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<pre>Internet Engineering Task Force (IETF) A. Morton
Request for Comments: 8468 AT&T Labs
Updates: <a href="./rfc2330">2330</a> J. Fabini
Category: Informational TU Wien
ISSN: 2070-1721 N. Elkins
Inside Products, Inc.
M. Ackermann
Blue Cross Blue Shield of Michigan
V. Hegde
Consultant
November 2018
<span class="h1">IPv4, IPv6, and IPv4-IPv6 Coexistence:</span>
<span class="h1">Updates for the IP Performance Metrics (IPPM) Framework</span>
Abstract
This memo updates the IP Performance Metrics (IPPM) framework defined
by <a href="./rfc2330">RFC 2330</a> with new considerations for measurement methodology and
testing. It updates the definition of standard-formed packets to
include IPv6 packets, deprecates the definition of minimal IP packet,
and augments distinguishing aspects, referred to as Type-P, for test
packets in <a href="./rfc2330">RFC 2330</a>. This memo identifies that IPv4-IPv6 coexistence
can challenge measurements within the scope of the IPPM framework.
Example use cases include, but are not limited to, IPv4-IPv6
translation, NAT, and protocol encapsulation. IPv6 header
compression and use of IPv6 over Low-Power Wireless Area Networks
(6LoWPAN) are considered and excluded from the standard-formed packet
evaluation.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
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). Not all documents
approved by the IESG are candidates for any level of Internet
Standard; see <a href="./rfc7841#section-2">Section 2 of RFC 7841</a>.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
<a href="https://www.rfc-editor.org/info/rfc8468">https://www.rfc-editor.org/info/rfc8468</a>.
<span class="grey">Morton, et al. Informational [Page 1]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-2" ></span>
<span class="grey"><a href="./rfc8468">RFC 8468</a> IPPM IPv6 Update November 2018</span>
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to <a href="https://www.rfc-editor.org/bcp/bcp78">BCP 78</a> and the IETF Trust's Legal
Provisions Relating to IETF Documents
(<a href="https://trustee.ietf.org/license-info">https://trustee.ietf.org/license-info</a>) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
This document may contain material from IETF Documents or IETF
Contributions published or made publicly available before November
10, 2008. The person(s) controlling the copyright in some of this
material may not have granted the IETF Trust the right to allow
modifications of such material outside the IETF Standards Process.
Without obtaining an adequate license from the person(s) controlling
the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other
than English.
Table of Contents
<a href="#section-1">1</a>. Introduction . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-3">3</a>
<a href="#section-2">2</a>. Requirements Language . . . . . . . . . . . . . . . . . . . . <a href="#page-3">3</a>
<a href="#section-3">3</a>. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-3">3</a>
<a href="#section-4">4</a>. Packets of Type-P . . . . . . . . . . . . . . . . . . . . . . <a href="#page-4">4</a>
<a href="#section-5">5</a>. Standard-Formed Packets . . . . . . . . . . . . . . . . . . . <a href="#page-5">5</a>
<a href="#section-6">6</a>. NAT, IPv4-IPv6 Transition, and Compression Techniques . . . . <a href="#page-9">9</a>
<a href="#section-7">7</a>. Security Considerations . . . . . . . . . . . . . . . . . . . <a href="#page-10">10</a>
<a href="#section-8">8</a>. IANA Considerations . . . . . . . . . . . . . . . . . . . . . <a href="#page-10">10</a>
<a href="#section-9">9</a>. References . . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-11">11</a>
<a href="#section-9.1">9.1</a>. Normative References . . . . . . . . . . . . . . . . . . <a href="#page-11">11</a>
<a href="#section-9.2">9.2</a>. Informative References . . . . . . . . . . . . . . . . . <a href="#page-14">14</a>
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-14">14</a>
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-15">15</a>
<span class="grey">Morton, et al. Informational [Page 2]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-3" ></span>
<span class="grey"><a href="./rfc8468">RFC 8468</a> IPPM IPv6 Update November 2018</span>
<span class="h2"><a class="selflink" id="section-1" href="#section-1">1</a>. Introduction</span>
The IETF IP Performance Metrics (IPPM) working group first created a
framework for metric development in [<a href="./rfc2330" title=""Framework for IP Performance Metrics"">RFC2330</a>]. This framework has
stood the test of time and enabled development of many fundamental
metrics. It has been updated in the area of metric composition
[<a href="./rfc5835" title=""Framework for Metric Composition"">RFC5835</a>] and in several areas related to active stream measurement
of modern networks with reactive properties [<a href="./rfc7312" title=""Advanced Stream and Sampling Framework for IP Performance Metrics (IPPM)"">RFC7312</a>].
The IPPM framework [<a href="./rfc2330" title=""Framework for IP Performance Metrics"">RFC2330</a>] recognized (in <a href="#section-13">Section 13</a>) that many
aspects of an IP packet can influence its processing during transfer
across the network.
In <a href="./rfc2330#section-15">Section 15 of [RFC2330]</a>, the notion of a "standard-formed" packet
is defined. However, the definition was never expanded to include
IPv6, even though the authors of [<a href="./rfc2330" title=""Framework for IP Performance Metrics"">RFC2330</a>] explicitly identified the
need for this update in <a href="#section-15">Section 15</a>: "the version field is 4 (later,
we will expand this to include 6)".
In particular, IPv6 Extension Headers and protocols that use IPv6
header compression are growing in use. This memo seeks to provide
the needed updates to the original definition in [<a href="./rfc2330" title=""Framework for IP Performance Metrics"">RFC2330</a>].
<span class="h2"><a class="selflink" id="section-2" href="#section-2">2</a>. Requirements Language</span>
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
<a href="https://www.rfc-editor.org/bcp/bcp14">BCP 14</a> [<a href="./rfc2119" title=""Key words for use in RFCs to Indicate Requirement Levels"">RFC2119</a>] [<a href="./rfc8174" title=""Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words"">RFC8174</a>] when, and only when, they appear in all
capitals, as shown here.
<span class="h2"><a class="selflink" id="section-3" href="#section-3">3</a>. Scope</span>
The purpose of this memo is to expand the coverage of IPPM to include
IPv6, highlight additional aspects of test packets, and make them
part of the IPPM framework.
The scope is to update key sections of [<a href="./rfc2330" title=""Framework for IP Performance Metrics"">RFC2330</a>], adding
considerations that will aid the development of new measurement
methodologies intended for today's IP networks. Specifically, this
memo expands the Type-P examples in <a href="./rfc2330#section-13">Section 13 of [RFC2330]</a> and
expands the definition (in <a href="./rfc2330#section-15">Section 15 of [RFC2330]</a>) of a standard-
formed packet to include IPv6 header aspects and other features.
Other topics in [<a href="./rfc2330" title=""Framework for IP Performance Metrics"">RFC2330</a>] that might be updated or augmented are
deferred to future work. This includes the topics of passive and
various forms of hybrid active/passive measurements.
<span class="grey">Morton, et al. Informational [Page 3]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-4" ></span>
<span class="grey"><a href="./rfc8468">RFC 8468</a> IPPM IPv6 Update November 2018</span>
<span class="h2"><a class="selflink" id="section-4" href="#section-4">4</a>. Packets of Type-P</span>
A fundamental property of many Internet metrics is that the measured
value of the metric depends on characteristics of the IP packet(s)
used to make the measurement. Potential influencing factors include
IP header fields and their values, as well as higher-layer protocol
headers and their values. Consider an IP-connectivity metric: one
obtains different results depending on whether one is interested in,
for example, connectivity for packets destined for well-known TCP
ports or unreserved UDP ports, those with invalid IPv4 checksums, or
those with TTL or Hop Limit of 16. In some circumstances, these
distinctions will result in special treatment of packets in
intermediate nodes and end systems -- for example, if Diffserv
[<a href="./rfc2474" title=""Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers"">RFC2474</a>], Explicit Congestion Notification (ECN) [<a href="./rfc3168" title=""The Addition of Explicit Congestion Notification (ECN) to IP"">RFC3168</a>], Router
Alert [<a href="./rfc6398" title=""IP Router Alert Considerations and Usage"">RFC6398</a>], Hop-by-Hop extensions [<a href="./rfc7045" title=""Transmission and Processing of IPv6 Extension Headers"">RFC7045</a>], or Flow Labels
[<a href="./rfc6437" title=""IPv6 Flow Label Specification"">RFC6437</a>] are used, or in the presence of firewalls or RSVP
reservations.
Because of this distinction, we introduce the generic notion of a
"packet of Type-P", where in some contexts P will be explicitly
defined (i.e., exactly what type of packet we mean), partially
defined (e.g., "with a payload of B octets"), or left generic. Thus,
we may talk about generic IP-Type-P-connectivity or more specific
IP-port-HTTP-connectivity. Some metrics and methodologies may be
fruitfully defined using generic Type-P definitions, which are then
made specific when performing actual measurements.
Whenever a metric's value depends on the type of the packets
involved, the metric's name will include either a specific type or a
phrase such as "Type-P". Thus, we will not define an
"IP-connectivity" metric but instead an "IP-Type-P-connectivity"
metric and/or perhaps an "IP-port-HTTP-connectivity" metric. This
naming convention serves as an important reminder that one must be
conscious of the exact type of traffic being measured.
If the information constituting Type-P at the Source is found to have
changed at the Destination (or at a measurement point between the
Source and Destination, as in [<a href="./rfc5644" title=""IP Performance Metrics (IPPM): Spatial and Multicast"">RFC5644</a>]), then the modified values
MUST be noted and reported with the results. Some modifications
occur according to the conditions encountered in transit (such as
congestion notification) or due to the requirements of segments of
the Source-to-Destination path. For example, the packet length will
change if IP headers are converted to the alternate version/address
family or optional Extension Headers are added or removed. Even
header fields like TTL/Hop Limit that typically change in transit may
be relevant to specific tests. For example, Neighbor Discovery
Protocol (NDP) [<a href="./rfc4861" title=""Neighbor Discovery for IP version 6 (IPv6)"">RFC4861</a>] packets are transmitted with the Hop Limit
value set to 255, and the validity test specifies that the Hop Limit
<span class="grey">Morton, et al. Informational [Page 4]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-5" ></span>
<span class="grey"><a href="./rfc8468">RFC 8468</a> IPPM IPv6 Update November 2018</span>
MUST have a value of 255 at the receiver, too. So, while other tests
may intentionally exclude the TTL/Hop Limit value from their Type-P
definition, for this particular test, the correct Hop Limit value is
of high relevance and MUST be part of the Type-P definition.
Local policies in intermediate nodes based on examination of IPv6
Extension Headers may affect measurement repeatability. If
intermediate nodes follow the recommendations of [<a href="./rfc7045" title=""Transmission and Processing of IPv6 Extension Headers"">RFC7045</a>],
repeatability may be improved to some degree.
A closely related note: It would be very useful to know if a given
Internet component (like a host, link, or path) treats equally a
class C of different types of packets. If so, then any one of those
types of packets can be used for subsequent measurement of the
component. This suggests we should devise a metric or suite of
metrics that attempt to determine class C (a designation that has no
relationship to address assignments, of course).
Load-balancing over parallel paths is one particular example where
such a class C would be more complex to determine in IPPM
measurements. Load balancers and routers often use flow identifiers,
computed as hashes (of specific parts) of the packet header, for
deciding among the available parallel paths a packet will traverse.
Packets with identical hashes are assigned to the same flow and
forwarded to the same resource in the load balancer's (or router's)
pool. The presence of a load balancer on the measurement path, as
well as the specific headers and fields that are used for the
forwarding decision, are not known when measuring the path as a black
box. Potential assessment scenarios include the measurement of one
of the parallel paths, and the measurement of all available parallel
paths that the load balancer can use. Therefore, knowledge of a load
balancer's flow definition (alternatively, its class-C-specific
treatment in terms of header fields in scope of hash operations) is a
prerequisite for repeatable measurements. A path may have more than
one stage of load-balancing, adding to class C definition complexity.
<span class="h2"><a class="selflink" id="section-5" href="#section-5">5</a>. Standard-Formed Packets</span>
Unless otherwise stated, all metric definitions that concern IP
packets include an implicit assumption that the packet is standard-
formed. A packet is standard-formed if it meets all of the following
REQUIRED criteria:
+ It includes a valid IP header. See below for version-specific
criteria.
+ It is not an IP fragment.
<span class="grey">Morton, et al. Informational [Page 5]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-6" ></span>
<span class="grey"><a href="./rfc8468">RFC 8468</a> IPPM IPv6 Update November 2018</span>
+ The Source and Destination addresses correspond to the intended
Source and Destination, including Multicast Destination addresses.
+ If a transport header is present, it contains a valid checksum and
other valid fields.
For an IPv4 packet (as specified in [<a href="./rfc791" title=""Internet Protocol"">RFC791</a>] and the RFCs that update
it) to be standard-formed, the following additional criteria are
REQUIRED:
o The version field is 4.
o The Internet Header Length (IHL) value is >= 5; the checksum is
correct.
o Its total length as given in the IPv4 header corresponds to the
size of the IPv4 header plus the size of the payload.
o Either the packet possesses sufficient TTL to travel from the
Source to the Destination if the TTL is decremented by one at each
hop or it possesses the maximum TTL of 255.
o It does not contain IP options unless explicitly noted.
For an IPv6 packet (as specified in [<a href="./rfc8200" title=""Internet Protocol, Version 6 (IPv6) Specification"">RFC8200</a>] and any future updates)
to be standard-formed, the following criteria are REQUIRED:
o The version field is 6.
o Its total length corresponds to the size of the IPv6 header (40
octets) plus the length of the payload as given in the IPv6
header.
o The payload length value for this packet (including Extension
Headers) conforms to the IPv6 specifications.
o Either the packet possesses sufficient Hop Limit to travel from
the Source to the Destination if the Hop Limit is decremented by
one at each hop or it possesses the maximum Hop Limit of 255.
o Either the packet does not contain IP Extension Headers or it
contains the correct number and type of headers as specified in
the packet and the headers appear in the standard-conforming order
(Next Header).
o All parameters used in the header and Extension Headers are found
in the "Internet Protocol Version 6 (IPv6) Parameters" registry
specified in [<a href="#ref-IANA-6P" title=""Internet Protocol Version 6 (IPv6) Parameters"">IANA-6P</a>].
<span class="grey">Morton, et al. Informational [Page 6]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-7" ></span>
<span class="grey"><a href="./rfc8468">RFC 8468</a> IPPM IPv6 Update November 2018</span>
Two mechanisms require some discussion in the context of standard-
formed packets, namely IPv6 over Low-Power Wireless Area Networks
(6LowPAN) [<a href="./rfc4944" title=""Transmission of IPv6 Packets over IEEE 802.15.4 Networks"">RFC4944</a>] and Robust Header Compression (ROHC) [<a href="./rfc3095" title=""RObust Header Compression (ROHC): Framework and four profiles: RTP, UDP, ESP, and uncompressed"">RFC3095</a>].
6LowPAN, as defined in [<a href="./rfc4944" title=""Transmission of IPv6 Packets over IEEE 802.15.4 Networks"">RFC4944</a>] and updated by [<a href="./rfc6282" title=""Compression Format for IPv6 Datagrams over IEEE 802.15.4-Based Networks"">RFC6282</a>] with header
compression and [<a href="./rfc6775" title=""Neighbor Discovery Optimization for IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs)"">RFC6775</a>] with neighbor discovery optimizations,
proposes solutions for using IPv6 in resource-constrained
environments. An adaptation layer enables the transfer of IPv6
packets over networks having an MTU smaller than the minimum IPv6
MTU. Fragmentation and reassembly of IPv6 packets, as well as the
resulting state that would be stored in intermediate nodes, poses
substantial challenges to measurements. Likewise, ROHC operates
statefully in compressing headers on subpaths, storing state in
intermediate hosts. The modification of measurement packets' Type-P
by ROHC and 6LowPAN requires substantial work, as do requirements
with respect to the concept of standard-formed packets for these two
protocols. For these reasons, we consider ROHC and 6LowPAN packets
to be out of the scope of the standard-formed packet evaluation.
The topic of IPv6 Extension Headers brings current controversies into
focus, as noted by [<a href="./rfc6564" title=""A Uniform Format for IPv6 Extension Headers"">RFC6564</a>] and [<a href="./rfc7045" title=""Transmission and Processing of IPv6 Extension Headers"">RFC7045</a>]. However, measurement use
cases in the context of the IPPM framework, such as in situ OAM
[<a href="#ref-IOAM-DATA">IOAM-DATA</a>] in enterprise environments, can benefit from inspection,
modification, addition, or deletion of IPv6 extension headers in
hosts along the measurement path.
[<a id="ref-RFC8250">RFC8250</a>] endorses the use of the IPv6 Destination Option for
measurement purposes, consistent with other relevant and approved
IETF specifications.
The following additional considerations apply when IPv6 Extension
Headers are present:
o Extension Header inspection: Some intermediate nodes may inspect
Extension Headers or the entire IPv6 packet while in transit. In
exceptional cases, they may drop the packet or route via a
suboptimal path, and measurements may be unreliable or
unrepeatable. The packet (if it arrives) may be standard-formed,
with a corresponding Type-P.
o Extension Header modification: In Hop-by-Hop headers, some TLV-
encoded options may be permitted to change at intermediate nodes
while in transit. The resulting packet may be standard-formed,
with a corresponding Type-P.
<span class="grey">Morton, et al. Informational [Page 7]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-8" ></span>
<span class="grey"><a href="./rfc8468">RFC 8468</a> IPPM IPv6 Update November 2018</span>
o Extension Header insertion or deletion: Although such behavior is
not endorsed by current standards, it is possible that Extension
Headers could be added to, or removed from, the header chain. The
resulting packet may be standard-formed, with a corresponding
Type-P. This point simply encourages measurement system designers
to be prepared for the unexpected and notify users when such
events occur. There are issues with Extension Header insertion
and deletion, of course, such as exceeding the path MTU due to
insertion, etc.
o A change in packet length (from the corresponding packet observed
at the Source) or header modification is a significant factor in
Internet measurement and REQUIRES a new Type-P to be reported with
the test results.
It is further REQUIRED that if a packet is described as having a
"length of B octets", then 0 <= B <= 65535; and if B is the payload
length in octets, then B <= (65535-IP header size in octets,
including any Extension Headers). The jumbograms defined in
[<a href="./rfc2675" title=""IPv6 Jumbograms"">RFC2675</a>] are not covered by the above length analysis, but if the
IPv6 Jumbogram Payload Hop-by-Hop Option Header is present, then a
packet with corresponding length MUST be considered standard-formed.
In practice, the path MTU will restrict the length of standard-formed
packets that can successfully traverse the path. Path MTU Discovery
for IP version 6 (PMTUD, [<a href="./rfc8201" title=""Path MTU Discovery for IP version 6"">RFC8201</a>]) or Packetization Layer Path MTU
Discovery (PLPMTUD, [<a href="./rfc4821" title=""Packetization Layer Path MTU Discovery"">RFC4821</a>]) is recommended to prevent
fragmentation.
So, for example, one might imagine defining an IP-connectivity metric
as "IP-Type-P-connectivity for standard-formed packets with the IP
Diffserv field set to 0", or, more succinctly,
"IP-Type-P-connectivity with the IP Diffserv field set to 0", since
standard-formed is already implied by convention. Changing the
contents of a field, such as the Diffserv Code Point, ECN bits, or
Flow Label may have a profound effect on packet handling during
transit, but does not affect a packet's status as standard-formed.
Likewise, the addition, modification, or deletion of extension
headers may change the handling of packets in transit hosts.
[<a id="ref-RFC2330">RFC2330</a>] defines the "minimal IP packet from A to B" as a particular
type of standard-formed packet often useful to consider. When
defining IP metrics, no packet smaller or simpler than this can be
transmitted over a correctly operating IP network. However, the
concept of the minimal IP packet has not been employed (since typical
active measurement systems employ a transport layer and a payload),
and its practical use is limited. Therefore, this memo deprecates
the concept of the "minimal IP packet from A to B".
<span class="grey">Morton, et al. Informational [Page 8]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-9" ></span>
<span class="grey"><a href="./rfc8468">RFC 8468</a> IPPM IPv6 Update November 2018</span>
<span class="h2"><a class="selflink" id="section-6" href="#section-6">6</a>. NAT, IPv4-IPv6 Transition, and Compression Techniques</span>
This memo adds the key considerations for utilizing IPv6 in two
critical conventions of the IPPM framework, namely packets of Type-P
and standard-formed packets. The need for coexistence of IPv4 and
IPv6 has originated transitioning standards like the framework for
IPv4/IPv6 translation in [<a href="./rfc6144" title=""Framework for IPv4/IPv6 Translation"">RFC6144</a>] or the IP/ICMP translation
algorithms in [<a href="./rfc7915" title=""IP/ICMP Translation Algorithm"">RFC7915</a>] and [<a href="./rfc7757" title=""Explicit Address Mappings for Stateless IP/ICMP Translation"">RFC7757</a>].
The definition and execution of measurements within the context of
the IPPM framework is challenged whenever such translation mechanisms
are present along the measurement path. In use cases like IPv4-IPv6
translation, NAT, protocol encapsulation, or IPv6 header compression
may result in modification of the measurement packet's Type-P along
the path. All these changes MUST be reported. Example consequences
include, but are not limited to:
o Modification or addition of headers or header field values in
intermediate nodes. IPv4-IPv6 transitioning or IPv6 header
compression mechanisms may result in changes of the measurement
packets' Type-P, too. Consequently, hosts along the measurement
path may treat packets differently because of the Type-P
modification. Measurements at observation points along the path
may also need extra context to uniquely identify a packet.
o Network Address Translators (NAT) on the path can have an
unpredictable impact on latency measurement (in terms of the
amount of additional time added) and possibly other types of
measurements. It is not usually possible to control this impact
as testers may not have any control of the underlying network or
middleboxes. There is a possibility that stateful NAT will lead
to unstable performance for a flow with specific Type-P, since
state needs to be created for the first packet of a flow and state
may be lost later if the NAT runs out of resources. However, this
scenario does not invalidate the Type-P for testing; for example,
the purpose of a test might be exactly to quantify the NAT's
impact on delay variation. The presence of NAT may mean that the
measured performance of Type-P will change between the source and
the destination. This can cause an issue when attempting to
correlate measurements conducted on segments of the path that
include or exclude the NAT. Thus, it is a factor to be aware of
when conducting measurements.
<span class="grey">Morton, et al. Informational [Page 9]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-10" ></span>
<span class="grey"><a href="./rfc8468">RFC 8468</a> IPPM IPv6 Update November 2018</span>
o Variable delay due to internal state. One side effect of changes
due to IPv4-IPv6 transitioning mechanisms is the variable delay
that intermediate nodes experience for header modifications.
Similar to NAT, the allocation of internal state and establishment
of context within intermediate nodes may cause variable delays,
depending on the measurement stream pattern and position of a
packet within the stream. For example, the first packet in a
stream will typically trigger allocation of internal state in an
intermediate IPv4-IPv6 transition host. Subsequent packets can
benefit from lower processing delay due to the existing internal
state. However, large interpacket delays in the measurement
stream may result in the intermediate host deleting the associated
state and needing to re-establish it on arrival of another stream
packet. It is worth noting that this variable delay due to
internal state allocation in intermediate nodes can be an explicit
use case for measurements.
o Variable delay due to packet length. IPv4-IPv6 transitioning or
header compression mechanisms modify the length of measurement
packets. The modification of the packet size may or may not
change how the measurement path treats the packets.
<span class="h2"><a class="selflink" id="section-7" href="#section-7">7</a>. Security Considerations</span>
The security considerations that apply to any active measurement of
live paths are relevant here as well. See [<a href="./rfc4656" title=""A One-way Active Measurement Protocol (OWAMP)"">RFC4656</a>] and [<a href="./rfc5357" title=""A Two-Way Active Measurement Protocol (TWAMP)"">RFC5357</a>].
When considering the privacy of those involved in measurement or
those whose traffic is measured, the sensitive information available
to potential observers is greatly reduced when using active
techniques that are within this scope of work. Passive observations
of user traffic for measurement purposes raise many privacy issues.
We refer the reader to the privacy considerations described in the
Large Scale Measurement of Broadband Performance (LMAP) framework
[<a href="./rfc7594" title=""A Framework for Large-Scale Measurement of Broadband Performance (LMAP)"">RFC7594</a>], which covers active and passive techniques.
<span class="h2"><a class="selflink" id="section-8" href="#section-8">8</a>. IANA Considerations</span>
This document has no IANA actions.
<span class="grey">Morton, et al. Informational [Page 10]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-11" ></span>
<span class="grey"><a href="./rfc8468">RFC 8468</a> IPPM IPv6 Update November 2018</span>
<span class="h2"><a class="selflink" id="section-9" href="#section-9">9</a>. References</span>
<span class="h3"><a class="selflink" id="section-9.1" href="#section-9.1">9.1</a>. Normative References</span>
[<a id="ref-RFC791">RFC791</a>] Postel, J., "Internet Protocol", STD 5, <a href="./rfc791">RFC 791</a>,
DOI 10.17487/RFC0791, September 1981,
<<a href="https://www.rfc-editor.org/info/rfc791">https://www.rfc-editor.org/info/rfc791</a>>.
[<a id="ref-RFC2119">RFC2119</a>] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", <a href="https://www.rfc-editor.org/bcp/bcp14">BCP 14</a>, <a href="./rfc2119">RFC 2119</a>,
DOI 10.17487/RFC2119, March 1997,
<<a href="https://www.rfc-editor.org/info/rfc2119">https://www.rfc-editor.org/info/rfc2119</a>>.
[<a id="ref-RFC2330">RFC2330</a>] Paxson, V., Almes, G., Mahdavi, J., and M. Mathis,
"Framework for IP Performance Metrics", <a href="./rfc2330">RFC 2330</a>,
DOI 10.17487/RFC2330, May 1998,
<<a href="https://www.rfc-editor.org/info/rfc2330">https://www.rfc-editor.org/info/rfc2330</a>>.
[<a id="ref-RFC2474">RFC2474</a>] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers", <a href="./rfc2474">RFC 2474</a>,
DOI 10.17487/RFC2474, December 1998,
<<a href="https://www.rfc-editor.org/info/rfc2474">https://www.rfc-editor.org/info/rfc2474</a>>.
[<a id="ref-RFC2675">RFC2675</a>] Borman, D., Deering, S., and R. Hinden, "IPv6 Jumbograms",
<a href="./rfc2675">RFC 2675</a>, DOI 10.17487/RFC2675, August 1999,
<<a href="https://www.rfc-editor.org/info/rfc2675">https://www.rfc-editor.org/info/rfc2675</a>>.
[<a id="ref-RFC3095">RFC3095</a>] Bormann, C., Burmeister, C., Degermark, M., Fukushima, H.,
Hannu, H., Jonsson, L-E., Hakenberg, R., Koren, T., Le,
K., Liu, Z., Martensson, A., Miyazaki, A., Svanbro, K.,
Wiebke, T., Yoshimura, T., and H. Zheng, "RObust Header
Compression (ROHC): Framework and four profiles: RTP, UDP,
ESP, and uncompressed", <a href="./rfc3095">RFC 3095</a>, DOI 10.17487/RFC3095,
July 2001, <<a href="https://www.rfc-editor.org/info/rfc3095">https://www.rfc-editor.org/info/rfc3095</a>>.
[<a id="ref-RFC3168">RFC3168</a>] Ramakrishnan, K., Floyd, S., and D. Black, "The Addition
of Explicit Congestion Notification (ECN) to IP",
<a href="./rfc3168">RFC 3168</a>, DOI 10.17487/RFC3168, September 2001,
<<a href="https://www.rfc-editor.org/info/rfc3168">https://www.rfc-editor.org/info/rfc3168</a>>.
[<a id="ref-RFC4656">RFC4656</a>] Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and
M. Zekauskas, "A One-way Active Measurement Protocol
(OWAMP)", <a href="./rfc4656">RFC 4656</a>, DOI 10.17487/RFC4656, September 2006,
<<a href="https://www.rfc-editor.org/info/rfc4656">https://www.rfc-editor.org/info/rfc4656</a>>.
<span class="grey">Morton, et al. Informational [Page 11]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-12" ></span>
<span class="grey"><a href="./rfc8468">RFC 8468</a> IPPM IPv6 Update November 2018</span>
[<a id="ref-RFC4821">RFC4821</a>] Mathis, M. and J. Heffner, "Packetization Layer Path MTU
Discovery", <a href="./rfc4821">RFC 4821</a>, DOI 10.17487/RFC4821, March 2007,
<<a href="https://www.rfc-editor.org/info/rfc4821">https://www.rfc-editor.org/info/rfc4821</a>>.
[<a id="ref-RFC4861">RFC4861</a>] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", <a href="./rfc4861">RFC 4861</a>,
DOI 10.17487/RFC4861, September 2007,
<<a href="https://www.rfc-editor.org/info/rfc4861">https://www.rfc-editor.org/info/rfc4861</a>>.
[<a id="ref-RFC4944">RFC4944</a>] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,
"Transmission of IPv6 Packets over IEEE 802.15.4
Networks", <a href="./rfc4944">RFC 4944</a>, DOI 10.17487/RFC4944, September 2007,
<<a href="https://www.rfc-editor.org/info/rfc4944">https://www.rfc-editor.org/info/rfc4944</a>>.
[<a id="ref-RFC5357">RFC5357</a>] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and
J. Babiarz, "A Two-Way Active Measurement Protocol
(TWAMP)", <a href="./rfc5357">RFC 5357</a>, DOI 10.17487/RFC5357, October 2008,
<<a href="https://www.rfc-editor.org/info/rfc5357">https://www.rfc-editor.org/info/rfc5357</a>>.
[<a id="ref-RFC5644">RFC5644</a>] Stephan, E., Liang, L., and A. Morton, "IP Performance
Metrics (IPPM): Spatial and Multicast", <a href="./rfc5644">RFC 5644</a>,
DOI 10.17487/RFC5644, October 2009,
<<a href="https://www.rfc-editor.org/info/rfc5644">https://www.rfc-editor.org/info/rfc5644</a>>.
[<a id="ref-RFC5835">RFC5835</a>] Morton, A., Ed. and S. Van den Berghe, Ed., "Framework for
Metric Composition", <a href="./rfc5835">RFC 5835</a>, DOI 10.17487/RFC5835, April
2010, <<a href="https://www.rfc-editor.org/info/rfc5835">https://www.rfc-editor.org/info/rfc5835</a>>.
[<a id="ref-RFC6144">RFC6144</a>] Baker, F., Li, X., Bao, C., and K. Yin, "Framework for
IPv4/IPv6 Translation", <a href="./rfc6144">RFC 6144</a>, DOI 10.17487/RFC6144,
April 2011, <<a href="https://www.rfc-editor.org/info/rfc6144">https://www.rfc-editor.org/info/rfc6144</a>>.
[<a id="ref-RFC6282">RFC6282</a>] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6
Datagrams over IEEE 802.15.4-Based Networks", <a href="./rfc6282">RFC 6282</a>,
DOI 10.17487/RFC6282, September 2011,
<<a href="https://www.rfc-editor.org/info/rfc6282">https://www.rfc-editor.org/info/rfc6282</a>>.
[<a id="ref-RFC6398">RFC6398</a>] Le Faucheur, F., Ed., "IP Router Alert Considerations and
Usage", <a href="https://www.rfc-editor.org/bcp/bcp168">BCP 168</a>, <a href="./rfc6398">RFC 6398</a>, DOI 10.17487/RFC6398, October
2011, <<a href="https://www.rfc-editor.org/info/rfc6398">https://www.rfc-editor.org/info/rfc6398</a>>.
[<a id="ref-RFC6437">RFC6437</a>] Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme,
"IPv6 Flow Label Specification", <a href="./rfc6437">RFC 6437</a>,
DOI 10.17487/RFC6437, November 2011,
<<a href="https://www.rfc-editor.org/info/rfc6437">https://www.rfc-editor.org/info/rfc6437</a>>.
<span class="grey">Morton, et al. Informational [Page 12]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-13" ></span>
<span class="grey"><a href="./rfc8468">RFC 8468</a> IPPM IPv6 Update November 2018</span>
[<a id="ref-RFC6564">RFC6564</a>] Krishnan, S., Woodyatt, J., Kline, E., Hoagland, J., and
M. Bhatia, "A Uniform Format for IPv6 Extension Headers",
<a href="./rfc6564">RFC 6564</a>, DOI 10.17487/RFC6564, April 2012,
<<a href="https://www.rfc-editor.org/info/rfc6564">https://www.rfc-editor.org/info/rfc6564</a>>.
[<a id="ref-RFC6775">RFC6775</a>] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and
C. Bormann, "Neighbor Discovery Optimization for IPv6 over
Low-Power Wireless Personal Area Networks (6LoWPANs)",
<a href="./rfc6775">RFC 6775</a>, DOI 10.17487/RFC6775, November 2012,
<<a href="https://www.rfc-editor.org/info/rfc6775">https://www.rfc-editor.org/info/rfc6775</a>>.
[<a id="ref-RFC7045">RFC7045</a>] Carpenter, B. and S. Jiang, "Transmission and Processing
of IPv6 Extension Headers", <a href="./rfc7045">RFC 7045</a>,
DOI 10.17487/RFC7045, December 2013,
<<a href="https://www.rfc-editor.org/info/rfc7045">https://www.rfc-editor.org/info/rfc7045</a>>.
[<a id="ref-RFC7312">RFC7312</a>] Fabini, J. and A. Morton, "Advanced Stream and Sampling
Framework for IP Performance Metrics (IPPM)", <a href="./rfc7312">RFC 7312</a>,
DOI 10.17487/RFC7312, August 2014,
<<a href="https://www.rfc-editor.org/info/rfc7312">https://www.rfc-editor.org/info/rfc7312</a>>.
[<a id="ref-RFC7757">RFC7757</a>] Anderson, T. and A. Leiva Popper, "Explicit Address
Mappings for Stateless IP/ICMP Translation", <a href="./rfc7757">RFC 7757</a>,
DOI 10.17487/RFC7757, February 2016,
<<a href="https://www.rfc-editor.org/info/rfc7757">https://www.rfc-editor.org/info/rfc7757</a>>.
[<a id="ref-RFC7915">RFC7915</a>] Bao, C., Li, X., Baker, F., Anderson, T., and F. Gont,
"IP/ICMP Translation Algorithm", <a href="./rfc7915">RFC 7915</a>,
DOI 10.17487/RFC7915, June 2016,
<<a href="https://www.rfc-editor.org/info/rfc7915">https://www.rfc-editor.org/info/rfc7915</a>>.
[<a id="ref-RFC8174">RFC8174</a>] Leiba, B., "Ambiguity of Uppercase vs Lowercase in <a href="./rfc2119">RFC</a>
<a href="./rfc2119">2119</a> Key Words", <a href="https://www.rfc-editor.org/bcp/bcp14">BCP 14</a>, <a href="./rfc8174">RFC 8174</a>, DOI 10.17487/RFC8174,
May 2017, <<a href="https://www.rfc-editor.org/info/rfc8174">https://www.rfc-editor.org/info/rfc8174</a>>.
[<a id="ref-RFC8200">RFC8200</a>] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, <a href="./rfc8200">RFC 8200</a>,
DOI 10.17487/RFC8200, July 2017,
<<a href="https://www.rfc-editor.org/info/rfc8200">https://www.rfc-editor.org/info/rfc8200</a>>.
[<a id="ref-RFC8201">RFC8201</a>] McCann, J., Deering, S., Mogul, J., and R. Hinden, Ed.,
"Path MTU Discovery for IP version 6", STD 87, <a href="./rfc8201">RFC 8201</a>,
DOI 10.17487/RFC8201, July 2017,
<<a href="https://www.rfc-editor.org/info/rfc8201">https://www.rfc-editor.org/info/rfc8201</a>>.
<span class="grey">Morton, et al. Informational [Page 13]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-14" ></span>
<span class="grey"><a href="./rfc8468">RFC 8468</a> IPPM IPv6 Update November 2018</span>
[<a id="ref-RFC8250">RFC8250</a>] Elkins, N., Hamilton, R., and M. Ackermann, "IPv6
Performance and Diagnostic Metrics (PDM) Destination
Option", <a href="./rfc8250">RFC 8250</a>, DOI 10.17487/RFC8250, September 2017,
<<a href="https://www.rfc-editor.org/info/rfc8250">https://www.rfc-editor.org/info/rfc8250</a>>.
<span class="h3"><a class="selflink" id="section-9.2" href="#section-9.2">9.2</a>. Informative References</span>
[<a id="ref-IANA-6P">IANA-6P</a>] IANA, "Internet Protocol Version 6 (IPv6) Parameters",
<<a href="https://www.iana.org/assignments/ipv6-parameters">https://www.iana.org/assignments/ipv6-parameters</a>>.
[<a id="ref-IOAM-DATA">IOAM-DATA</a>]
Brockners, F., Bhandari, S., Pignataro, C., Gredler, H.,
Leddy, J., Youell, S., Mizrahi, T., Mozes, D., Lapukhov,
P., Chang, R., daniel.bernier@bell.ca, d., and J. Lemon,
"Data Fields for In-situ OAM", Work in Progress,
<a href="./draft-ietf-ippm-ioam-data-03">draft-ietf-ippm-ioam-data-03</a>, June 2018.
[<a id="ref-RFC7594">RFC7594</a>] Eardley, P., Morton, A., Bagnulo, M., Burbridge, T.,
Aitken, P., and A. Akhter, "A Framework for Large-Scale
Measurement of Broadband Performance (LMAP)", <a href="./rfc7594">RFC 7594</a>,
DOI 10.17487/RFC7594, September 2015,
<<a href="https://www.rfc-editor.org/info/rfc7594">https://www.rfc-editor.org/info/rfc7594</a>>.
Acknowledgements
The authors thank Brian Carpenter for identifying the lack of IPv6
coverage in IPPM's framework and listing additional distinguishing
factors for packets of Type-P. Both Brian and Fred Baker discussed
many of the interesting aspects of IPv6 with the coauthors, leading
to a more solid first draft: thank you both. Thanks to Bill Jouris
for an editorial pass through the pre-00 text. As we completed our
journey, Nevil Brownlee, Mike Heard, Spencer Dawkins, Warren Kumari,
and Suresh Krishnan all contributed useful suggestions.
<span class="grey">Morton, et al. Informational [Page 14]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-15" ></span>
<span class="grey"><a href="./rfc8468">RFC 8468</a> IPPM IPv6 Update November 2018</span>
Authors' Addresses
Al Morton
AT&T Labs
200 Laurel Avenue South
Middletown, NJ 07748
United States of America
Phone: +1 732 420 1571
Fax: +1 732 368 1192
Email: acm@researh.att.com
Joachim Fabini
TU Wien
Gusshausstrasse 25/E389
Vienna 1040
Austria
Phone: +43 1 58801 38813
Fax: +43 1 58801 38898
Email: Joachim.Fabini@tuwien.ac.at
URI: <a href="http://www.tc.tuwien.ac.at/about-us/staff/joachim-fabini/">http://www.tc.tuwien.ac.at/about-us/staff/joachim-fabini/</a>
Nalini Elkins
Inside Products, Inc.
Carmel Valley, CA 93924
United States of America
Email: nalini.elkins@insidethestack.com
Michael S. Ackermann
Blue Cross Blue Shield of Michigan
Email: mackermann@bcbsm.com
Vinayak Hegde
Consultant
Brahma Sun City, Wadgaon-Sheri
Pune, Maharashtra 411014
India
Phone: +91 9449834401
Email: vinayakh@gmail.com
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Morton, et al. Informational [Page 15]
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