Internet DRAFT - draft-herbert-ipv4-udpencap-eh
draft-herbert-ipv4-udpencap-eh
INTERNET-DRAFT T. Herbert
Intended Status: Proposed Standard Quantonium
Expires: September 2019
March 8, 2019
IPv4 Extension Headers and UDP Encapsulated Extension Headers
draft-herbert-ipv4-udpencap-eh-01
Abstract
This specification defines extension headers for IPv4 and a method to
encapsulate extension headers in UDP to facilitate transmission over
the Internet, as well as a definition of an IPv4 flow label. The goal
is to provide a uniform and feasible method of extensibility that is
shared between IPv4 and IPv6.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
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Copyright and License Notice
Copyright (c) 2019 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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(http://trustee.ietf.org/license-info) in effect on the date of
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Table of Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 IPv4 extension headers . . . . . . . . . . . . . . . . . . . 3
1.2 Encapsulating extension headers in UDP . . . . . . . . . . . 3
1.3 The IPv4 flow label . . . . . . . . . . . . . . . . . . . . 4
2 IPv4 extension headers . . . . . . . . . . . . . . . . . . . . 4
2.1 Requirements . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Interaction with standard IPv4 mechanisms . . . . . . . . . 6
2.2.1 IPv4 options and IPv4 extension headers . . . . . . . . 7
2.2.2 IPv4 fragmentation and IPv4 extension headers . . . . . 7
3 Encapsulating extension headers in UDP . . . . . . . . . . . . 7
3.1 Encapsulation format . . . . . . . . . . . . . . . . . . . . 8
3.2 GUE magic numbers . . . . . . . . . . . . . . . . . . . . . 9
3.3 Operation . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.3.1 Sender processing . . . . . . . . . . . . . . . . . . . 10
3.3.2 Destination Processing . . . . . . . . . . . . . . . . . 11
3.3.3 Intermediate device processing . . . . . . . . . . . . . 11
4 The IPv4 flow label . . . . . . . . . . . . . . . . . . . . . . 12
4.1 Sender requirements . . . . . . . . . . . . . . . . . . . . 12
4.2 Receiver requirements . . . . . . . . . . . . . . . . . . . 13
5 Security Considerations . . . . . . . . . . . . . . . . . . . . 14
6 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 14
7 References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
7.1 Normative References . . . . . . . . . . . . . . . . . . . 14
7.2 Informative References . . . . . . . . . . . . . . . . . . 15
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 16
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1 Introduction
This specification defines extension headers for IPv4 and a method to
encapsulate extension headers in UDP to facilitate transmission over
the Internet. An IPv4 flow label is also defined to help intermediate
nodes classify flows for packets with unknown protocols.
1.1 IPv4 extension headers
IPv4 options were defined in [RFC0791] as the means of extending the
IP protocol. IPv4 options have not been successful. Early router
implementations, and even those today, either don't process IPv4
options or relegate them to a slow path effectively making them
unusable for serious applications. IPv4 options are limited to forty
bytes length and, unlike TCP options, no IP options have been defined
that are critical to communications. The upshot is that IPv4 options
have long not been considered an option for deployment [IPNOPT].
IPv6 took a different approach. Extensibility of IPv6 is provided by
extension headers. Optional internet-layer information is encoded in
separate headers that may be placed between the IPv6 header and the
upper-layer header in a packet [RFC8200]. IPv6 extension headers have
had mixed success in deployment in that some intermediate devices
have trouble processing them [RFC7872], however there are several
active proposals in IETF that would make use of them (e.g. [FAST],
[MTUOPT], [IOAM], [SRV6EH]).
This specification proposes that extension headers, those defined for
IPv6, should be usable with IPv4 as a common method of extensibility.
Using extension headers with IPv4 is logically straightforward. The
IPv4 Protocol field is effectively re-designated to be a Next Header
field with the same meaning and semantics as the IPv6 Next Header
field. In this manner, an IPv4 packet can contain any defined IPv6
extension headers that are recast as IPv4 extension headers. These
include Hop-by-Hop Options, Routing Header, Fragment, Destination
Options, Authentication, and Encapsulating Security Payload. In cases
where an extension header contains IPv6 specific information, the
extension header can be adapted for use with IPv4. For instance, a
Routing Header carrying IPv6 addresses to visit could be adapted to
carry IPv4 addresses.
1.2 Encapsulating extension headers in UDP
Deep Packet Inspection (DPI) is a common technique of middleboxes
that has ossified Internet protocols in several ways. Attempts to use
extension headers with IPv4 would likely be problematic for
intermediate devices doing DPI. To address this, extension headers
can be encapsulated in UDP using Generic UDP Encapsulation. The idea
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is to insert a shim GUE/UDP header between an IPv4 (or IPv6) header
and the extension headers. To nodes that don't understand extension
headers, encapsulated extension headers are transparent and packets
appear to be simple UDP/IP packets. To nodes that understand
extension headers and the encapsulation, the GUE/UDP header is
treated as an extension header itself that appears before any other
extension headers.
Hop-by-Hop options are intended to be parsed, processed, and possibly
modified by intermediate nodes in a path. When Hop-by-Hop options are
encapsulated in UDP, consideration needs to be given on how to ensure
robustness. Per [RFC7605], UDP port numbers only have meaning at the
transport endpoints, so if an intermediate node attempts to interpret
a UDP payload based solely on port number it may be incorrect. If a
node were to modify a UDP payload whose type it has misinterpreted,
then systematic silent data corruption ensues. To mitigate this
issue, a magic number can be set in the UDP data that indicates the
payload type. A magic number identifies the payload as being GUE with
high probability to minimize the risk of misintepretation.
Note that the solution to encapsulate extension headers can be used
for both IPv4 and IPv6. Encapsulation serves as workaround for paths
that have problems processing IPv6 extension headers.
1.3 The IPv4 flow label
IPv6 introduced the concept of a flow label that has proven quite
convenient to perform flow classification, such as that needed by
Equal-Cost Multipath (ECMP). The base IPv4 header does not have
reserved bits that could be allocated as a flow label, however the
sixteen bit Identification field can be used as a flow label in
atomic datagrams [RFC6864].
The IPv4 flow label will be most useful in scenarios for which the
existing mechanisms used to classify IPv4 packets, such as parsing
transport layer headers to extract port information, aren't
available. Defining an IPv4 flow label would also be another instance
of backporting a beneficial feature from IPv6 and further unifying
the two protocols.
2 IPv4 extension headers
IPv4 extension headers are optional internet-layer information
encoded in separate headers that may be placed between the IPv4
header and the upper-layer header in a packet. IPv4 extension headers
are based on IPv6 extension headers and share the same basic
properties and semantics [RFC8200].
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Extension headers are numbered from IANA IP Protocol Numbers [IANA-
PN], the same values are used for IPv4 and IPv6. When processing a
sequence of Next Header values in a packet, the first one that is not
an extension header [IANA-EH] indicates that the next item in the
packet is the corresponding upper-layer header. A special "No Next
Header" value is used if there is no upper-layer header.
As illustrated in these examples, an IPv4 packet MAY carry zero, one,
or more extension headers, each identified by the Next Header field
of the preceding header or the Protocol field of the IPv4 header:
+---------------+------------------------
| IPv4 header | TCP header + data
| |
| Protocol = |
| TCP |
+---------------+------------------------
+---------------+----------------+------------------------
| IPv4 header | Hop-by-Hop | TCP header + data
| | |
| Protocol = | Next Header = |
| Hop-by-Hop | TCP |
+---------------+----------------+------------------------
+---------------+----------------+-----------------+-----------------
| IPv4 header | Hop-by-Hop | Fragment header | fragment of TCP
| | | | header + data
| Protocol = | Next Header = | Next Header = |
| Hop-by-Hop | Fragment | TCP |
+---------------+----------------+-----------------+-----------------
2.1 Requirements
IPv4 extension headers normatively assumes the requirements of IPv6
extension headers as defined in [RFC8200] section 4, with the
following modifications:
* References to the IPv6 header are replaced by references to the
IPv4 header.
* ICMP errors sent in the course of processing extension headers
use ICMPv4.
* The IPv4 header Protocol field assumes the same role and
semantics with respect to extension headers as the IPv6 Next
Header field.
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* The Hop-by-Hop Options header is used to carry optional
information that MAY be examined and processed by any node along
a packet's delivery path.
* If a legacy IPv4 destination node, one that does not support
IPv4 extension headers, receives a packet with extension headers
then the packet will be processed as having an unknown protocol.
It is expected that the packet will be discarded and an ICMP
error is generated.
* Extension headers or options that carry IPv6 specific data or
are otherwise specific to IPv6 MUST not be used with IPv4
(Segment Routing [SRV6EH] for example). IPv4 variants of these
might be defined if achieving the same functionality in IPv4 is
desirable.
* References to the IPv6 Payload Length, for instance in
reassembly procedures, are interpreted as being the computed
IPv4 payload length (i.e. IPv4 Total Length minus the length of
the IPv4 header).
The following are modifications to fragmentation and reassembly
requirements:
* References to setting the Payload Length field in the IPv6
header are interpreted to be setting the Total Length in the
IPv4 header taking into account the IPv4 header length.
* When creating or modifying IPv4 headers in packets, the IPv4
header checksum MUST be set correctly.
* Different fragment packets MAY contain different IP options. The
IP header and any options in the reassembled packet are taken
from the first fragment packet (the one with offset of zero).
* If the length and offset of a fragment are such that the Total
Length of the packet reassembled from that fragment would exceed
65,535 octets, then that fragment must be discarded and an ICMP
Parameter Problem, Code 0, message should be sent to the source
of the fragment, pointing to the Fragment Offset field of the
fragment packet.
2.2 Interaction with standard IPv4 mechanisms
IPv4 extension headers may be used concurrently with IPv4 mechanisms
such as IPv4 options and IPv4 fragmentation. This section discusses
the interactions.
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2.2.1 IPv4 options and IPv4 extension headers
An IPv4 packet MAY contain both IPv4 options and extension headers.
IPv4 options are completely independent of IPv4 extension headers.
IPv4 options MUST be processed before processing any extension
headers per normal requirements of processing the IP header before
the IP payload.
2.2.2 IPv4 fragmentation and IPv4 extension headers
An IPv4 packet may be fragmented both by using a Fragment extension
header as well as by standard IPv4 fragmentation. The Fragment header
can only be set at the source, however intermediate devices can
fragment packets using standard IPv4 fragmentation. Standard IPv4
fragmentation at a source node MUST be done only after any extension
headers are set in a packet or the packet was fragmented using the
Fragment header. Specifically, fragmentation using the extension
header MUST NOT be done on packet fragments created by standard IPv4
fragmentation. However, a packet fragment that contains a Fragment
header MAY itself be fragmented by standard IPv4 fragmentation. There
is no correlation between normal IPv4 fragmentation and the IPv4
Fragment header, the identifier space for each are unrelated and
reassembly procedures are independent.
At a destination, if a received packet was fragmented by standard
IPv4 fragmentation, it MUST be reassembled before processing any IPv4
extension headers. This requirement ensures that standard IPv4
reassembly is done before reassembly for the Fragment header.
If an IPv4 packet containing Hop-by-Hop options is fragmented using
standard IPv4 fragmentation, the Hop-by-Hop Options are not set in
each of the packet fragments. An intermediate node MAY process the
Hop-by-Hop options in the first fragment if the complete Hop-by-Hop
extension header is contained within the fragment. If the Fragment
header is used with IPv4 the DF bit (Don't Fragment) bit SHOULD be
set in the IPv4 header and Path MTU discovery mechanisms SHOULD be
used.
3 Encapsulating extension headers in UDP
This section defines a means to carry extension headers in Generic
UDP Encapsulation (GUE). The diagram below illustrates the protocol
stack when extension headers are encapsulated in GUE.
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+-------------------------------+
| IPv4 or IPv6 header |
+-------------------------------+
| UDP header |
|-------------------------------|
| GUE Header |
|-------------------------------|
| |
| Extension headers |
| |
+-------------------------------+
| Transport header |
+-------------------------------+
| Transport payload |
+-------------------------------+
3.1 Encapsulation format
Extension headers and the trailing transport layer packet can be
encapsulated in Variant 0 of GUE. The protocol format is:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+\
| Source port | Destination port | U
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ D
| Length | Checksum | P
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+/
| 0 |C| Hlen | Proto/ctype |G| SEC |F|T|R|K|N|A|M| Rsvd |\
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| G
| | U
~ Optional GUE fields ~ E
| | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+/
| |
~ Extension headers ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Transport packet ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The pertinent fields in the base GUE header are:
o Variant - set 0 for variant 0.
o C bit - Control bit. Set to zero indicating a data message.
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o Hlen - Header length of GUE header in four byte words not
including the first four bytes.
o Proto/ctype - The type of the encapsulated protocol. This is an
IP protocol and may be an extension header. If the payload is
something other than an IP protocol or the payload is encrypted
or transformed, then this field is set to 59 (No Next Header)--
in this case the type of the payload is determined through other
means.
o M: Magic number bit. If this bit is set then the GUE magic
number option is present. The GUE magic number option is
described below.
Any of the GUE options defined in [GUEEXT] MAY be set in the packet.
To facilitate maintaining the correct transport layer checksum across
NAT translation, the NAT address checksum option SHOULD be used
([GUEEXT]). The GUE magic number option, defined below, is used to
help intermediate nodes correctly identify GUE packets.
If a transport layer protocol is encapsulated in GUE then the IP
header for the transport header is taken to be the IP header of the
GUE/UDP packet. In particular, an encapsulated transport header may
have a checksum that includes the IP addresses in a pseudo header for
checksum calculation (TCP or UDP).
3.2 GUE magic numbers
GUE magic numbers are used to identify a UDP payload as being a GUE
payload with a high degree of probability.
The format of the GUE magic number option is:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Magic value = 0xffd871a2b4e7c965 ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The fields of the option are:
o Magic value. A 64 bit value that MUST be set to
0xffd871a2b4e7c965.
The GUE magic number option is present when the M bit is set in the
GUE header flags.
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3.3 Operation
This section describes the operation of encapsulating extension
headers in GUE.
3.3.1 Sender processing
To encapsulate extension headers, a sender inserts a UDP and GUE
header between an IP header and the first extension header.
If a sender encapsulates extension headers in GUE then it MUST NOT
also set extension headers in the IPv4 or IPv6 header. When extension
headers are encapsulated in GUE, the Next Header field of the IPv6
header or the Protocol field of the IPv4 header MUST be set to 17 to
indicate UDP.
If the encapsulated transport protocol contains a checksum with a
pseudo header and the packet may traverse a NAT, then the NAT Address
Checksum option SHOULD be set to allow the receiver to properly
adjust the received transport layer checksum. Other GUE options MAY
be set per the discretion of the sender.
If the packet being encapsulated contains a Hop-by-Hop extension
header then the Magic Number option MUST be used to allow
intermediate nodes to process and potentially modify data in the
extension header. Note that in this case the proto/ctype field in the
GUE header MUST be zero indicating Hop-by-Hop options extension
header.
The following guidelines apply to the source setting the magic number
option:
o If the GUE checksum option is used then its payload coverage
MUST be zero.
o If the GUE alternate checksum option is used then its payload
coverage MUST be zero.
o If the HMAC security option is used then its Payload length MUST
be zero.
o The magic number option MUST NOT be set when the GUE
fragmentation or payload transform option is used.
o The remote checksum option MAY be used concurrently with the
magic number option under the assumption that intermediate nodes
will not modify encapsulated transport checksum fields or
attempt to verify an encapsulated transport layer checksum (in
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the latter case they could do that it they were to take the
remote checksum offload option into account).
3.3.2 Destination Processing
Encapsulated extension headers in GUE are processed by normal methods
of processing GUE. As described in [GUE]:
If a valid data message is received, the UDP header and GUE header
are removed from the packet. The outer IP header remains intact
and the next protocol in the IP header is set to the protocol from
the proto field in the GUE header. The resulting packet is then
resubmitted into the protocol stack to process that packet as
though it was received with the protocol in the GUE header.
In the case that the GUE packet contains extension headers, the
resultant packet after GUE processing is an IPv4 or IPv6 packet with
extension headers. When the packet is resubmitted to the protocol
stack, processing of the first extension header commences.
Note that if a routing header was encapsulated, the packet may be
forwarded to another node. The packet MAY be re-encapsulated in GUE
for transmission per the capabilities of the receiving node and
network.
3.3.3 Intermediate device processing
Intermediate devices MAY process Hop-by-Hop options. In the case that
GUE encapsulates Hop-by-Hop options, an intermediate node needs to
parse, process, and possibly modify a UDP payload containing the GUE
message with encapsulated Hop-by-Hop options. The magic number option
is defined to allow intermediate nodes to identify GUE packets that
might contain Hop-by-Hop options to process.
Processing of packets with encapsulated Hop-by-Hop options has the
following flow:
1) Match destination UDP port number to be GUE.
2) If the GUE variant is not zero or the C bit is set (control
message) then discontinue payload processing.
3) If proto/ctype value is not zero (not Hop-by-Hop options) then
discontinue payload processing.
5) If magic number option is not present in the GUE header then
discontinue payload processing.
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5) Compare the magic number value in the GUE header to the
defined value. If they are not equal then discontinue payload
processing
6) If the GUE checksum option is present (and payload coverage is
zero) then the GUE checksum MAY be validated. If checksum
validation fails, then discontinue payload processing
7) If the alternate checksum is present (and payload coverage is
zero) then the alternate checksum MAY be validated. If
alternate checksum validation fails, then discontinue payload
processing
8) Process the encapsulated Hop-by-Hop options. If a Hop-by-Hop
option is modified then the outer UDP checksum MUST be updated
to reflect the change.
Note that an intermediate node MUST not modify any fields other then
data in modifiable Hop-by-Hop options or the UDP checksum which needs
to be updated when UDP payload is modified. In particular,
intermediate nodes MUST NOT modify the GUE header nor an data aside
from that in modifiable Hop-by-Hop options.
4 The IPv4 flow label
As stated in [RFC6864]:
">> Originating sources MAY set the IPv4 ID field of atomic
datagrams to any value."
This specification allows the IPv4 ID to be used as a flow label in
atomic datagrams. Atomic datagrams are IPv4 packets for which
(DF==1)&&(MF==0)&&(frag_offset==0).
4.1 Sender requirements
An origin host MAY set the IPv4 Identification field as a flow label
in atomic packets. The IPv4 flow label is set following the same
procedures for setting the IPv6 flow label as described in [RFC6437],
with the following modifications:
* The Identification field MUST NOT be used as a flow label in
non-atomic fragments.
* Only stateless flow labels can be set.
* The value to set, e.g. from a hash computation over packet
headers, is truncated to sixteen bits (the size of the
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Identification field).
* If the IPv4 Identification field is not used as a flow label in
atomic fragments, it SHOULD be set to zero.
* Intermediate nodes MUST NOT set the Identification field in
atomic datagrams.
4.2 Receiver requirements
Receivers, including intermediate hosts, MAY process non-zero
Identification fields in IPv4 header of atomic datagrams as being a
flow label. The IPv4 flow label for instance can be used as input to
ECMP as described in [RFC6438].
It is RECOMMENDED that a receiver only consumes the flow label if
other typical means flow classification, such as parsing the
transport layer headers to extract port numbers for the flow, are not
available. For instance, the IPv4 flow label could be used for flow
based packet steering if a router encounters a packet with a protocol
that is unknown to it.
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5 Security Considerations
This specification enables use of IPv6 extension headers in IPv4.
Related security mechanisms of IPv6 extension headers can be applied
for use with IPv4 extension headers.
When extension headers are encapsulated in GUE, normal GUE security
mechanisms can be used. If an intermediate node might modify GUE
payload to process modifiable extension headers, then a GUE security
algorithm cannot take input to authenticate the GUE payload. If
authentication is necessary, then an Authentication header may be
used that treats modifiable data fields as zero-valued octets when
computing or verifying the packet's authenticating value.
The IPv4 flow label has similar security properties as the IPv6 flow
label. If the security intent of the sender is to prevent
intermediate nodes in the network from classifying its traffic into
flows then the IPv4 flow label SHOULD NOT be used.
6 IANA Considerations
IANA is requested to assign a value in the "GUE flag-fields" registry
for the Magic Number option.
+-------------+---------------+-------------+--------------------+
| Flags bits | Field size | Description | Reference |
+-------------+---------------+-------------+--------------------+
| Bit 10 | 8 bytes | Magic number| This document |
+-------------+---------------+-------------+--------------------+
7 References
7.1 Normative References
[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, September
1981.
[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>.
[RFC6864] Touch, J., "Updated Specification of the IPv4 ID Field",
RFC 6864, DOI 10.17487/RFC6864, February 2013,
<https://www.rfc-editor.org/info/rfc6864>.
[GUE] Herbert, T., Yong, L., Zia, )., "Generic UDP
Encapsulation", draft-ietf-intarea-gue-07
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7.2 Informative References
[RFC7872] Gont, F., Linkova, J., Chown, T., and W. Liu, "Observations
on the Dropping of Packets with IPv6 Extension Headers in
the Real World", RFC 7872, DOI 10.17487/RFC7872, June 2016,
<https://www.rfc-editor.org/info/rfc7872>.
[RFC7605] Touch, J., "Recommendations on Using Assigned Transport
Port Numbers", BCP 165, RFC 7605, DOI 10.17487/RFC7605,
August 2015, <https://www.rfc-editor.org/info/rfc7605>.
[RFC6437] Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme,
"IPv6 Flow Label Specification", RFC 6437, DOI
10.17487/RFC6437, November 2011, <https://www.rfc-
editor.org/info/rfc6437>.
[RFC6438] Carpenter, B. and S. Amante, "Using the IPv6 Flow Label for
Equal Cost Multipath Routing and Link Aggregation in
Tunnels", RFC 6438, DOI 10.17487/RFC6438, November 2011,
<https://www.rfc-editor.org/info/rfc6438>.
[IPNOPT] Rodrigo Fonseca, George Manning Porter, Randy H. Katz,
Scott Shenker and Ion Stoica, "IP Options are not an
option",
<https://www2.eecs.berkeley.edu/Pubs/TechRpts/2005/EECS-
2005-24.html>
[FAST] Herbert, T., "Firewall and Service Tickets", draft-herbert-
fast-03
[MTUOPT] Hinden, R. and Fairhurst, G., "IPv6 Minimum Path MTU Hop-
by-Hop Option", draft-hinden-6man-mtu-option-00
[IOAM] F. Brockners, S. Bhandari, V. Govindan, C. Pignataro, H.
Gredler, J. Leddy, S. Youell, T. Mizrahi, D. Mozes, P.
Lapukhov, R. Chang, "Encapsulations for In-situ OAM Data"
draft-brockners-inband-oam-transport-05
[SRV6EH] C. Filsfils, Ed., S. Previdi, J. Leddy, S. Matsushima, D.
Voyer, Ed., "IPv6 Segment Routing Header (SRH)", draft-
ietf-6man-segment-routing-header-16
[IANA-PN] IANA, "Protocol Numbers",
<https://www.iana.org/assignments/protocol-numbers>.
[IANA-EH] IANA, "IPv6 Extension Header Types",
<https://www.iana.org/assignments/ipv6-parameters>.
T. Herbert Expires September 9, 2019 [Page 15]
INTERNET DRAFT draft-herbert-ipv4-udpencap-eh-01 March 8, 2019
[GUEEXT] Herbert, T., Yong, L., and Templin, F., "Extensions for
Generic UDP Encapsulation", draft-ietf-intarea-gue-
extensions-07
Author's Address
Tom Herbert
Quantonium
Santa Clara, CA
USA
Email: tom@quantonium.net
T. Herbert Expires September 9, 2019 [Page 16]
