN) to IP",
RFC 3168, DOI 10.17487/RFC3168, September 2001,
<https://www.rfc-editor.org/info/rfc3168>.

[RFC3692] Narten, T., "Assigning Experimental and Testing Numbers
Considered Useful", BCP 82, RFC 3692,
DOI 10.17487/RFC3692, January 2004,
<https://www.rfc-editor.org/info/rfc3692>.

[RFC6935] Eubanks, M., Chimento, P., and M. Westerlund, "IPv6 and
UDP Checksums for Tunneled Packets", RFC 6935,
DOI 10.17487/RFC6935, April 2013,
<https://www.rfc-editor.org/info/rfc6935>.

[RFC6936] Fairhurst, G. and M. Westerlund, "Applicability Statement
for the Use of IPv6 UDP Datagrams with Zero Checksums",
RFC 6936, DOI 10.17487/RFC6936, April 2013,
<https://www.rfc-editor.org/info/rfc6936>.

[RFC7348] Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger,
L., Sridhar, T., Bursell, M., and C. Wright, "Virtual
eXtensible Local Area Network (VXLAN): A Framework for
Overlaying Virtualized Layer 2 Networks over Layer 3
Networks", RFC 7348, DOI 10.17487/RFC7348, August 2014,
<https://www.rfc-editor.org/info/rfc7348>.

[RFC7835] Saucez, D., Iannone, L., and O. Bonaventure, "Locator/ID
Separation Protocol (LISP) Threat Analysis", RFC 7835,
DOI 10.17487/RFC7835, April 2016,
<https://www.rfc-editor.org/info/rfc7835>.

[RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage
Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085,
March 2017, <https://www.rfc-editor.org/info/rfc8085>.

[RFC8086] Yong, L., Ed., Crabbe, E., Xu, X., and T. Herbert, "GRE-
in-UDP Encapsulation", RFC 8086, DOI 10.17487/RFC8086,
March 2017, <https://www.rfc-editor.org/info/rfc8086>.

[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.

[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>.

[RFC8300] Quinn, P., Ed., Elzur, U., Ed., and C. Pignataro, Ed.,
"Network Service Header (NSH)", RFC 8300,
DOI 10.17487/RFC8300, January 2018,
<https://www.rfc-editor.org/info/rfc8300>.

[VXLAN-GPE]
Brockners, F., Bhandari, S., Govindan, V., Pignataro, C.,
Gredler, H., Leddy, J., Youell, S., Mizrahi, T., Kfir, A.,
Gafni, B., Lapukhov, P., and M. Spiegel, "VXLAN-GPE
Encapsulation for In-situ OAM Data", Work in Progress,
Internet-Draft, draft-brockners-ippm-ioam-vxlan-gpe-03, 4
November 2019, <https://datatracker.ietf.org/doc/html/
draft-brockners-ippm-ioam-vxlan-gpe-03>.

[VXLAN-LISP]
Lemon, J., Ed., Maino, F., Smith, M., and A. Isaac, "Group
Policy Encoding with VXLAN-GPE and LISP-GPE", Work in
Progress, Internet-Draft, draft-lemon-vxlan-lisp-gpe-gbp-
02, 30 April 2019, <https://datatracker.ietf.org/doc/html/
draft-lemon-vxlan-lisp-gpe-gbp-02>.

Acknowledgments

A special thank you goes to Dino Farinacci for his guidance and
detailed review. Thanks to Tom Herbert for the suggestion to assign
codepoints for experimentations and testing.

Contributors

The editor of this document would like to thank and recognize the
following coauthors and contributors for their contributions. These
coauthors and contributors provided invaluable concepts and content
for this document's creation.

Darrel Lewis
Cisco Systems, Inc.

Fabio Maino
Cisco Systems, Inc.

Paul Quinn
Cisco Systems, Inc.

Michael Smith
Cisco Systems, Inc.

Navindra Yadav
Cisco Systems, Inc.

Larry Kreeger

Jennifer Lemon
Broadcom

Puneet Agarwal
Innovium

Authors' Addresses

Fabio Maino (editor)
Cisco Systems
San Jose, CA
United States of America
Email: [email protected]

Jennifer Lemon
Email: [email protected]

Puneet Agarwal
Innovium
United States of America
Email: [email protected]

Darrel Lewis
Cisco Systems
San Jose, CA
United States of America
Email: [email protected]

Michael Smith
Cisco Systems
San Jose, CA 95134
United States of America
Email: [email protected]