SIDR Operations Z. Yan
Internet-Draft CNNIC
Intended status: Informational R. Bush
Expires: 10 February 2023 Internet Initiative Japan
G.G. Geng
Jinan University
T. de Kock
RIPE NCC
August 2022
Avoidance for ROA Containing Multiple IP Prefixes
draft-ietf-sidrops-roa-considerations-03
Abstract
In RPKI, the address space holder needs to issue an ROA object when
authorizing one or more ASes to originate routes to IP prefix(es).
During ROA issurance process, the address space holder may need to
specify an origin AS for a list of IP prefixes. Additionally, the
address space holder is free to choose to put multiple prefixes into
a single ROA or issue separate ROAs for each prefix according to the
current specification. This memo analyzes some operational problems
which may arise from ROAs containing multiple IP prefixes and
recommends avoiding placing multiple IP prefixes in one ROA.
Status of This Memo
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Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Provisions Relating to IETF Documents (https://trustee.ietf.org/
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3
4. Suggestions . . . . . . . . . . . . . . . . . . . . . . . . . 3
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
8.1. Normative References . . . . . . . . . . . . . . . . . . 4
8.2. Informative References . . . . . . . . . . . . . . . . . 4
Appendix A. ROA Analysis . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
In Resource Public Key Infrastructure (RPKI), Route Origin
Authorization (ROA) is a digitally signed object which identifies
that a single AS has been authorized by the address space holder to
originate routes to one or more prefixes within the address
space[RFC6482].
Each ROA contains an "asID" field and an "ipAddrBlocks" field. The
"asID" field contains one single AS number which is authorized to
originate routes to the given IP address prefixes. The
"ipAddrBlocks" field contains one or more IP address prefixes to
which the AS is authorized to originate the routes. If the address
space holder needs to authorize more than one ASes to advertise the
same set of IP prefixes, the holder must issue multiple ROAs, one for
each AS number. However, at present there are no mandatory
requirements describing that the address space holders must issue a
separate ROA for each IP prefix or a ROA containing multiple IP
Sprefixes.
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2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Problem Statement
For a Certification Authority (CA) issuing ROAs containing multiple
IP prefixes, adding or deleting one <AS, IP_Prefix> pair causes the
(single) ROA for an AS to be withdrawn and reissued. All IP prefixes
for an AS share the same validation state and then this may affect
the stability and security of RPKI.
By default, ROAs have an extended validity period. Resource changes
can happen at any time during this validity period. A certificate
change can affect all ROAs using IP prefixes from the issuing
certificate. CAs should carefully coordinate ROA updates with
resource certificate updates. A CA can automate this process if a
single entity manages both the parent CA and the CA issuing the ROAs
(scenario D [[RFC8211] section 3]). However, in other deployment
scenarios, this coordination becomes more complex. Furthermore, for
the ROA containing multiple IP prefixes, the IP prefixes share the
same expiry configuration. If the ROA is not reissued timely, the
whole set of IP prefixes will be affected after expiry.
Using multiple ROA objects with single IP prefix also allows a CA
to affect routing over time based on certificate expiry. For
example, a prefix could be allowed to be originated from an AS only
for a specific period of time, such as some IP prefix was leased out
temporarily.
4. Suggestions
The following suggestions should be considered during the process of
ROA issurance:
1) It's the most important to guarantee the stability and security of
RPKI, and it is recommended to include a single IP prefix in each ROA
in default.
2) In some special scenarios, where the resource is very stable or a
CA has operational problems producing increased number of individual
ROAs, multiple IP prefixes may be aggregated in one ROA.
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5. Security Considerations
This memo does not give rise to additional security risks.
6. IANA Considerations
This document does not request any IANA action.
7. Acknowledgements
The authors would like to thanks the valuable comments made by
members of sidrops WG and the list will be updated later.
This work was supported by the Beijing Nova Program of Science and
Technology under grant Z191100001119113.
This document was produced using the xml2rfc tool [RFC2629].
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC6482] Lepinski, M., Kent, S., and D. Kong, "A Profile for Route
Origin Authorizations (ROAs)", RFC 6482,
DOI 10.17487/RFC6482, February 2012,
<https://www.rfc-editor.org/info/rfc6482>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8211] Kent, S. and D. Ma, "Adverse Actions by a Certification
Authority (CA) or Repository Manager in the Resource
Public Key Infrastructure (RPKI)", RFC 8211,
DOI 10.17487/RFC8211, September 2017,
<https://www.rfc-editor.org/info/rfc8211>.
8.2. Informative References
[RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
DOI 10.17487/RFC2629, June 1999,
<https://www.rfc-editor.org/info/rfc2629>.
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Appendix A. ROA Analysis
In order to illustrate the situations of the current ROA database,
the following analysis is made.
+-------------- -+----------------------+-------------------------+
| The total | The number of ROAs | The number of ROAs with |
| number of ROAs | with a single prefix | multiple prefixes |
+----------------+----------------------+-------------------------+
| 117898 | 92742 | 25156 |
+----------------+----------------------+-------------------------+
Figure 1: Statistical results of global ROAs
As shown in Figure. 1, by July 20th 2022, the total number of ROA
objects issued is about 117898. Based on the further analysis on
these ROA objects, it is found that the number of ROAs containing
only one prefix is about 92742 (78.66% of all ROA objects), and the
number of ROAs containing two or more prefixes is about 25156 (21.34%
of all ROA objects).
In the 25156 ROA objects which each one contains two or more
prefixes, the number of IP address prefixes are calculated and
analyzed. The statistical results are shown in Figure. 2.
+----------------+----------------+--------------------------------+
| The number of | The number of | The median number of prefixes |
| prefixes | ROAs | in ROA |
+----------------+----------------+--------------------------------+
| 271822 | 25156 | 3 |
+----------------+----------------+--------------------------------+
Figure 2: Statistical results of the ROAs with multiple prefixes
As described in Figure. 2, there are 271822 IP address prefixes in
the 25156 ROA objects. And the median number of prefixes in ROA is
3. In addition, four types of ROAs are analyzed and calculated
within the 25156 ROAs: ROAs each contains 2-10/11-50/51-100/>100 IP
address prefixes. The statistical results are presented in Figure.
3.
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+----------+----------+----------+----------+----------+-------+
| ROA | ROA with | ROA with | ROA with | ROA with | Total |
| types | 2-10 | 11-50 | 51-100 | >100 | number|
| | prefixes | prefixes | prefixes | prefixes | |
+----------+----------+----------+----------+----------+-------+
| The | 21461 | 3042 | 343 | 310 | 25156 |
| number | | | | | |
| of ROAs | | | | | |
+----------+----------+----------+----------+----------+-------+
| The | 85.31% | 12.09% | 1.36% | 1.23% | 100% |
| ratio of | | | | | |
| ROAs | | | | | |
+----------+----------+----------+----------+----------+-------+
| The | 78677 | 62156 | 23676 | 107313 |271822 |
| number | | | | | |
| of | | | | | |
| prefixes | | | | | |
+----------+----------+----------+----------+----------+-------+
| The | 28.94% | 22.87% | 8.71% | 39.48% | 100% |
| ratio of | | | | | |
| prefixes | | | | | |
+----------+----------+----------+----------+----------+-------+
Figure 3: Statistical results of four types of ROAs
As shown in Figure. 3, taking the first type of ROA as an example,
there are 21461 ROAs (85.31% of the 25156 ROA objects) containing
2-10 IP address prefixes, and the total number of IP prefixes in
these 21461 ROAs is 78677 (28.94% of the 271822 prefixes). It shows
that the address space holders tend to issue each ROA object with
multiple IP prefixes (more than 95% of ROAs containing 2-50
prefixes).
The longest and shortest validity periods of a single ROA is 28854
days and 2 days. In addition, the median validity period of ROA is
429 days.
Authors' Addresses
Zhiwei Yan
CNNIC
No.4 South 4th Street, Zhongguancun
Beijing, 100190
P.R. China
Email: yanzhiwei@cnnic.cn
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Randy Bush
Internet Initiative Japan
Email: randy@psg.com
Guanggang Geng
Jinan University
No.601, West Huangpu Avenue
Guangzhou
510632
China
Email: gggeng@jnu.edu.cn
Ties de Kock
RIPE NCC
Stationsplein 11
Amsterdam
Email: tdekock@ripe.net
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