[sidr] 4-byte vs 2 byte ASN (was re: I-D Action: draft-ietf-sidr-pfx-validate-03.txt)

"George, Wes" <wesley.george@twcable.com> Tue, 01 November 2011 21:30 UTC

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From: "George, Wes" <wesley.george@twcable.com>
To: "sidr@ietf.org" <sidr@ietf.org>
Date: Tue, 1 Nov 2011 14:05:51 -0400
Thread-Topic: 4-byte vs 2 byte ASN (was re: I-D Action: draft-ietf-sidr-pfx-validate-03.txt)
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Subject: [sidr] 4-byte vs 2 byte ASN (was re: I-D Action: draft-ietf-sidr-pfx-validate-03.txt)
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Posing the question about 4-byte ASNs in my review of the BGPSec design reqs draft yesterday makes me wonder about the same in pfx-validate. The draft makes reference to AS_PATH in several locations. I'm thinking that we need a comment early in the draft stating that for the remainder of the draft no distinction is being made between AS_PATH and AS4_PATH, and that this standard is expected to support origin validation of both. Or alternatively, specify that this validation is performed on AS4_PATH and require support for 4893 as a prerequisite for SIDR.
If we don't explicitly require hosts that support SIDR origin validation to support 4-byte ASN, we may also need some direction regarding specific handling for AS23456, such as to always treat as unknown since there is no way to determine validity for the combination of a prefix and a non-unique placeholder ASN (except for local TA), but we don't necessarily want those routes to be treated as invalid.

I'm not sure if some of this belongs within sidr-arch, roa-validation, origin-ops, etc, but a quick scan through those docs don't reveal any obvious references to 4893, AS4_PATH, etc.

Thanks
Wes George

> -----Original Message-----
> From: sidr-bounces@ietf.org [mailto:sidr-bounces@ietf.org] On Behalf Of
> internet-drafts@ietf.org
> Sent: Monday, October 31, 2011 2:21 PM
> To: i-d-announce@ietf.org
> Cc: sidr@ietf.org
> Subject: [sidr] I-D Action: draft-ietf-sidr-pfx-validate-03.txt
>
> A New Internet-Draft is available from the on-line Internet-Drafts
> directories. This draft is a work item of the Secure Inter-Domain
> Routing Working Group of the IETF.
>
>       Title           : BGP Prefix Origin Validation
>       Author(s)       : Pradosh Mohapatra
>                           John Scudder
>                           David Ward
>                           Randy Bush
>                           Rob Austein
>       Filename        : draft-ietf-sidr-pfx-validate-03.txt
>       Pages           : 13
>       Date            : 2011-10-31
>
>    To help reduce well-known threats against BGP including prefix mis-
>    announcing and monkey-in-the-middle attacks, one of the security
>    requirements is the ability to validate the origination AS of BGP
>    routes.  More specifically, one needs to validate that the AS number
>    claiming to originate an address prefix (as derived from the AS_PATH
>    attribute of the BGP route) is in fact authorized by the prefix
>    holder to do so.  This document describes a simple validation
>    mechanism to partially satisfy this requirement.
>
>
> A URL for this Internet-Draft is:
> http://www.ietf.org/internet-drafts/draft-ietf-sidr-pfx-validate-03.txt
>
> Internet-Drafts are also available by anonymous FTP at:
> ftp://ftp.ietf.org/internet-drafts/
>
> This Internet-Draft can be retrieved at:
> ftp://ftp.ietf.org/internet-drafts/draft-ietf-sidr-pfx-validate-03.txt
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