Internet DRAFT - draft-vyncke-v6ops-james
draft-vyncke-v6ops-james
IPv6 Operations É. Vyncke
Internet-Draft Cisco
Intended status: Informational R. Léas
Expires: 13 July 2023 J. Iurman
Université de Liège
9 January 2023
Just Another Measurement of Extension header Survivability (JAMES)
draft-vyncke-v6ops-james-03
Abstract
In 2016, RFC7872 has measured the drop of packets with IPv6 extension
headers. This document presents a slightly different methodology
with more recent results. It is still work in progress.
About This Document
This note is to be removed before publishing as an RFC.
The latest revision of this draft can be found at
https://evyncke.github.io/v6ops-james/draft-vyncke-v6ops-james.html.
Status information for this document may be found at
https://datatracker.ietf.org/doc/draft-vyncke-v6ops-james/.
Discussion of this document takes place on the IPv6 Operations
Working Group mailing list (mailto:v6ops@ietf.org), which is archived
at https://mailarchive.ietf.org/arch/browse/v6ops/.
Source for this draft and an issue tracker can be found at
https://github.com/evyncke/v6ops-james.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
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This Internet-Draft will expire on 13 July 2023.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) 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
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Methodology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Measurements . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Vantage Points . . . . . . . . . . . . . . . . . . . . . 3
3.2. Tested Autonomous Systems . . . . . . . . . . . . . . . . 5
3.2.1. Drop attribution to AS . . . . . . . . . . . . . . . 7
3.3. Tested Extension Headers . . . . . . . . . . . . . . . . 8
4. Results . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.1. Routing Header . . . . . . . . . . . . . . . . . . . . . 10
4.2. Hop-by-Hop Options Header . . . . . . . . . . . . . . . . 13
4.3. Destination Options Header . . . . . . . . . . . . . . . 13
4.4. Fragmentation Header . . . . . . . . . . . . . . . . . . 15
4.5. No extension headers drop at all . . . . . . . . . . . . 15
4.6. Other Next Headers . . . . . . . . . . . . . . . . . . . 16
5. Summary of the collaborating parties measurements . . . . . . 17
6. Security Considerations . . . . . . . . . . . . . . . . . . . 17
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 17
8.1. Normative References . . . . . . . . . . . . . . . . . . 17
8.2. Informative References . . . . . . . . . . . . . . . . . 18
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20
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1. Introduction
In 2016, [RFC7872] has measured the drop of packets with IPv6
extension headers on their transit over the global Internet. This
document presents a slightly different methodology with more recent
results. Since then, [I-D.draft-ietf-opsec-ipv6-eh-filtering] has
provided some recommendations for filtering transit traffic, so there
may be some changes in providers policies. Also, [RFC9098] raises
awareness about the operational and security implications of IPv6
extension headers and present reasons why some networks would drop
them intentionally.
It is still work in progress, but the authors wanted to present some
results at IETF-113 (March 2022). The code is open source and is
available at [GITHUB].
2. Methodology
In a first phase, the measurement is done between collaborating IPv6
nodes, a.k.a. vantage points, spread over the Internet and multiple
Autonomous Systems (ASs). As seen in Section 3.2, the
source/destination/transit ASs include some "tier-1" providers per
[TIER1], so, they are probably representative of the global Internet
core.
Relying on collaborating nodes has some benefits:
* propagation can be measured even in the absence of any ICMP
message or reply generated by the destination;
* traffic timing can be measured accurately to answer whether
extension headers are slower than plain IPv6 packets;
* traffic can be captured into .pcap [I-D.draft-ietf-opsawg-pcap]
file at the source and at the destination for later analysis.
Future phases will send probes to non-collaborating nodes with a much
reduced probing speed. The destination will include [ALEXA] top-n
websites, popular CDN, as well as random prefix from the IPv6 global
routing table. A revision of this IETF draft will describe those
experiments.
3. Measurements
3.1. Vantage Points
Several servers were used worldwide. Table 1 lists all the vantage
points together with their AS number and country.
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+========+===================+==============+===================+
| ASN | AS Name | Country code | Location |
+========+===================+==============+===================+
| 267 | NETHER-NET | US | Southfield, MI |
+--------+-------------------+--------------+-------------------+
| 3764 | AFRINIC-Ops | ZA | Johanesburg |
+--------+-------------------+--------------+-------------------+
| 4134 | Chine Telecom | CN | Beijing |
+--------+-------------------+--------------+-------------------+
| 7195 | Edge Uno | AR | Buenos Aires |
+--------+-------------------+--------------+-------------------+
| 12414 | NL-SOLCON SOLCON | NL | Amsterdam |
+--------+-------------------+--------------+-------------------+
| 14061 | Digital Ocean | CA | Toronto, ON |
+--------+-------------------+--------------+-------------------+
| 14061 | Digital Ocean | USA | New York City, NY |
+--------+-------------------+--------------+-------------------+
| 14601 | Digital Ocean | DE | Francfort |
+--------+-------------------+--------------+-------------------+
| 14601 | Digital Ocean | IN | Bangalore |
+--------+-------------------+--------------+-------------------+
| 14601 | Digital Ocean | SG | Singapore |
+--------+-------------------+--------------+-------------------+
| 14601 | Digital Ocean | UK | London |
+--------+-------------------+--------------+-------------------+
| 16276 | OVH | AU | Sydney |
+--------+-------------------+--------------+-------------------+
| 16276 | OVH | PL | Warsaw |
+--------+-------------------+--------------+-------------------+
| 20473 | The Constant | MX | Mexico |
| | Company (Vultr) | | |
+--------+-------------------+--------------+-------------------+
| 20473 | The Constant | SP | Madrid |
| | Company (Vultr) | | |
+--------+-------------------+--------------+-------------------+
| 20473 | The Constant | JP | Tokyo |
| | Company (Vultr) | | |
+--------+-------------------+--------------+-------------------+
| 37684 | Angani | KE | Nairobi |
+--------+-------------------+--------------+-------------------+
| 37708 | AfriNIC Corporate | MU | Ebene |
| | Network | | |
+--------+-------------------+--------------+-------------------+
| 44684 | Mythic Beasts | UK | Cambridge |
+--------+-------------------+--------------+-------------------+
| 60011 | MYTHIC-BEASTS-USA | US | Fremont, CA |
+--------+-------------------+--------------+-------------------+
| 198644 | GO6 | SI | Ljubljana |
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+--------+-------------------+--------------+-------------------+
Table 1: All vantage AS
3.2. Tested Autonomous Systems
During first phase (traffic among fully-meshed collaborative nodes),
Table 2 show the ASs for which our probes have collected data.
+===========+=========================================+==========+
| AS Number | AS Description | Comment |
+===========+=========================================+==========+
| 174 | COGENT-174, US | Tier-1 |
+-----------+-----------------------------------------+----------+
| 267 | NETHER-NET, US | |
+-----------+-----------------------------------------+----------+
| 1299 | TWELVE99 Arelion, fka Telia Carrier, SE | Tier-1 |
+-----------+-----------------------------------------+----------+
| 2497 | IIJ Internet Initiative Japan Inc., JP | |
+-----------+-----------------------------------------+----------+
| 2828 | XO-AS15, US | Regional |
| | | Tier |
+-----------+-----------------------------------------+----------+
| 2914 | NTT-LTD-2914, US | Tier-1 |
+-----------+-----------------------------------------+----------+
| 3257 | GTT-BACKBONE GTT, US | Tier-1 |
+-----------+-----------------------------------------+----------+
| 3320 | DTAG Internet service provider | Tier-1 |
| | operations, DE | |
+-----------+-----------------------------------------+----------+
| 3356 | LEVEL3, US | Tier-1 |
+-----------+-----------------------------------------+----------+
| 3491 | BTN-ASN, US | Tier-1 |
+-----------+-----------------------------------------+----------+
| 4134 | CHINANET-BACKBONE No.31,Jin-rong | Regional |
| | Street, CN | Tier |
+-----------+-----------------------------------------+----------+
| 4637 | ASN-TELSTRA-GLOBAL Telstra Global, HK | Regional |
| | | Tier |
+-----------+-----------------------------------------+----------+
| 4755 | TATACOMM-AS TATA Communications | |
| | formerly VSNL is Leading ISP, IN | |
+-----------+-----------------------------------------+----------+
| 4788 | TMNET-AS-AP TM Net, Internet Service | |
| | Provider, MY | |
+-----------+-----------------------------------------+----------+
| 5511 | OPENTRANSIT, FR | Tier-1 |
+-----------+-----------------------------------------+----------+
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| 5603 | SIOL-NET Telekom Slovenije d.d., SI | |
+-----------+-----------------------------------------+----------+
| 6453 | AS6453, US | Tier-1 |
+-----------+-----------------------------------------+----------+
| 6461 | ZAYO-6461 | Tier-1 |
+-----------+-----------------------------------------+----------+
| 6762 | SEABONE-NET TELECOM ITALIA SPARKLE | Tier-1 |
| | S.p.A., IT | |
+-----------+-----------------------------------------+----------+
| 6895 | ESPANIX Neutral Interconect Exchange | |
| | for Spain, ES | |
+-----------+-----------------------------------------+----------+
| 6939 | HURRICANE, US | Regional |
| | | Tier |
+-----------+-----------------------------------------+----------+
| 7195 | EDGEUNO SAS, CO | |
+-----------+-----------------------------------------+----------+
| 8447 | A1TELEKOM-AT A1 Telekom Austria AG, AT | |
+-----------+-----------------------------------------+----------+
| 9498 | BBIL-AP BHARTI Airtel Ltd., IN | |
+-----------+-----------------------------------------+----------+
| 12129 | 123NET, US | |
+-----------+-----------------------------------------+----------+
| 12414 | NL-SOLCON SOLCON, NL | |
+-----------+-----------------------------------------+----------+
| 14061 | DIGITALOCEAN-ASN, US | |
+-----------+-----------------------------------------+----------+
| 14103 | ACDNET-ASN1, US | |
+-----------+-----------------------------------------+----------+
| 16276 | OVH, FR | |
+-----------+-----------------------------------------+----------+
| 20473 | AS-CHOOPA, US | |
+-----------+-----------------------------------------+----------+
| 21283 | A1SI-AS A1 Slovenija, SI | |
+-----------+-----------------------------------------+----------+
| 23889 | MauritiusTelecom, MU | |
+-----------+-----------------------------------------+----------+
| 33764 | AFRINIC-ZA-JNB-AS, MU | |
+-----------+-----------------------------------------+----------+
| 34779 | T-2-AS AS set propagated by T-2 d.o.o., | |
| | SI | |
+-----------+-----------------------------------------+----------+
| 37100 | SEACOM-AS, MU | |
+-----------+-----------------------------------------+----------+
| 37271 | Workonline | |
+-----------+-----------------------------------------+----------+
| 37684 | ANGANI-AS, KE | |
+-----------+-----------------------------------------+----------+
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| 37708 | AFRINIC-MAIN, MU | |
+-----------+-----------------------------------------+----------+
| 44684 | MYTHIC Mythic Beasts Ltd, GB | |
+-----------+-----------------------------------------+----------+
| 58461 | CT-HANGZHOU-IDC No.288,Fu-chun Road, CN | |
+-----------+-----------------------------------------+----------+
| 60011 | MYTHIC-BEASTS-USA, GB | |
+-----------+-----------------------------------------+----------+
| 198644 | GO6, SI | |
+-----------+-----------------------------------------+----------+
| 211722 | Nullroute | |
+-----------+-----------------------------------------+----------+
| 328578 | KEMNET-TECHNOLOGIES-AS, KE | |
+-----------+-----------------------------------------+----------+
Table 2: All AS (source/destination/transit)
The table attributes some tier qualification to some ASs based on the
Wikipedia page [TIER1], but there is no common way to decide who is a
tier-1. Based on some CAIDA research, all the above (except GO6,
which is a stub network) are transit providers.
While this document lists some operators, the intent is not to build
a wall of fame or a wall of shame but more to get an idea about which
kind of providers drop packets with extension headers and how
widespread the drop policy is enforced and where, i.e., in the access
provider or in the core of the Internet.
3.2.1. Drop attribution to AS
Comparing the traceroutes with and without extension headers allows
the attribution of a packet drop to one AS. But, this is not an easy
task as inter-AS links often use IPv6 address of only one AS (if not
using link-local per [RFC7404]). This document uses the following
algorithm to attribute the drop to one AS for packet sourced in one
AS and then having a path traversing AS#foo just before AS#bar:
* if the packet drop happens at the first router (i.e., hop limit ==
1 does not trigger an ICMP hop-limit exceeded), then the drop is
assumed to this AS as it is probably an ingress filter on the
first router (i.e., the hosting provider in most of the cases -
except if collocated with an IXP).
* if the packet drop happens in AS#foo after one or more hop(s) in
AS#bar, then the drop is assumed to be in AS#foo ingress filter on
a router with an interface address in AS#foo
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* if the packet drop happens in AS#bar after one or more hop(s) in
AS#bar before going to AS#foo, then the drop is assumed to be in
AS#foo ingress filter on a router with an interface address in
AS#bar
In several cases, the above algorithm was not possible (e.g., some
intermediate routers do not generate an ICMP unreachable hop limit
exceeded even in the absence of any extension headers), then the drop
is not attributed. Please also note that the goal of this document
is not to 'point fingers to operators' but more to evaluate the
potential impact. I.e., a tier-1 provider dropping packets with
extension headers has a much bigger impact on the Internet traffic
than an access provider.
Future revision of this document will use the work of [MLAT_PEERING].
Readers are urged not to rely on the AS attribution in this document
version.
3.3. Tested Extension Headers
In the first phase among collaborating vantage points, packets always
contained either a UDP payload or a TCP payload, the latter is sent
with only the SYN flag set and with data as permitted by section 3.4
of [RFC793] (2nd paragraph). A usual traceroute is done with only
the UDP/TCP payload without any extension header with varying hop-
limit in order to learn the traversed routers and ASs. Then, several
UDP/TCP probes are sent with a set of extension headers:
* hop-by-hop options header containing:
- one PadN option for a length of 8 octets
- one unknown option with the "discard" bits for a length of 8
octets
- one unknown option (two sets: with "discard" and "skip" bits)
for a length of 256 and 512 octets
* destination options header containing:
- one PadN option for a length of 8 octets
- one unknown option with the "discard" bits for a length of 8
octets
- one unknown option (two sets: with "discard" and "skip" bits)
for a length of 16, 32, 64, 128, 256, and 512 octets
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- one unknown option (with "skip" bits) for a length of 24, 40,
48, and 56 octets
* routing header with routing types from 0 to 6 inclusive
* fragment header of varying frame length 512, 1280, and 1500
octets:
- atomic fragment (i.e., M-flag = 0 and offset = 0)
- non-atomic first fragment (i.e., M-flag = 1 and offset = 0)
* encapsulation security payload (ESP) header with dummy SPI
followed by UDP/TCP header and a 38 octets payload
* authentication header (AH) with dummy SPI followed by UDP/TCP
header and a 38 octets payload
In the above, length is the length of the extension header itself
except for the fragmentation header where the length is the IP packet
length (i.e., including the IPv6, and TCP/UDP headers + payload).
Also, an unknown option means an option with an unassigned code in
the IANA registry [IANA_IPV6_PARAMS].
For hop-by-hop and destination options headers, the choice was made
to use one unknown option instead of multiple consecutive PadN
options in order to avoid packets from being discarded on the
destination. Indeed, the Linux kernel does not accept consecutive
Pad1 or PadN options if their total size exceeds 7 octets. Not only
multiple PadN options violate section 2.1.9.5 of [RFC4942], but it is
also considered as suspicious (see section 5.3 of [BCP220]).
Nevertheless, for comparative purposes, multiple PadN options were
used for experiments of length 256 octets. In that very specific
case, drops on the destination are not considered as drops.
In addition to the above extension headers, other probes were sent
with next header field of IPv6 header set to:
* 59, which is "no next header", especially whether extra octets
after the no next header as section 4.7 [RFC8200] requires that
"those octets must be ignored and passed on unchanged if the
packet is forwarded"
* 143, which is Ethernet payload (see section 10.1 of [RFC8986])
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4. Results
This section presents the current results out of phase 1
(collaborating vantage points) testing. Probe packets were sent
between all pairs of vantage points with a hop-limit from 1 to the
number of hops between the two vantage points and for all the
extension headers described in Section 3.3.
4.1. Routing Header
Table 3 lists all routing header types and the percentage of
experiments that were successful, i.e., packets with routing header
reaching their destination, both for UDP and TCP:
+=====================+=======+=======+
| Routing Header Type | UDP | TCP |
+=====================+=======+=======+
| 0 | 74.3% | 71.2% |
+---------------------+-------+-------+
| 1 | 88.3% | 81.4% |
+---------------------+-------+-------+
| 2 | 97.4% | 90.4% |
+---------------------+-------+-------+
| 3 | 97.6% | 91.3% |
+---------------------+-------+-------+
| 4 | 78.8% | 72.6% |
+---------------------+-------+-------+
| 5 | 97.4% | 90.9% |
+---------------------+-------+-------+
| 6 | 97.4% | 90.0% |
+---------------------+-------+-------+
Table 3: Per Routing Header Types
Transmission
Table 4 and Table 5 respectively list ASs that drop packets with the
routing header type 0 (the original source routing header, which is
now deprecated) and packets with the routing header type 1 (NIMROD
[RFC1753], which is now deprecated).
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+===========+====================================================+
| AS Number | AS description |
+===========+====================================================+
| 1299 | TWELVE99 Arelion, fka Telia Carrier, SE |
+-----------+----------------------------------------------------+
| 5511 | OPENTRANSIT, FR |
+-----------+----------------------------------------------------+
| 6895 | ESPANIX Neutral Interconect Exchange for Spain, ES |
+-----------+----------------------------------------------------+
| 6939 | HURRICANE, US |
+-----------+----------------------------------------------------+
| 7195 | EDGEUNO (DE-CIX Frankfurt) |
+-----------+----------------------------------------------------+
| 9498 | BBIL-AP BHARTI Airtel Ltd. (Equinix Hong Kong) |
+-----------+----------------------------------------------------+
| 14061 | DIGITALOCEAN (DE-CIX Frankfurt) |
+-----------+----------------------------------------------------+
| 16276 | OVH |
+-----------+----------------------------------------------------+
| 37684 | ANGANI-AS, KE |
+-----------+----------------------------------------------------+
| 58461 | CT-HANGZHOU-IDC No.288,Fu-chun Road, CN |
+-----------+----------------------------------------------------+
| 328578 | KEMNET-TECHNOLOGIES-AS, KE |
+-----------+----------------------------------------------------+
Table 4: ASs dropping Routing Header Type 0
+===========+=============================================+
| AS Number | AS description |
+===========+=============================================+
| 1299 | TWELVE99 Arelion, fka Telia Carrier, SE |
+-----------+---------------------------------------------+
| 4134 | CHINANET-BACKBONE No.31,Jin-rong Street, CN |
+-----------+---------------------------------------------+
| 5511 | OPENTRANSIT, FR |
+-----------+---------------------------------------------+
| 37684 | ANGANI-AS, KE |
+-----------+---------------------------------------------+
| 58461 | CT-HANGZHOU-IDC No.288,Fu-chun Road, CN |
+-----------+---------------------------------------------+
| 328578 | KEMNET-TECHNOLOGIES-AS, KE |
+-----------+---------------------------------------------+
Table 5: ASs dropping Routing Header Type 1
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Regarding the routing type 0, it is possibly due to a strict
implementation of [RFC5095] but it is expected that no packet with
such routing type would be transmitted anymore. So, this is not
surprising. The same reasoning could be applied to the routing type
1.
Table 6 lists ASs that drop packets with the routing header type 4
(Segment Routing Header [RFC8754]).
+===========+=========================================+
| AS Number | AS description |
+===========+=========================================+
| 1299 | TWELVE99 Arelion, fka Telia Carrier, SE |
+-----------+-----------------------------------------+
| 4637 | ASN-TELSTRA-GLOBAL Telstra Global, HK |
+-----------+-----------------------------------------+
| 5511 | OPENTRANSIT, FR |
+-----------+-----------------------------------------+
| 6939 | HURRICANE, US |
+-----------+-----------------------------------------+
| 7195 | EDGEUNO SAS, CO |
+-----------+-----------------------------------------+
| 14061 | DIGITALOCEAN-ASN, US |
+-----------+-----------------------------------------+
| 16276 | OVH, FR |
+-----------+-----------------------------------------+
| 37100 | SEACOM-AS, MU |
+-----------+-----------------------------------------+
| 58461 | CT-HANGZHOU-IDC No.288,Fu-chun Road, CN |
+-----------+-----------------------------------------+
Table 6: ASs dropping Routing Header Type 4
This drop of SRH was to be expected as SRv6 is specified to run only
in a limited domain.
Other routing header types (2 == mobile IPv6 [RFC6275], 3 == RPL
[RFC6554], and even 5 == CRH-16 and 6 == CRH-
32[I-D.draft-bonica-6man-comp-rtg-hdr]) can be transmitted over the
global Internet without being dropped (assuming that the 2.5% of
dropped packets are within the measurement error). At least, this is
true for UDP. We still need to investigate the differences for TCP
equivalent transmissions.
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4.2. Hop-by-Hop Options Header
Table 7 lists all experiments (types and lengths) along with their
success percentages, i.e., packets with a hop-by-hop header reaching
their destination, both for UDP and TCP:
+==============+================+======+======+
| Option Type | Length (bytes) | UDP | TCP |
+==============+================+======+======+
| Skip | 8 | 8.6% | 9.1% |
+--------------+----------------+------+------+
| Discard | 8 | 0.0% | 0.0% |
+--------------+----------------+------+------+
| Skip | 256 | 2.4% | 2.4% |
+--------------+----------------+------+------+
| Skip w/ PadN | 256 | 0.5% | 0.6% |
+--------------+----------------+------+------+
| Discard | 256 | 0.0% | 0.0% |
+--------------+----------------+------+------+
| Skip | 512 | 1.4% | 1.5% |
+--------------+----------------+------+------+
| Discard | 512 | 0.0% | 0.0% |
+--------------+----------------+------+------+
Table 7: Hop-by-hop Header Transmission
It appears that hop-by-hop options headers cannot reliably traverse
the global Internet; only small headers with 'skipable' options have
some chances. If the unknown hop-by-hop option has the 'discard'
bits, it is dropped per specification, although we observed in some
cases that such packets were not necessarily dropped directly by the
very first hop. Globally, there are no notable differences between
UDP and TCP.
4.3. Destination Options Header
Table 8 lists all lengths that have been tested along with their
success percentages, i.e., packets with a destination header reaching
their destination, both for UDP and TCP:
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+================+=======+=======+
| Length (bytes) | UDP | TCP |
+================+=======+=======+
| 8 | 97.8% | 94.3% |
+----------------+-------+-------+
| 16 | 97.7% | 90.5% |
+----------------+-------+-------+
| 24 | 97.6% | 89.8% |
+----------------+-------+-------+
| 32 | 93.5% | 86.2% |
+----------------+-------+-------+
| 40 | 93.9% | 86.2% |
+----------------+-------+-------+
| 48 | 93.7% | 86.1% |
+----------------+-------+-------+
| 56 | 93.8% | 52.7% |
+----------------+-------+-------+
| 64 | 45.9% | 37.8% |
+----------------+-------+-------+
| 128 | 10.9% | 10.9% |
+----------------+-------+-------+
| 256 | 4.3% | 4.3% |
+----------------+-------+-------+
| 256 w/ PadN | 4.3% | 4.3% |
+----------------+-------+-------+
| 512 | 3.1% | 3.1% |
+----------------+-------+-------+
Table 8: Destination Header
Transmission
The measurement revealed no difference with the discard bits, which
tends to show that routers do not look inside the destination header,
as expected.
The size of the destination options header has a major impact on the
drop probability. It appears that destination headers larger than 24
octets already cause drops. It may be because the 40 octets of the
IPv6 header + the 24 octets of the extension header (total 64 octets)
is still in the limits of some router hardware lookup mechanisms
while the next measured size (extension header size of 32 octets for
a total of 72 octets) is beyond the hardware limit and some ASs have
a policy to drop packets where the TCP/UDP ports are unknown. A
major drop also occurs once the size reaches 64 bytes for UDP while,
surprisingly, it happens at 56 bytes for TCP. In either case, the
chances of surviving are approximately halved. We still need to
investigate the differences for TCP equivalent transmissions.
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4.4. Fragmentation Header
The propagation of two kinds of fragmentation headers was analysed:
atomic fragment (offset == 0 and M-flag == 0) and plain first
fragment (offset == 0 and M-flag == 1). The Table 9 displays the
propagation differences.
+============+=======+=======+
| M-flag | UDP | TCP |
+============+=======+=======+
| 0 (atomic) | 55.8% | 49.8% |
+------------+-------+-------+
| 1 | 89.2% | 87.6% |
+------------+-------+-------+
Table 9: IPv6 Fragments
Transmission
The size of the overall IPv6 packets (512, 1280, and 1500 octets) has
no major impact on the propagation.
4.5. No extension headers drop at all
Table 10 lists ASs that do not drop transit traffic with extension
headers and therefore follow the recommendations of
[I-D.draft-ietf-opsec-ipv6-eh-filtering]:
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+===========+========================================+
| AS Number | AS Description |
+===========+========================================+
| 267 | NETHER-NET, US |
+-----------+----------------------------------------+
| 2497 | IIJ Internet Initiative Japan Inc., JP |
+-----------+----------------------------------------+
| 14103 | ACDNET-ASN1, US |
+-----------+----------------------------------------+
| 21283 | A1SI-AS A1 Slovenija, SI |
+-----------+----------------------------------------+
| 33764 | AFRINIC-ZA-JNB-AS, MU |
+-----------+----------------------------------------+
| 37271 | Workonline |
+-----------+----------------------------------------+
| 37708 | AFRINIC-MAIN, MU |
+-----------+----------------------------------------+
| 60011 | MYTHIC-BEASTS-USA, GB |
+-----------+----------------------------------------+
| 198644 | GO6, SI |
+-----------+----------------------------------------+
Table 10: ASs not dropping packets with Extension
Headers
4.6. Other Next Headers
Measurements also include two protocol numbers that are mainly new
use of IPv6 as well as AH and ESP. Table 11 indicates the percentage
of packets reaching the destination.
+=====================+==============+
| Next Header | Transmission |
+=====================+==============+
| NoNextHeader (59) | 98.2% |
+---------------------+--------------+
| Ethernet (143) | 98.3% |
+---------------------+--------------+
| Authentication (AH) | 98.1% |
+---------------------+--------------+
| ESP | 98.3% |
+---------------------+--------------+
Table 11: Transmission of Special
IP Protocols
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The above indicates that those IP protocols can be transmitted over
the global Internet without being dropped (assuming that the 2% of
dropped packets are within the measurement error). Globally, there
are no notable differences between UDP and TCP, for cases where it
applies.
5. Summary of the collaborating parties measurements
While the analysis has areas of improvement (geographical
distribution and impact on latency), it appears that:
* AH, ESP, and non-atomic fragmentation headers (to some extent) can
traverse the Internet;
* only routing headers types 0, 1 and 4 experiment problems over the
Internet, other types have no problems;
* hop-by-hop options headers do not traverse the Internet, whatever
the size;
* destination options headers are not reliable enough when it
exceeds 24 octets.
Of course, the next phase of measurement with non-collaborating
parties will probably give another view.
6. Security Considerations
While active probing of the Internet may be considered as an attack,
this measurement was done among collaborating parties and using the
probe attribution technique described in
[I-D.draft-vyncke-opsec-probe-attribution] to allow external parties
to identify the source of the probes if required.
7. IANA Considerations
This document has no IANA actions.
8. References
8.1. Normative References
[IANA_IPV6_PARAMS]
"Internet Protocol Version 6 (IPv6) Parameters,
Destination Options and Hop-by-Hop Options", n.d.,
<https://www.iana.org/assignments/ipv6-parameters/
ipv6-parameters.xhtml#ipv6-parameters-2>.
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[RFC793] Postel, J., "Transmission Control Protocol", RFC 793,
DOI 10.17487/RFC0793, September 1981,
<https://doi.org/10.17487/RFC0793>.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://doi.org/10.17487/RFC8200>.
8.2. Informative References
[ALEXA] "The top 500 sites on the web", n.d.,
<https://www.alexa.com/topsites>.
[BCP220] Chown, T., Loughney, J., and T. Winters, "IPv6 Node
Requirements", BCP 220, RFC 8504, January 2019.
<https://www.rfc-editor.org/info/bcp220>
[GITHUB] Léas, R., "james", n.d.,
<https://gitlab.uliege.be/Benoit.Donnet/james>.
[I-D.draft-bonica-6man-comp-rtg-hdr]
Bonica, R., Kamite, Y., Alston, A., Henriques, D., and L.
Jalil, "The IPv6 Compact Routing Header (CRH)", Work in
Progress, Internet-Draft, draft-bonica-6man-comp-rtg-hdr-
29, 14 November 2022,
<https://datatracker.ietf.org/doc/html/draft-bonica-6man-
comp-rtg-hdr-29>.
[I-D.draft-ietf-opsawg-pcap]
Harris, G. and M. Richardson, "PCAP Capture File Format",
Work in Progress, Internet-Draft, draft-ietf-opsawg-pcap-
01, 29 July 2022, <https://datatracker.ietf.org/doc/html/
draft-ietf-opsawg-pcap-01>.
[I-D.draft-ietf-opsec-ipv6-eh-filtering]
Gont, F. and W. S. LIU, "Recommendations on the Filtering
of IPv6 Packets Containing IPv6 Extension Headers at
Transit Routers", Work in Progress, Internet-Draft, draft-
ietf-opsec-ipv6-eh-filtering-10, 3 May 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-opsec-
ipv6-eh-filtering-10>.
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[I-D.draft-vyncke-opsec-probe-attribution]
Vyncke, E., Donnet, B., and J. Iurman, "Attribution of
Internet Probes", Work in Progress, Internet-Draft, draft-
vyncke-opsec-probe-attribution-01, 3 March 2022,
<https://datatracker.ietf.org/doc/html/draft-vyncke-opsec-
probe-attribution-01>.
[MLAT_PEERING]
Giotsas, V., Zhou, S., Luckie, M., and K. Claffy,
"Inferring Multilateral Peering",
DOI 10.1145/2535372.2535390, December 2013,
<https://catalog.caida.org/details/
paper/2013_inferring_multilateral_peering/>.
[RFC1753] Chiappa, N., "IPng Technical Requirements Of the Nimrod
Routing and Addressing Architecture", RFC 1753,
DOI 10.17487/RFC1753, December 1994,
<https://doi.org/10.17487/RFC1753>.
[RFC4942] Davies, E., Krishnan, S., and P. Savola, "IPv6 Transition/
Co-existence Security Considerations", RFC 4942,
DOI 10.17487/RFC4942, September 2007,
<https://doi.org/10.17487/RFC4942>.
[RFC5095] Abley, J., Savola, P., and G. Neville-Neil, "Deprecation
of Type 0 Routing Headers in IPv6", RFC 5095,
DOI 10.17487/RFC5095, December 2007,
<https://doi.org/10.17487/RFC5095>.
[RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July
2011, <https://doi.org/10.17487/RFC6275>.
[RFC6554] Hui, J., Vasseur, JP., Culler, D., and V. Manral, "An IPv6
Routing Header for Source Routes with the Routing Protocol
for Low-Power and Lossy Networks (RPL)", RFC 6554,
DOI 10.17487/RFC6554, March 2012,
<https://doi.org/10.17487/RFC6554>.
[RFC7404] Behringer, M. and E. Vyncke, "Using Only Link-Local
Addressing inside an IPv6 Network", RFC 7404,
DOI 10.17487/RFC7404, November 2014,
<https://doi.org/10.17487/RFC7404>.
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[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://doi.org/10.17487/RFC7872>.
[RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J.,
Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
(SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020,
<https://doi.org/10.17487/RFC8754>.
[RFC8986] Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer,
D., Matsushima, S., and Z. Li, "Segment Routing over IPv6
(SRv6) Network Programming", RFC 8986,
DOI 10.17487/RFC8986, February 2021,
<https://doi.org/10.17487/RFC8986>.
[RFC9098] Gont, F., Hilliard, N., Doering, G., Kumari, W., Huston,
G., and W. Liu, "Operational Implications of IPv6 Packets
with Extension Headers", RFC 9098, DOI 10.17487/RFC9098,
September 2021, <https://doi.org/10.17487/RFC9098>.
[TIER1] "Tier 1 network", n.d.,
<https://en.wikipedia.org/wiki/Tier_1_network>.
Acknowledgments
The authors want to thank AfriNIC, Angani, China Telecom, Jared
Mauch, Sander Steffann, XiPeng Xiao, and Jan Zorz for allowing the
free use of their labs. Other thanks to Ben Campbell and Fernando
Gont who indicated a nice IPv6 hosting provider in Africa and South
America.
Special thanks as well to Professor Benoit Donnet for his support and
advices. This document would not have existed without his support.
Authors' Addresses
Éric Vyncke
Cisco
De Kleetlaan 64
1831 Diegem
Belgium
Email: evyncke@cisco.com
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Raphaël Léas
Université de Liège
Liege
Belgium
Email: raphael.leas@student.uliege.be
Justin Iurman
Université de Liège
Institut Montefiore B28
Allee de la Decouverte 10
4000 Liege
Belgium
Email: justin.iurman@uliege.be
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