draft-ietf-ippm-2330-ipv6-00.txt   draft-ietf-ippm-2330-ipv6-01.txt 
Network Working Group A. Morton Network Working Group A. Morton
Internet-Draft AT&T Labs Internet-Draft AT&T Labs
Updates: 2330 (if approved) J. Fabini Updates: 2330 (if approved) J. Fabini
Intended status: Informational TU Wien Intended status: Informational TU Wien
Expires: January 5, 2017 N. Elkins Expires: September 7, 2017 N. Elkins
Inside Products, Inc. Inside Products, Inc.
M. Ackermann M. Ackermann
Blue Cross Blue Shield of Michigan Blue Cross Blue Shield of Michigan
V. Hegde V. Hegde
Consultant Consultant
July 04, 2016 March 6, 2017
IPv6 Updates for IPPM's Active Metric Framework IPv6 Updates for IPPM's Active Metric Framework
draft-ietf-ippm-2330-ipv6-00 draft-ietf-ippm-2330-ipv6-01
Abstract Abstract
This memo updates the IP Performance Metrics (IPPM) Framework RFC This memo updates the IP Performance Metrics (IPPM) Framework RFC
2330 with new considerations for measurement methodology and testing. 2330 with new considerations for measurement methodology and testing.
The memo updates the definition of standard-formed packets in RFC It updates the definition of standard-formed packets in RFC 2330 to
2330 to include IPv6 packets. It also augments distinguishing include IPv6 packets and augments distinguishing aspects of packets,
aspects of packets, referred to as Type-P for test packets in RFC referred to as Type-P for test packets in RFC 2330. This memo
2330. identifies that IPv4-IPv6 co-existence can challenge measurements
within the scope of the IPPM Framework. Exemplary use cases include,
Two points (at least) are worthwhile discussing further: extent of but are not limited to IPv4-IPv6 translation, NAT, protocol
coverage for 6LO and IPv6 Header Compression, and the continued need encapsulation, or IPv6 header compression.
to define a "minimal standard-formed packet".
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
skipping to change at page 2, line 6 skipping to change at page 2, line 4
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 7, 2017.
This Internet-Draft will expire on January 5, 2017.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Packets of Type-P . . . . . . . . . . . . . . . . . . . . . . 3 3. Packets of Type-P . . . . . . . . . . . . . . . . . . . . . . 3
4. Standard-Formed Packets . . . . . . . . . . . . . . . . . . . 5 4. Standard-Formed Packets . . . . . . . . . . . . . . . . . . . 5
5. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . 7 5. NAT, IPv4-IPv6 Transition and Compression Techniques . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7 6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
9.1. Normative References . . . . . . . . . . . . . . . . . . 8 9.1. Normative References . . . . . . . . . . . . . . . . . . 9
9.2. Informative References . . . . . . . . . . . . . . . . . 10 9.2. Informative References . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction 1. Introduction
The IETF IP Performance Metrics (IPPM) working group first created a The IETF IP Performance Metrics (IPPM) working group first created a
framework for metric development in [RFC2330]. This framework has framework for metric development in [RFC2330]. This framework has
stood the test of time and enabled development of many fundamental stood the test of time and enabled development of many fundamental
metrics. It has been updated in the area of metric composition metrics. It has been updated in the area of metric composition
[RFC5835], and in several areas related to active stream measurement [RFC5835], and in several areas related to active stream measurement
of modern networks with reactive properties [RFC7312]. of modern networks with reactive properties [RFC7312].
skipping to change at page 4, line 23 skipping to change at page 4, line 21
of the exact type of traffic being measured. of the exact type of traffic being measured.
If the information constituting Type-P at the Source is found to have If the information constituting Type-P at the Source is found to have
changed at the Destination (or at a measurement point between the changed at the Destination (or at a measurement point between the
Source and Destination, as in [RFC5644]), then the modified values Source and Destination, as in [RFC5644]), then the modified values
SHOULD be noted and reported with the results. Some modifications SHOULD be noted and reported with the results. Some modifications
occur according to the conditions encountered in transit (such as occur according to the conditions encountered in transit (such as
congestion notification) or due to the requirements of segments of congestion notification) or due to the requirements of segments of
the Source to Destination path. For example, the packet length will the Source to Destination path. For example, the packet length will
change if IP headers are converted to the alternate version/address change if IP headers are converted to the alternate version/address
family, or if optional Extension Headers are added or removed. Local family, or if optional Extension Headers are added or removed. Even
policies in intermediate nodes based on examination of IPv6 Extension header fields like TTL/Hop Limit that typically change in transit may
Headers may affect measurement repeatability. If intermediate nodes be relevant to specific tests. For example Neighbor Discovery
follow the recommendations of [RFC7045], repeatability may be Protocol (NDP) [RFC4861] packets are transmitted with Hop Limit value
improved to some degree. set to 255, and the validity test specifies that the Hop Limit 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.
A Network Address Translator (NAT) on the path can have unpredictable Local policies in intermediate nodes based on examination of IPv6
impact on latency measurement (in terms of the amount of additional Extension Headers may affect measurement repeatability. If
time added), and possibly other types of measurements. It is not intermediate nodes follow the recommendations of [RFC7045],
usually possible to control this impact (as testers may not have any repeatability may be improved to some degree.
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. 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.
A closely related note: it would be very useful to know if a given A closely related note: it would be very useful to know if a given
Internet component (like host, link, or path) treats equally a class Internet component (like host, link, or path) treats equally a class
C of different types of packets. If so, then any one of those types 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. of packets can be used for subsequent measurement of the component.
This suggests we devise a metric or suite of metrics that attempt to This suggests we devise a metric or suite of metrics that attempt to
determine C. determine C.
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 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 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. 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 therefore a prerequisite for
repeatable measurements. A path may have more than one stage of load
balancing, adding to class C definition complexity.
4. Standard-Formed Packets 4. Standard-Formed Packets
Unless otherwise stated, all metric definitions that concern IP Unless otherwise stated, all metric definitions that concern IP
packets include an implicit assumption that the packet is *standard- packets include an implicit assumption that the packet is *standard-
formed*. A packet is standard-formed if it meets all of the following formed*. A packet is standard-formed if it meets all of the following
criteria: criteria:
+ It includes a valid IP header: see below for version-specific + It includes a valid IP header: see below for version-specific
criteria. criteria.
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hop, or it possesses the maximum TTL of 255. hop, or it possesses the maximum TTL of 255.
o It does not contain IP options unless explicitly noted. o It does not contain IP options unless explicitly noted.
For an IPv6 ([RFC2460] and updates) packet to be standard-formed, the For an IPv6 ([RFC2460] and updates) packet to be standard-formed, the
following criteria are required: following criteria are required:
o The version field is 6. o The version field is 6.
o Its total length corresponds to the size of the IPv6 header (40 o Its total length corresponds to the size of the IPv6 header (40
octets) plus the length of the payload (including Extension octets) plus the length of the payload as given in the IPv6
Headers) as given in the IPv6 header. header.
o The payload length value for this packet (including Extension
Headers) conforms to the IPv6 specifications.
o Either the packet possesses sufficient Hop Count to travel from o Either the packet possesses sufficient Hop Count to travel from
the Source to the Destination if the Hop Count is decremented by the Source to the Destination if the Hop Count is decremented by
one at each hop, or it possesses the maximum Hop Count of 255. one at each hop, or it possesses the maximum Hop Count of 255.
o Either the packet does not contain IP Extension Headers, or it o Either the packet does not contain IP Extension Headers, or it
contains the correct number and type of headers as specified in contains the correct number and type of headers as specified in
the packet, and the headers appear in the standard-conforming the packet, and the headers appear in the standard-conforming
order (Next Header). order (Next Header).
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+ It contains no options or Extension Headers. + It contains no options or Extension Headers.
(Note that we do not define its protocol field, as different values (Note that we do not define its protocol field, as different values
may lead to different treatment by the network.) may lead to different treatment by the network.)
When defining IP metrics we keep in mind that no packet smaller or When defining IP metrics we keep in mind that no packet smaller or
simpler than this can be transmitted over a correctly operating IP simpler than this can be transmitted over a correctly operating IP
network. network.
5. Conclusions 5. NAT, IPv4-IPv6 Transition and Compression Techniques
This memo adds the key considerations for utilizing IPv6 in two This memo adds the key considerations for utilizing IPv6 in two
critical conventions of the IPPM Framework. It is RECOMMENDED to critical conventions of the IPPM Framework, namely packets of Type-P
adopt these new considerations in measurements involving IPv6. and standard-formed packets. The need for co-existence of IPv4 and
IPv6 has originated transitioning standards like the Framework for
IPv4/IPv6 Translation in [RFC6144] or IP/ICMP Translation Algorithms
in [RFC6145] and [RFC7757].
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 particular 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.
Exemplary consequences include, but are not limited to:
o Modification or addition of headers or header field values in
intermediate nodes. As noted in Section 4 for IPv6 extension
header manipulation, NAT, 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
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.
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 spend 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 inter-packet 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 the way how the measurement path treats the packets.
Points that are worthwhile discussing further: handling of large
packets in IPv6 (including fragment extension headers, PMTUD,
PLMTUD), extent of coverage for 6LO and IPv6 Header Compression, and
the continued need to define a "minimal standard-formed packet".
.
6. Security Considerations 6. Security Considerations
The security considerations that apply to any active measurement of The security considerations that apply to any active measurement of
live paths are relevant here as well. See [RFC4656] and [RFC5357]. live paths are relevant here as well. See [RFC4656] and [RFC5357].
When considering privacy of those involved in measurement or those When considering privacy of those involved in measurement or those
whose traffic is measured, the sensitive information available to whose traffic is measured, the sensitive information available to
potential observers is greatly reduced when using active techniques potential observers is greatly reduced when using active techniques
which are within this scope of work. Passive observations of user which are within this scope of work. Passive observations of user
skipping to change at page 9, line 15 skipping to change at page 10, line 43
[RFC4494] Song, JH., Poovendran, R., and J. Lee, "The AES-CMAC-96 [RFC4494] Song, JH., Poovendran, R., and J. Lee, "The AES-CMAC-96
Algorithm and Its Use with IPsec", RFC 4494, Algorithm and Its Use with IPsec", RFC 4494,
DOI 10.17487/RFC4494, June 2006, DOI 10.17487/RFC4494, June 2006,
<http://www.rfc-editor.org/info/rfc4494>. <http://www.rfc-editor.org/info/rfc4494>.
[RFC4656] Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and M. [RFC4656] Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and M.
Zekauskas, "A One-way Active Measurement Protocol Zekauskas, "A One-way Active Measurement Protocol
(OWAMP)", RFC 4656, DOI 10.17487/RFC4656, September 2006, (OWAMP)", RFC 4656, DOI 10.17487/RFC4656, September 2006,
<http://www.rfc-editor.org/info/rfc4656>. <http://www.rfc-editor.org/info/rfc4656>.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007,
<http://www.rfc-editor.org/info/rfc4861>.
[RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J. [RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J.
Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)", Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)",
RFC 5357, DOI 10.17487/RFC5357, October 2008, RFC 5357, DOI 10.17487/RFC5357, October 2008,
<http://www.rfc-editor.org/info/rfc5357>. <http://www.rfc-editor.org/info/rfc5357>.
[RFC5644] Stephan, E., Liang, L., and A. Morton, "IP Performance [RFC5644] Stephan, E., Liang, L., and A. Morton, "IP Performance
Metrics (IPPM): Spatial and Multicast", RFC 5644, Metrics (IPPM): Spatial and Multicast", RFC 5644,
DOI 10.17487/RFC5644, October 2009, DOI 10.17487/RFC5644, October 2009,
<http://www.rfc-editor.org/info/rfc5644>. <http://www.rfc-editor.org/info/rfc5644>.
[RFC5835] Morton, A., Ed. and S. Van den Berghe, Ed., "Framework for [RFC5835] Morton, A., Ed. and S. Van den Berghe, Ed., "Framework for
Metric Composition", RFC 5835, DOI 10.17487/RFC5835, April Metric Composition", RFC 5835, DOI 10.17487/RFC5835, April
2010, <http://www.rfc-editor.org/info/rfc5835>. 2010, <http://www.rfc-editor.org/info/rfc5835>.
[RFC6144] Baker, F., Li, X., Bao, C., and K. Yin, "Framework for
IPv4/IPv6 Translation", RFC 6144, DOI 10.17487/RFC6144,
April 2011, <http://www.rfc-editor.org/info/rfc6144>.
[RFC6145] Li, X., Bao, C., and F. Baker, "IP/ICMP Translation
Algorithm", RFC 6145, DOI 10.17487/RFC6145, April 2011,
<http://www.rfc-editor.org/info/rfc6145>.
[RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6 [RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6
Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
DOI 10.17487/RFC6282, September 2011, DOI 10.17487/RFC6282, September 2011,
<http://www.rfc-editor.org/info/rfc6282>. <http://www.rfc-editor.org/info/rfc6282>.
[RFC6437] Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme, [RFC6437] Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme,
"IPv6 Flow Label Specification", RFC 6437, "IPv6 Flow Label Specification", RFC 6437,
DOI 10.17487/RFC6437, November 2011, DOI 10.17487/RFC6437, November 2011,
<http://www.rfc-editor.org/info/rfc6437>. <http://www.rfc-editor.org/info/rfc6437>.
skipping to change at page 10, line 5 skipping to change at page 11, line 47
[RFC7045] Carpenter, B. and S. Jiang, "Transmission and Processing [RFC7045] Carpenter, B. and S. Jiang, "Transmission and Processing
of IPv6 Extension Headers", RFC 7045, of IPv6 Extension Headers", RFC 7045,
DOI 10.17487/RFC7045, December 2013, DOI 10.17487/RFC7045, December 2013,
<http://www.rfc-editor.org/info/rfc7045>. <http://www.rfc-editor.org/info/rfc7045>.
[RFC7312] Fabini, J. and A. Morton, "Advanced Stream and Sampling [RFC7312] Fabini, J. and A. Morton, "Advanced Stream and Sampling
Framework for IP Performance Metrics (IPPM)", RFC 7312, Framework for IP Performance Metrics (IPPM)", RFC 7312,
DOI 10.17487/RFC7312, August 2014, DOI 10.17487/RFC7312, August 2014,
<http://www.rfc-editor.org/info/rfc7312>. <http://www.rfc-editor.org/info/rfc7312>.
[RFC7757] Anderson, T. and A. Leiva Popper, "Explicit Address
Mappings for Stateless IP/ICMP Translation", RFC 7757,
DOI 10.17487/RFC7757, February 2016,
<http://www.rfc-editor.org/info/rfc7757>.
9.2. Informative References 9.2. Informative References
[RFC7594] Eardley, P., Morton, A., Bagnulo, M., Burbridge, T., [RFC7594] Eardley, P., Morton, A., Bagnulo, M., Burbridge, T.,
Aitken, P., and A. Akhter, "A Framework for Large-Scale Aitken, P., and A. Akhter, "A Framework for Large-Scale
Measurement of Broadband Performance (LMAP)", RFC 7594, Measurement of Broadband Performance (LMAP)", RFC 7594,
DOI 10.17487/RFC7594, September 2015, DOI 10.17487/RFC7594, September 2015,
<http://www.rfc-editor.org/info/rfc7594>. <http://www.rfc-editor.org/info/rfc7594>.
Authors' Addresses Authors' Addresses
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