Secure Inter-Domain Routing T. Manderson Internet-Draft ICANN Intended status: Informational K. Sriram Expires: July 30, 2012 US NIST R. White Cisco January 27, 2012 Use Cases and Interpretation of RPKI Objects for Issuers and Relying Parties draft-ietf-sidr-usecases-04 Abstract This document provides use cases, directions, and interpretations for organizations and relying parties when creating or encountering RPKI object scenarios in the public RPKI. All of the above are discussed here in relation to the Internet routing system. 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- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on July 30, 2012. Copyright Notice Copyright (c) 2012 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 (http://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 extracted from this document must Manderson, et al. Expires July 30, 2012 [Page 1] Internet-Draft RPKI Use Case and Interpretations January 2012 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 1.2. Documentation Prefixes . . . . . . . . . . . . . . . . . . 4 1.3. Definitions . . . . . . . . . . . . . . . . . . . . . . . 4 1.4. Requirements Language . . . . . . . . . . . . . . . . . . 5 2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1. General interpretation of RPKI object semantics . . . . . 5 3. Origination Use Cases . . . . . . . . . . . . . . . . . . . . 6 3.1. Single Announcement . . . . . . . . . . . . . . . . . . . 6 3.2. Aggregate with a More Specific . . . . . . . . . . . . . . 7 3.3. Aggregate with a More Specific from a Different ASN . . . 7 3.4. Sub-allocation to a Multi-homed Customer . . . . . . . . . 8 3.5. Restriction of a New Allocation . . . . . . . . . . . . . 9 3.6. Restriction of New ASN . . . . . . . . . . . . . . . . . . 10 3.7. Restriction of a Part of an Allocation . . . . . . . . . . 10 3.8. Restriction of Prefix Length . . . . . . . . . . . . . . . 11 3.9. Restriction of Sub-allocation Prefix Length . . . . . . . 12 3.10. Aggregation and Origination by an Upstream . . . . . . . . 13 3.11. Rogue Aggregation and Origination by an Upstream . . . . . 15 4. Adjacency or Path Validation Use Cases . . . . . . . . . . . . 16 5. Partial Deployment Use Cases . . . . . . . . . . . . . . . . . 16 5.1. Parent Does Not Participate in RPKI . . . . . . . . . . . 16 5.2. Only Some Children Participate in RPKI . . . . . . . . . . 17 5.3. Grandchild Does Not Participate in RPKI . . . . . . . . . 18 6. Transfer Use Cases . . . . . . . . . . . . . . . . . . . . . . 19 6.1. Transfer of in-use prefix and autonomous system number . . 19 6.2. Transfer of in-use prefix . . . . . . . . . . . . . . . . 20 6.3. Transfer of unused prefix . . . . . . . . . . . . . . . . 21 7. Relying Party Use Cases . . . . . . . . . . . . . . . . . . . 21 7.1. Prefix-Origin Validation use cases . . . . . . . . . . . . 21 7.1.1. Covering ROA Prefix, maxLength Satisfied, and AS Match . . . . . . . . . . . . . . . . . . . . . . . . 22 7.1.2. Covering ROA Prefix, maxLength Exceeded, and AS Match . . . . . . . . . . . . . . . . . . . . . . . . 22 7.1.3. Covering ROA Prefix, maxLength Satisfied, and AS Mismatch . . . . . . . . . . . . . . . . . . . . . . . 22 7.1.4. Covering ROA Prefix, maxLength Exceeded, and AS Mismatch . . . . . . . . . . . . . . . . . . . . . . . 23 7.1.5. Covering ROA Prefix Not Found . . . . . . . . . . . . 23 7.1.6. Covering ROA Prefix and the ROA is an AS0 ROA . . . . 23 7.1.7. Covering ROA Prefix Not Found but ROAs Exist for a Manderson, et al. Expires July 30, 2012 [Page 2] Internet-Draft RPKI Use Case and Interpretations January 2012 Covering Set of More Specifics . . . . . . . . . . . . 24 7.1.8. AS_SET in Route and Covering ROA Prefix Not Found . . 24 7.1.9. Singleton AS in AS_SET (in the Route), Covering ROA Prefix, and AS Match . . . . . . . . . . . . . . . 24 7.1.10. Singleton AS in AS_SET (in the Route), Covering ROA Prefix, and AS Mismatch . . . . . . . . . . . . . 25 7.1.11. Multiple ASs in AS_SET (in the Route) and Covering ROA Prefix . . . . . . . . . . . . . . . . . . . . . . 25 7.1.12. Multiple ASs in AS_SET (in the Route) and ROAs Exist for a Covering Set of More Specifics . . . . . . 25 7.2. ROA Expiry or Receipt of a CRL Revoking a ROA . . . . . . 26 7.2.1. ROA of Parent Prefix is Revoked . . . . . . . . . . . 26 7.2.2. ROA of Prefix Revoked while Parent Prefix Has Covering ROA Prefix with Different ASN . . . . . . . . 27 7.2.3. ROA of Prefix Revoked while that of Parent Prefix Prevails . . . . . . . . . . . . . . . . . . . . . . . 27 7.2.4. ROA of Grandparent Prefix Revoked while that of Parent Prefix Prevails . . . . . . . . . . . . . . . . 27 7.2.5. Expiry of ROA of Parent Prefix . . . . . . . . . . . . 27 7.2.6. Expiry of ROA of Prefix while Parent Prefix Has Covering ROA with Different ASN . . . . . . . . . . . 28 7.2.7. Expiry of ROA of Prefix while that of Parent Prefix Prevails . . . . . . . . . . . . . . . . . . . 28 7.2.8. Expiry of ROA of Grandparent Prefix while that of Parent Prefix Prevails . . . . . . . . . . . . . . . . 28 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 28 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28 10. Security Considerations . . . . . . . . . . . . . . . . . . . 29 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 29 11.1. Normative References . . . . . . . . . . . . . . . . . . . 29 11.2. Informative References . . . . . . . . . . . . . . . . . . 29 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 30 Manderson, et al. Expires July 30, 2012 [Page 3] Internet-Draft RPKI Use Case and Interpretations January 2012 1. Introduction This document provides use cases, directions, and interpretations for organizations and relying parties when creating or encountering RPKI object scenarios in the public RPKI. All of the above are discussed here in relation to the Internet routing system. 1.1. Terminology It is assumed that the reader is familiar with the terms and concepts described in "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile" [RFC5280], "A Profile for X.509 PKIX Resource Certificates" [I-D.ietf-sidr-res-certs] "X.509 Extensions for IP Addresses and AS Identifiers" [RFC3779], "A Profile for Route Origin Authorizations (ROAs)" [I-D.ietf-sidr-roa-format], "Validation of Route Origination in BGP using the Resource Certificate PKI and ROAs" [I-D.ietf-sidr-roa-validation], and BGP Prefix Origin Validation" [I-D.ietf-sidr-pfx-validate]. 1.2. Documentation Prefixes The documentation prefixes recommended in [RFC5737] are insufficient for use as example prefixes in this document. Therefore, this document uses RFC1918 [RFC1918] address space for constructing example prefixes. 1.3. Definitions The following definitions are in use in this document. Some of these definitions are reused or adapted from [I-D.ietf-sidr-pfx-validate] with authors' permission. Resource: An IP address prefix (simply called prefix or subnet) or an Autonomous System Number (ASN). Allocation: A set of resources provided to an entity or organization for its use. Sub-allocation: A set of resources subordinate to an allocation assigned to another entity or organization. Prefix: A prefix consists of a pair (IP address, prefix length), interpreted as is customary (see [RFC4632]). Route: Data derived from a received BGP update, as defined in [RFC4271], Section 1.1. The Route includes one Prefix and an AS_PATH, among other things. Manderson, et al. Expires July 30, 2012 [Page 4] Internet-Draft RPKI Use Case and Interpretations January 2012 ROA prefix: The Prefix from a ROA. ROA ASN: The origin ASN from a ROA. Route prefix: A Prefix derived from a route. Route origin ASN: The origin AS number derived from a Route. The origin AS number is the rightmost AS in the final segment of the AS_PATH attribute in the Route if that segment is of type AS_SEQUENCE, or NONE if the final segment of the AS_PATH attribute is of any type other than AS_SEQUENCE. Covering ROA prefix: A ROA prefix that is an exact match or a less specific when compared to the route prefix in consideration. In other words, the route prefix is said to have a covering ROA prefix when there exists a ROA such that the ROA prefix length is less than or equal to the route prefix length and the ROA prefix address matches the route prefix address for all bits specified by the ROA prefix length. Covering ROA: If a ROA contains a covering ROA prefix for a route prefix in consideration, then the ROA is said to be a covering ROA for the route prefix. No covering ROA: No covering ROA exists for a route prefix in consideration. No other covering ROA: No other covering ROA exists (besides what is (are) already cited) for a route prefix in consideration. Multi-homed prefix or subnet: A prefix (i.e., subnet) that is originated from two or more Autonomous Systems to which the subnet is connected. 1.4. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119. 2. Overview 2.1. General interpretation of RPKI object semantics It is important that in the interpretation of relying parties (RP), or relying party routing software, that a 'make before break' stance is applied. This means that a RP should implement a routing decision Manderson, et al. Expires July 30, 2012 [Page 5] Internet-Draft RPKI Use Case and Interpretations January 2012 process where a route is assumed to be intended (i.e., considered unsuspicious) unless proven otherwise by the existence of a valid RPKI object. For all of the cases in this document it is assumed that RPKI objects validate in accordance with [I-D.ietf-sidr-res-certs] and [I-D.ietf-sidr-arch]. In other words, we assume that corrupted RPKI objects, if any, have been detected and eliminated. While many of the examples provided here illustrate organizations using their own autonomous system numbers to originate routes, it should be recognized that a prefix holder need not necessarily be the holder of the autonomous system number used for the route origination. 3. Origination Use Cases This section deals with the various use cases where an organization has Internet resources and will announce routes to the Internet. It is based on operational observations of the existing routing system. In the following use cases, the phrase "relying parties interpret the route as intended" is generally meant to indicate that "relying parties interpret an announced route as having a valid origination AS." 3.1. Single Announcement An organization (Org A with ASN 64496) has been allocated the prefix 10.1.2.0/24. It wishes to announce the /24 prefix from ASN 64496 such that relying parties interpret the route as intended. The desired announcement (and organization) would be: +----------------------------------------------+ | Prefix | Origin AS | Organization | +----------------------------------------------+ | 10.1.2.0/24 | AS64496 | Org A | +----------------------------------------------+ The issuing party should create a ROA containing the following: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64496 | 10.1.2.0/24 | 24 | +----------------------------------------------+ Manderson, et al. Expires July 30, 2012 [Page 6] Internet-Draft RPKI Use Case and Interpretations January 2012 3.2. Aggregate with a More Specific An organization (Org A with ASN 64496) has been allocated the prefix 10.1.0.0/16. It wishes to announce the more specific prefix 10.1.0.0/20 from ASN 64496 as well as the aggregate route such that relying parties interpret the routes as intended. The desired announcements (and organization) would be: +----------------------------------------------+ | Prefix | Origin AS | Organization | +----------------------------------------------+ | 10.1.0.0/16 | AS64496 | Org A | | 10.1.0.0/20 | AS64496 | Org A | +----------------------------------------------+ The issuing party should create a ROA containing the following: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64496 | 10.1.0.0/16 | 16 | | |-----------------------------------+ | | 10.1.0.0/20 | 20 | +----------------------------------------------+ 3.3. Aggregate with a More Specific from a Different ASN An organization (Org A with ASN 64496 and ASN 64499) has been allocated the prefix 10.1.0.0/16. It wishes to announce the more specific prefix 10.1.0.0/20 from ASN 64499 as well as the aggregate route from ASN 64496 such that relying parties interpret the routes as intended. The desired announcements (and organization) would be: +---------------------------------------------+ | Prefix | Origin AS |Organization | +---------------------------------------------+ | 10.1.0.0/16 | AS64496 | Org A | | 10.1.0.0/20 | AS64499 | Org A | +---------------------------------------------+ The issuing party should create ROAs containing the following: Manderson, et al. Expires July 30, 2012 [Page 7] Internet-Draft RPKI Use Case and Interpretations January 2012 +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64496 | 10.1.0.0/16 | 16 | +----------------------------------------------+ +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64499 | 10.1.0.0/20 | 20 | +----------------------------------------------+ 3.4. Sub-allocation to a Multi-homed Customer An organization (Org A with ASN 64496) has been allocated the prefix 10.1.0.0/16; it wishes to announce the more specific prefix 10.1.0.0/20 from ASN 64496. It has further delegated 10.1.16.0/20 to a customer (Org B with ASN 64511) who is multi-homed and will originate the prefix route from ASN 64511. ASN 64496 will also announce the aggregate route such that relying parties interpret the routes as intended. The desired announcements (and organization) would be: +---------------------------------------------+ | Prefix | Origin AS |Organization | +---------------------------------------------+ | 10.1.0.0/16 | AS64496 | Org A | | 10.1.0.0/20 | AS64496 | Org A | | 10.1.16.0/20 | AS64511 | Org B | +---------------------------------------------+ The issuing party should create ROAs containing the following: Manderson, et al. Expires July 30, 2012 [Page 8] Internet-Draft RPKI Use Case and Interpretations January 2012 Org A. +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64496 | 10.1.0.0/16 | 16 | | |-----------------------------------+ | | 10.1.0.0/20 | 20 | +----------------------------------------------+ Org B. +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64511 | 10.1.16.0/20 | 20 | +----------------------------------------------+ 3.5. Restriction of a New Allocation An organization has recently been allocated the prefix 10.1.0.0/16. Its network deployment is not yet ready to announce the prefix and wishes to restrict all possible announcements of 10.1.0.0/16 and more specifics in routing using RPKI. The following announcements would be considered undesirable: +---------------------------------------------+ | Prefix | Origin AS |Organization | +---------------------------------------------+ | 10.1.0.0/16 | ANY AS | ANY | | 10.1.0.0/20 | ANY AS | ANY | | 10.1.17.0/24 | ANY AS | ANY | +---------------------------------------------+ The issuing party should create a ROA containing the following: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 0 | 10.1.0.0/16 | 32 | +----------------------------------------------+ This is known as an AS0 ROA [I-D.ietf-sidr-roa-validation]. Manderson, et al. Expires July 30, 2012 [Page 9] Internet-Draft RPKI Use Case and Interpretations January 2012 3.6. Restriction of New ASN An organization has recently been allocated an additional ASN 64511. Its network deployment is not yet ready to use this ASN and wishes to restrict all possible uses of ASN 64511 using RPKI. The following announcements would be considered undesirable: +---------------------------------------------+ | Prefix | Origin AS |Organization | +---------------------------------------------+ | ANY | AS64511 | ANY | +---------------------------------------------+ It is currently not possible to restrict use of Autonomous System Numbers 3.7. Restriction of a Part of an Allocation An organization (Org A with ASN 64496) has been allocated the prefix 10.1.0.0/16. Its network topology permits the announcement of 10.1.0.0/17. Org A wishes to restrict any possible announcement of 10.1.128.0/17 or more specifics of that /17 using RPKI. The desired announcements would be: +---------------------------------------------+ | Prefix | Origin AS |Organization | +---------------------------------------------+ | 10.1.0.0/17 | AS64496 | Org A | +---------------------------------------------+ The following announcements would be considered undesirable: +---------------------------------------------+ | Prefix | Origin AS |Organization | +---------------------------------------------+ | 10.1.128.0/17 | ANY AS | ANY | | 10.1.128.0/24 | ANY AS | ANY | +---------------------------------------------+ The issuing party should create ROAs containing the following: Manderson, et al. Expires July 30, 2012 [Page 10] Internet-Draft RPKI Use Case and Interpretations January 2012 +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64496 | 10.1.0.0/17 | 17 | +----------------------------------------------+ +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 0 | 10.1.128.0/17 | 32 | +----------------------------------------------+ 3.8. Restriction of Prefix Length An organization (Org A with ASN 64496) has been allocated the prefix 10.1.0.0/16; it wishes to announce the aggregate and any or all more specific prefixes up to and including a maximum length of /20, but never any more specific than a /20. Examples of the desired announcements (and organization) would be: +---------------------------------------------+ | Prefix | Origin AS |Organization | +---------------------------------------------+ | 10.1.0.0/16 | AS64496 | Org A | | 10.1.0.0/17 | AS64496 | Org A | | ... | AS64496 | Org A | | 10.1.128.0/20 | AS64496 | Org A | +---------------------------------------------+ The following announcements would be considered undesirable: +---------------------------------------------+ | Prefix | Origin AS |Organization | +---------------------------------------------+ | 10.1.0.0/21 | ANY AS | ANY | | 10.1.0.0/22 | ANY AS | ANY | | ... | ANY AS | ANY | | 10.1.128.0/24 | ANY AS | ANY | +---------------------------------------------+ The issuing party should create a ROA containing the following: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ Manderson, et al. Expires July 30, 2012 [Page 11] Internet-Draft RPKI Use Case and Interpretations January 2012 | 64496 | 10.1.0.0/16 | 20 | +----------------------------------------------+ 3.9. Restriction of Sub-allocation Prefix Length An organization (Org A with ASN 64496) has been allocated the prefix 10.1.0.0/16; it sub-allocates several /20 prefixes to its multi-homed customers Org B with ASN 64501, and Org C with ASN 64499. It wishes to restrict those customers from advertising any corresponding routes more specific than a /22. The desired announcements would be: +---------------------------------------------+ | Prefix | Origin AS |Organization | +---------------------------------------------+ | 10.1.0.0/16 | AS64496 | Org A | | 10.1.0.0/20 | AS64501 | Org B | | 10.1.128.0/20 | AS64499 | Org C | | 10.1.4.0/22 | AS64501 | Org B +---------------------------------------------+ The following example announcements (and organization) would be considered undesirable: +---------------------------------------------+ | Prefix | Origin AS |Organization | +---------------------------------------------+ | 10.1.0.0/24 | AS64501 | Org B | | 10.1.128.0/24 | AS64499 | Org C | | ..... | ... | ... | | 10.1.0.0/23 | ANY AS | ANY | +---------------------------------------------+ The issuing party (Org A) should create ROAs containing the following: Manderson, et al. Expires July 30, 2012 [Page 12] Internet-Draft RPKI Use Case and Interpretations January 2012 For Org A: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64496 | 10.1.0.0/16 | 16 | +----------------------------------------------+ For Org B: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64501 | 10.1.0.0/20 | 22 | +----------------------------------------------+ For Org C: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64499 | 10.1.128.0/20 | 22 | +----------------------------------------------+ 3.10. Aggregation and Origination by an Upstream Consider four organizations with the following resources, which were acquired independently from any transit provider. +-------------------------------------------------+ | Organization | ASN | Prefix | +-------------------------------------------------+ | Org A | AS64496 | 10.1.0.0/24 | | Org B | AS64505 | 10.1.3.0/24 | | Org C | AS64499 | 10.1.1.0/24 | | Org D | AS64511 | 10.1.2.0/24 | +-------------------------------------------------+ These organizations share a common upstream provider Transit X (ASN 64497) that originates an aggregate of these prefixes with the permission of all four organizations. The desired announcements (and organization) would be: Manderson, et al. Expires July 30, 2012 [Page 13] Internet-Draft RPKI Use Case and Interpretations January 2012 +----------------------------------------------+ | Prefix | Origin AS | Organization | +----------------------------------------------+ | 10.1.0.0/24 | AS64496 | Org A | | 10.1.3.0/24 | AS64505 | Org B | | 10.1.1.0/24 | AS64499 | Org C | | 10.1.2.0/24 | AS64511 | Org D | | 10.1.0.0/22 | AS64497 | Transit X | +----------------------------------------------+ It is currently not possible for an upstream to make a valid aggregate announcement of independent prefixes. However the issuing parties should create ROAs containing the following: Org A: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64496 | 10.1.0.0/24 | 24 | +----------------------------------------------+ Org B: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64505 | 10.1.3.0/24 | 24 | +----------------------------------------------+ Org C: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64499 | 10.1.1.0/24 | 24 | +----------------------------------------------+ Org D: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64511 | 10.1.2.0/24 | 24 | +----------------------------------------------+ Manderson, et al. Expires July 30, 2012 [Page 14] Internet-Draft RPKI Use Case and Interpretations January 2012 3.11. Rogue Aggregation and Origination by an Upstream Consider four organizations with the following resources that were acquired independently from any transit provider. +-------------------------------------------------+ | Organization | ASN | Prefix | +-------------------------------------------------+ | Org A | AS64496 | 10.1.0.0/24 | | Org B | AS64503 | 10.1.3.0/24 | | Org C | AS64499 | 10.1.1.0/24 | | Org D | AS64511 | 10.1.2.0/24 | +-------------------------------------------------+ These organizations share a common upstream provider Transit X (ASN 64497) that originates an aggregate of these prefixes where possible. In this situation organization B (ASN 64503, 10.1.3.0/24) does not wish for its prefix to be aggregated by the upstream provider. The desired announcements (and organization) would be: +----------------------------------------------+ | Prefix | Origin AS | Organization | +----------------------------------------------+ | 10.1.0.0/24 | AS64496 | Org A | | 10.1.3.0/24 | AS64503 | Org B | | 10.1.1.0/24 | AS64499 | Org C | | 10.1.2.0/24 | AS64511 | Org D | | 10.1.0.0/23 | AS64497 | Transit X | +----------------------------------------------+ The following announcement would be undesirable: +----------------------------------------------+ | Prefix | Origin AS | Organization | +----------------------------------------------+ | 10.1.0.0/22 | AS64497 | Transit X | +----------------------------------------------+ It is currently not possible for an upstream to make a valid aggregate announcement of independent prefixes. However the issuing parties should create ROAs containing the following: Manderson, et al. Expires July 30, 2012 [Page 15] Internet-Draft RPKI Use Case and Interpretations January 2012 Org A: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64496 | 10.1.0.0/24 | 24 | +----------------------------------------------+ Org B: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64503 | 10.1.3.0/24 | 24 | +----------------------------------------------+ Org C: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64499 | 10.1.1.0/24 | 24 | +----------------------------------------------+ Org D: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64511 | 10.1.2.0/24 | 24 | +----------------------------------------------+ 4. Adjacency or Path Validation Use Cases The SIDR WG was recently re-chartered (April 2011) to address AS path validation. Use cases pertaining to adjacency or path validation are beyond the scope of this document and would be addressed in a separate document. 5. Partial Deployment Use Cases 5.1. Parent Does Not Participate in RPKI An organization (Org A with ASN 64511) is multi-homed and has been assigned the prefix 10.1.0.0/20 from its upstream (Transit X with ASN 64496). Org A wishes to announce the prefix 10.1.0.0/20 from ASN 64511 to its other upstream(s). Org A also wishes to create RPKI statements about the resource; however Transit X (ASN 64496) which Manderson, et al. Expires July 30, 2012 [Page 16] Internet-Draft RPKI Use Case and Interpretations January 2012 announces the aggregate 10.1.0.0/16 has not yet adopted RPKI. The desired announcements (and organization with RPKI adoption) would be: +----------------------------------------------------+ | Prefix | Origin AS |Organization | RPKI | +----------------------------------------------------+ | 10.1.0.0/20 | AS64511 | Org A | Yes | | 10.1.0.0/16 | AS64496 | Transit X | No | +----------------------------------------------------+ RPKI is strictly hierarchical; therefore if Transit X does not participate in RPKI, Org A is unable to validly issue RPKI objects. 5.2. Only Some Children Participate in RPKI An organization (Org A with ASN 64496) has been allocated the prefix 10.1.0.0/16 and participates in RPKI; it wishes to announce the more specific prefix 10.1.0.0/20 from ASN 64496. It has further delegated 10.1.16.0/20 and 10.1.32.0/20 to customers Org B with ASN 64511 and Org C with ASN 64502 (respectively) who are multi-homed. Org B (ASN 64511) does not participate in RPKI. Org C (ASN 64502) participates in RPKI. The desired announcements (and organization with RPKI adoption) would be: +----------------------------------------------------+ | Prefix | Origin AS |Organization | RPKI | +----------------------------------------------------+ | 10.1.0.0/16 | AS64496 | Org A | Yes | | 10.1.0.0/20 | AS64496 | Org A | Yes | | 10.1.16.0/20 | AS64511 | Org B | No | | 10.1.32.0/20 | AS64502 | Org C | YES | +----------------------------------------------------+ The issuing parties should create ROAs containing the following: Manderson, et al. Expires July 30, 2012 [Page 17] Internet-Draft RPKI Use Case and Interpretations January 2012 Org A: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64496 | 10.1.0.0/16 | 16 | +----------------------------------------------+ | | 10.1.0.0/20 | 20 | +----------------------------------------------+ Org A issues for Org B: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64511 | 10.1.16.0/20 | 20 | +----------------------------------------------+ Org C: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64502 | 10.1.32.0/20 | 20 | +----------------------------------------------+ 5.3. Grandchild Does Not Participate in RPKI Consider the previous example with an extension by where Org B, who does not participate in RPKI, further allocates 10.1.17.0/24 to Org X with ASN 64505. Org X does not participate in RPKI. The desired announcements (and organization with RPKI adoption) would be: +----------------------------------------------------+ | Prefix | Origin AS |Organization | RPKI | +----------------------------------------------------+ | 10.1.0.0/16 | AS64496 | Org A | Yes | | 10.1.0.0/20 | AS64496 | Org A | Yes | | 10.1.16.0/20 | AS64511 | Org B | No | | 10.1.32.0/20 | AS64502 | Org C | YES | | 10.1.17.0/24 | AS64505 | Org X | No | +----------------------------------------------------+ The issuing parties should create ROAs containing the following: Manderson, et al. Expires July 30, 2012 [Page 18] Internet-Draft RPKI Use Case and Interpretations January 2012 Org A: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64496 | 10.1.0.0/16 | 16 | +----------------------------------------------+ | | 10.1.0.0/20 | 20 | +----------------------------------------------+ Org A issues for Org B: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64511 | 10.1.16.0/20 | 20 | +----------------------------------------------+ Org A issues for Org B's customer Org X: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64505 | 10.1.17.0/24 | 24 | +----------------------------------------------+ Org C: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64502 | 10.1.32.0/20 | 20 | +----------------------------------------------+ 6. Transfer Use Cases For transfer use cases, based on the preceding sections, it should be easy to deduce what new ROAs need to be created and what existing ones need to be maintained (or revoked). The resource transfer and timing of revocation/creation of the ROAs need to be performed based on the make-before-break principle and using suitable RIR procedures. 6.1. Transfer of in-use prefix and autonomous system number Organization A holds the resource 10.1.0.0/20 and it is currently in use and originated from AS64496 with valid RPKI objects in place. Organization B has acquired both the prefix and ASN and desires an RPKI transfer on a particular date and time without adversely affecting the operational use of the resource. Manderson, et al. Expires July 30, 2012 [Page 19] Internet-Draft RPKI Use Case and Interpretations January 2012 The following RPKI objects would be created/revoked: For Org. A, revoke the following ROA: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64496 | 10.1.0.0/20 | 20 | +----------------------------------------------+ For Org. B, add the following ROA: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64496 | 10.1.0.0/20 | 20 | +----------------------------------------------+ 6.2. Transfer of in-use prefix Organization A holds the resource 10.1.0.0/16 and it is currently in use and originated from AS64496 with valid RPKI objects in place. Organization A has agreed to transfer the entire /16 address block to Organization B and will no longer originate the prefix or more specifics of it. Consequently, Organization B desires an RPKI transfer of this resource on a particular date and time. This prefix will be originated by AS64511 as a result of this transfer. The following RPKI objects would be created/revoked: For Org. A, revoke the following ROA: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64496 | 10.1.0.0/16 | 16 | +----------------------------------------------+ For Org. B, add the following ROA when the resource certificate for 10.1.0.0/16 is issued to them (Org. B): +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64511 | 10.1.0.0/16 | 16 | +----------------------------------------------+ Manderson, et al. Expires July 30, 2012 [Page 20] Internet-Draft RPKI Use Case and Interpretations January 2012 6.3. Transfer of unused prefix Organization A holds the resources 10.1.0.0/16 and AS64507 (with RPKI objects). Organization A currently announces 10.1.0.0/16 from AS64507. Organization B has acquired an unused portion (10.1.4.0/24) of the prefix from Organization A, and desires an RPKI transfer on a particular date and time. Organization B will originate a route 10.1.4.0/24 from AS64496 The following RPKI objects would be created/sustained: For Org. A, leave the following ROA unchanged: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64507 | 10.1.0.0/16 | 16 | +----------------------------------------------+ For Org. B, add the following ROA when the resource certificate for 10.1.4.0/24 is issued to them (Org. B): +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64496 | 10.1.4.0/24 | 24 | +----------------------------------------------+ Organization A may optionally provide ROA coverage for Organization B by creating the following ROA preceding the RPKI transfer. The ROA itself is then naturally revoked when 10.1.4.0/24 is transferred to Organization B's resource certificate. Org. A adds the following ROA: +----------------------------------------------+ | asID | address | maxLength | +----------------------------------------------+ | 64496 | 10.1.4.0/24 | 24 | +----------------------------------------------+ 7. Relying Party Use Cases 7.1. Prefix-Origin Validation use cases These use cases try to systematically enumerate the situations a relying party may encounter while receiving a BGP update and making use of ROA information to interpret the validity of the prefix-origin Manderson, et al. Expires July 30, 2012 [Page 21] Internet-Draft RPKI Use Case and Interpretations January 2012 information in the routes derived from the update. We enumerate the situations or scenarios and include a recommendation for the expected outcome of prefix-origin validation. For a description of prefix- origin validation algorithms, see [I-D.ietf-sidr-roa-validation] and [I-D.ietf-sidr-pfx-validate]. We use the terms Valid, Invalid, and 'Not Found' as defined in [I-D.ietf-sidr-pfx-validate]. Also see [RFC6472] for work-in-progress in the IDR WG to deprecate AS_SETs in BGP updates. The use cases described here can be potentially used as test cases for testing and evaluation of prefix-origin validation in router implementations; see for example [BRITE]. 7.1.1. Covering ROA Prefix, maxLength Satisfied, and AS Match ROA: {10.1.0.0/16, maxLength = 20, AS64496} Route has {10.1.0.0/17, Origin = AS64496} Recommended RPKI prefix-origin validation interpretation: Route is Valid. Comment: The route prefix has a covering ROA prefix, and the route origin ASN matches the ROA ASN. This is a straightforward prefix- origin validation use case; it follows from the primary intention of creation of ROA by a prefix owner. 7.1.2. Covering ROA Prefix, maxLength Exceeded, and AS Match ROA: {10.1.0.0/16, maxLength = 20, AS64496} Route has {10.1.0.0/22, Origin = AS64496} No other covering ROA Recommended RPKI prefix-origin validation interpretation: Route is Invalid. Comment: In this case the maxLength specified in the ROA is exceeded by the route prefix. 7.1.3. Covering ROA Prefix, maxLength Satisfied, and AS Mismatch ROA: {10.1.0.0/16, maxLength = 24, AS64496} Route has {10.1.88.0/24, Origin = AS64511} No other covering ROA Recommended RPKI prefix-origin validation interpretation: Route is Manderson, et al. Expires July 30, 2012 [Page 22] Internet-Draft RPKI Use Case and Interpretations January 2012 Invalid. Comment: In this case an AS other than the one specified in the ROA is originating the route. This may be a prefix or subprefix hijack situation. 7.1.4. Covering ROA Prefix, maxLength Exceeded, and AS Mismatch ROA: {10.1.0.0/16, maxLength = 22, AS64496} Route has {10.1.88.0/24, Origin = AS64511} No other covering ROA Recommended RPKI prefix-origin validation interpretation: Route is Invalid. Comment: In this case the maxLength specified in the ROA is exceeded by the route prefix, and also an AS other than the one specified in the ROA is originating the route. This may be a subprefix hijack situation. 7.1.5. Covering ROA Prefix Not Found Route has {10.1.3.0/24, Origin = AS64511} No covering ROA Recommended RPKI prefix-origin validation interpretation: Route's validation status is 'Not Found'. Comment: In this case there is no covering ROA for the route prefix. It could be a case of prefix or subprefix hijack situation, but this announcement does not contradict any existing ROA. During partial deployment, there would be some legitimate prefix-origin announcements for which ROAs may not have been issued yet. 7.1.6. Covering ROA Prefix and the ROA is an AS0 ROA ROA: {10.1.0.0/16, maxLength = 32, AS0} Route has {10.1.5.0/24, Origin = AS64511} Recommended RPKI prefix-origin validation interpretation: Route's validation status is Invalid. Comment: An AS0 ROA implies by definition that the prefix listed in it and all of the more specifics of that prefix should not be used in Manderson, et al. Expires July 30, 2012 [Page 23] Internet-Draft RPKI Use Case and Interpretations January 2012 a routing context [I-D.ietf-sidr-roa-validation]. 7.1.7. Covering ROA Prefix Not Found but ROAs Exist for a Covering Set of More Specifics ROA: {10.1.0.0/18, maxLength = 20, AS64496} ROA: {10.1.64.0/18, maxLength = 20, AS64496} ROA: {10.1.128.0/18, maxLength = 20, AS64496} ROA: {10.1.192.0/18, maxLength = 20, AS64496} Route has {10.1.0.0/16, Origin = AS64496} No covering ROA Recommended RPKI prefix-origin validation interpretation: Route's validation status is 'Not Found'. Comment: In this case the route prefix is an aggregate (/16), and it turns out that there exit ROAs for more specifics (/18s) that, if combined, can help support validation of the announced prefix-origin pair. But it is very hard in general to breakup an announced prefix into constituent more specifics and check for ROA coverage for those more specifics, and hence this type of accommodation is not recommended. 7.1.8. AS_SET in Route and Covering ROA Prefix Not Found Route has {10.1.0.0/16, AS_SET [AS64496, AS64497, AS64498, AS64499] appears in the right most position in the AS_PATH} No covering ROA Recommended RPKI prefix-origin validation interpretation: Route's validation status is 'Not Found'. Comment: An extremely small percentage (~0.1%) of eBGP updates are seen to have an AS_SET in them; this is known as proxy aggregation. In this case, the route with the AS_SET does not conflict with any ROA (i.e., the route prefix has no covering ROA prefix). Therefore, the route gets 'Not Found' validation status. 7.1.9. Singleton AS in AS_SET (in the Route), Covering ROA Prefix, and AS Match Route has {10.1.0.0/24, AS_SET [AS64496] appears in the right most Manderson, et al. Expires July 30, 2012 [Page 24] Internet-Draft RPKI Use Case and Interpretations January 2012 position in the AS_PATH} ROA: {10.1.0.0/22, maxLength = 24, AS64496} Recommended RPKI prefix-origin validation interpretation: Route is Invalid. Comment: In the spirit of [RFC6472], any route with an AS_SET in it should not be considered valid (by ROA-based validation). If the route contains an AS_SET and a covering ROA prefix exists for the route prefix, then the route should get an Invalid status. (Note: AS match or mismatch consideration does not apply.) 7.1.10. Singleton AS in AS_SET (in the Route), Covering ROA Prefix, and AS Mismatch Route has {10.1.0.0/24, AS_SET [AS64496] appears in the right most position in the AS_PATH} ROA: {10.1.0.0/22, maxLength = 24, AS64511} Recommended RPKI prefix-origin validation interpretation: Route is Invalid. Comment: If the route contains an AS_SET and a covering ROA prefix exists for the route prefix, then the route should get an Invalid status. (Note: AS match or mismatch consideration does not apply.) 7.1.11. Multiple ASs in AS_SET (in the Route) and Covering ROA Prefix Route has {10.1.0.0/22, AS_SET [AS64496, AS64497, AS64498, AS64499] appears in the right most position in the AS_PATH} ROA: {10.1.0.0/22, maxLength = 24, AS64509} No other covering ROA. Recommended RPKI prefix-origin validation interpretation: Route is Invalid. Comment: If the route contains an AS_SET and a covering ROA prefix exists for the route prefix, then the route should get an Invalid status. 7.1.12. Multiple ASs in AS_SET (in the Route) and ROAs Exist for a Covering Set of More Specifics ROA: {10.1.0.0/18, maxLength = 20, AS64496} Manderson, et al. Expires July 30, 2012 [Page 25] Internet-Draft RPKI Use Case and Interpretations January 2012 ROA: {10.1.64.0/18, maxLength = 20, AS64497} ROA: {10.1.128.0/18, maxLength = 20, AS64498} ROA: {10.1.192.0/18, maxLength = 20, AS64499} Route has {10.1.0.0/16, AS_SET [AS64496, AS64497, AS64498, AS64499] appears in the right most position in the AS_PATH} No covering ROA Recommended RPKI prefix-origin validation interpretation: Route's validation status is 'Not Found'. Comment: In this case the aggregate of the prefixes in the ROAs is a covering prefix (i.e., exact match or less specific) relative to the route prefix. The ASs in each of the contributing ROAs together form a set that matches the AS_SET in the route. But it is very hard in general to breakup an announced prefix into constituent more specifics and check for ROA coverage for those more specifics. In any case, it may be noted once again that in the spirit of [RFC6472], any route with an AS_SET in it should not be considered valid (by ROA-based validation). In fact, the route in consideration would have received an Invalid status if the route prefix had at least one covering ROA prefix. 7.2. ROA Expiry or Receipt of a CRL Revoking a ROA Here we enumerate use cases corresponding to router actions when RPKI objects expire or are revoked. In the cases which follow, the terms "expired ROA" or "revoked ROA" are shorthand, and describe the expiry or revocation of the End Entity (EE) or Resource Certificate that causes a relying party to consider the corresponding ROA to have expired or revoked, respectively. 7.2.1. ROA of Parent Prefix is Revoked A certificate revocation list (CRL) is received which reveals that the ROA {10.1.0.0/22, maxLength = 24, ASN64496} is revoked. Further, a route exists in the Internet routing system for 10.1.3.0/24 originated from ASN64496. In absence of said revoked ROA, no covering ROA prefix exists for the route prefix (i.e., 10.1.3.0/24). The Relying Party interpretation would be: Route's validation status is 'Not Found' Manderson, et al. Expires July 30, 2012 [Page 26] Internet-Draft RPKI Use Case and Interpretations January 2012 7.2.2. ROA of Prefix Revoked while Parent Prefix Has Covering ROA Prefix with Different ASN A CRL is received which reveals that the ROA {10.1.3.0/24, maxLength = 24, ASN64496} is revoked. Further, a route exists in the Internet routing system for 10.1.3.0/24 originated from ASN64496. Additionally, a valid ROA exists for a parent prefix 10.1.0.0/22 and said ROA is {10.1.0.0/22, maxLength = 24, ASN64511}. No other covering ROA exists for the 10.1.3.0/24 prefix. The Relying Party interpretation would be: Route is Invalid. 7.2.3. ROA of Prefix Revoked while that of Parent Prefix Prevails A CRL is received which reveals that the ROA {10.1.3.0/24; maxLength = 24, ASN64496} is revoked. Further, a route exists in the Internet routing system for 10.1.3.0/24 originated from ASN64496. Additionally, a valid ROA exists for a parent prefix 10.1.0.0/22 and said ROA is {10.1.0.0/22, maxLength = 24, ASN64496}. The Relying Party interpretation would be: Route is Valid. (Clarification: Perhaps the revocation of ROA for prefix 10.1.3.0/24 was initiated just to eliminate redundancy.) 7.2.4. ROA of Grandparent Prefix Revoked while that of Parent Prefix Prevails A CRL is received which reveals that the ROA {10.1.0.0/20; maxLength = 24, ASN64496} is revoked. Further, a route exists in the Internet routing system for 10.1.3.0/24 originated from ASN64496. Additionally, a valid ROA exists for a parent prefix 10.1.0.0/22 and said ROA is {10.1.0.0/22, maxLength = 24, ASN64496}. The Relying Party interpretation would be: Route is Valid. (Clarification: ROA for less specific grandparent prefix 10.1.0.0/20 was revoked or withdrawn.) 7.2.5. Expiry of ROA of Parent Prefix A scan of the ROA list reveals that the ROA {10.1.0.0/22, maxLength = 24, ASN64496} has expired. Further, a route exists in the Internet routing system for 10.1.3.0/24 originated from ASN64496. In absence of said expired ROA, no covering ROA prefix exists for the route prefix (i.e., 10.1.3.0/24). The Relying Party interpretation would be: Route's validation status Manderson, et al. Expires July 30, 2012 [Page 27] Internet-Draft RPKI Use Case and Interpretations January 2012 is 'Not Found' 7.2.6. Expiry of ROA of Prefix while Parent Prefix Has Covering ROA with Different ASN A scan of the ROA list reveals that the ROA {10.1.3.0/24, maxLength = 24, ASN64496} has expired. Further, a route exists in the Internet routing system for 10.1.3.0/24 originated from ASN64496. Additionally, a valid ROA exists for a parent prefix 10.1.0.0/22 and said ROA is {10.1.0.0/22, maxLength = 24, ASN64511}. No other covering ROA exists for the prefix (i.e., 10.1.3.0/24). The Relying Party interpretation would be: Route is Invalid. 7.2.7. Expiry of ROA of Prefix while that of Parent Prefix Prevails A scan of the ROA list reveals that the ROA {10.1.3.0/24; maxLength = 24, ASN64496} has expired. Further, a route exists in the Internet routing system for 10.1.3.0/24 originated from ASN64496. Additionally, a valid ROA exists for a parent prefix 10.1.0.0/22 and said ROA is {10.1.0.0/22, maxLength = 24, ASN64496}. The Relying Party interpretation would be: Route is Valid. 7.2.8. Expiry of ROA of Grandparent Prefix while that of Parent Prefix Prevails A scan of the ROA list reveals that the ROA {10.1.0.0/20; maxLength = 24, ASN64496} has expired. Further, a route exists in the Internet routing system for 10.1.3.0/24 originated from ASN64496. Additionally, a valid ROA exists for a parent prefix 10.1.0.0/22 and said ROA is {10.1.0.0/22, maxLength = 24, ASN64496}. The Relying Party interpretation would be: Route is Valid. 8. Acknowledgements The authors are indebted to both Sandy Murphy and Sam Weiler for their guidance. Further, the authors would like to thank Steve Kent, Warren Kumari, Randy Bush, Curtis Villamizar, and Danny McPherson for their technical insight and review. 9. IANA Considerations This memo includes no request to IANA. Manderson, et al. Expires July 30, 2012 [Page 28] Internet-Draft RPKI Use Case and Interpretations January 2012 10. Security Considerations This memo requires no security considerations 11. References 11.1. Normative References [I-D.ietf-sidr-arch] Lepinski, M. and S. Kent, "An Infrastructure to Support Secure Internet Routing", draft-ietf-sidr-arch-13 (work in progress), May 2011. [I-D.ietf-sidr-res-certs] Huston, G., Michaelson, G., and R. Loomans, "A Profile for X.509 PKIX Resource Certificates", draft-ietf-sidr-res-certs-22 (work in progress), May 2011. [I-D.ietf-sidr-roa-format] Lepinski, M., Kent, S., and D. Kong, "A Profile for Route Origin Authorizations (ROAs)", draft-ietf-sidr-roa-format-12 (work in progress), May 2011. [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, January 2006. 11.2. Informative References [BRITE] "BRITE: BGPSEC/RPKI Interoperability Test and Evaluation", Developed by the National Institute of Standards and Technology (NIST), Gaithersburg, Maryland, . [I-D.ietf-sidr-pfx-validate] Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R. Austein, "BGP Prefix Origin Validation", draft-ietf-sidr-pfx-validate-03 (work in progress), October 2011. [I-D.ietf-sidr-roa-validation] Huston, G. and G. Michaelson, "Validation of Route Origination using the Resource Certificate PKI and ROAs", draft-ietf-sidr-roa-validation-10 (work in progress), November 2010. [RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and Manderson, et al. Expires July 30, 2012 [Page 29] Internet-Draft RPKI Use Case and Interpretations January 2012 E. Lear, "Address Allocation for Private Internets", BCP 5, RFC 1918, February 1996. [RFC3779] Lynn, C., Kent, S., and K. Seo, "X.509 Extensions for IP Addresses and AS Identifiers", RFC 3779, June 2004. [RFC4055] Schaad, J., Kaliski, B., and R. Housley, "Additional Algorithms and Identifiers for RSA Cryptography for use in the Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 4055, June 2005. [RFC4632] Fuller, V. and T. Li, "Classless Inter-domain Routing (CIDR): The Internet Address Assignment and Aggregation Plan", BCP 122, RFC 4632, August 2006. [RFC4893] Vohra, Q. and E. Chen, "BGP Support for Four-octet AS Number Space", RFC 4893, May 2007. [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., Housley, R., and W. Polk, "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 5280, May 2008. [RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70, RFC 5652, September 2009. [RFC5737] Arkko, J., Cotton, M., and L. Vegoda, "IPv4 Address Blocks Reserved for Documentation", RFC 5737, January 2010. [RFC6472] Kumari, W. and K. Sriram, "Recommendation for Not Using AS_SET and AS_CONFED_SET in BGP", BCP 172, RFC 6472, December 2011. Authors' Addresses Terry Manderson ICANN Email: terry.manderson@icann.org Kotikalapudi Sriram US NIST Email: ksriram@nist.gov Manderson, et al. Expires July 30, 2012 [Page 30] Internet-Draft RPKI Use Case and Interpretations January 2012 Russ White Cisco Email: russ@cisco.com Manderson, et al. Expires July 30, 2012 [Page 31]