Subject: I-D Action: draft-bi-savi-problem-02.txt

From: [email-masked]
Date: Mon, 30 Jan 2012 21:03:15 -0800

A New Internet-Draft is available from the on-line Internet-Drafts directories.

	Title           : Problem Statement of SAVI Beyond the First Hop
	Author(s)       : Jun Bi
                          Bingyang Liu
	Filename        : draft-bi-savi-problem-02.txt
	Pages           : 9
	Date            : 2012-01-30

   IETF Source Address Validation Improvements (SAVI) working group is
   chartered for source address validation within the first hop from the
   end hosts, i.e. preventing a node from spoofing the IP source address
   of another node in the same IP link.  For source address validation
   beyond the first hop (SAVI-BF), Ingress Filtering [BCP38]/[BCP84] is
   the best current practice.  However Ingress Filtering may drop
   legitimate packets (false positive) or fail to recognize spoofing
   packets (false negative) in case of asymmetric routing, which is not
   rare under SAVI-BF scenario.

   This document states the possible scenarios in which Ingress
   Filtering may have problems (false positive or false negative).  We
   claim that the reason of the problems is that the routers are lack of
   sufficient routing information to predict the incoming direction of a
   packet, since source address validation beyond the first hop should
   act consistently with the behavior of the routing system.  We also
   discuss the availability of the needed routing information under
   different routing environments.

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ftp://ftp.ietf.org/internet-drafts/draft-bi-savi-problem-02.txt