[Docs] [txt|pdf] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: (draft-arifumi-v6ops-addr-select-ps) 00 01 02 03 04 05 06 07 08 09 RFC 5220

IPv6 Operations Working Group                               A. Matsumoto
Internet-Draft                                               T. Fujisaki
Intended status: Informational                                       NTT
Expires: December 19, 2008                                     R. Hiromi
                                                           Intec Netcore
                                                             K. Kanayama
                                                           INTEC Systems
                                                           June 17, 2008


     Problem Statement of Default Address Selection in Multi-prefix
        Environment: Operational Issues of RFC3484 Default Rules
                 draft-ietf-v6ops-addr-select-ps-09.txt

Status of this Memo

   By submitting this Internet-Draft, each author represents that any
   applicable patent or other IPR claims of which he or she is aware
   have been or will be disclosed, and any of which he or she becomes
   aware will be disclosed, in accordance with Section 6 of BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   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."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on December 19, 2008.

Abstract

   A single physical link can have multiple prefixes assigned to it.  In
   that environment, end hosts might have multiple IP addresses and be
   required to use them selectively.  RFC 3484 defines default source
   and destination address selection rules and is implemented in a
   variety of OS's.  But, it has been too difficult to use operationally
   for several reasons.  In some environment where multiple prefixes are
   assigned on a single physical link, the host using the default



Matsumoto, et al.       Expires December 19, 2008               [Page 1]

Internet-Draft            Address Selection PS                 June 2008


   address selection rules will experience some trouble in
   communication.  This document describes the possible problems that
   end hosts could encounter in an environment with multiple prefixes.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Scope of this document . . . . . . . . . . . . . . . . . .  3
   2.  Problem Statement  . . . . . . . . . . . . . . . . . . . . . .  4
     2.1.  Source Address Selection . . . . . . . . . . . . . . . . .  4
       2.1.1.  Multiple Routers on Single Interface . . . . . . . . .  4
       2.1.2.  Ingress Filtering Problem  . . . . . . . . . . . . . .  5
       2.1.3.  Half-Closed Network Problem  . . . . . . . . . . . . .  6
       2.1.4.  Combined Use of Global and ULA . . . . . . . . . . . .  7
       2.1.5.  Site Renumbering . . . . . . . . . . . . . . . . . . .  8
       2.1.6.  Multicast Source Address Selection . . . . . . . . . .  9
       2.1.7.  Temporary Address Selection  . . . . . . . . . . . . .  9
     2.2.  Destination Address Selection  . . . . . . . . . . . . . . 10
       2.2.1.  IPv4 or IPv6 prioritization  . . . . . . . . . . . . . 10
       2.2.2.  ULA and IPv4 dual-stack environment  . . . . . . . . . 11
       2.2.3.  ULA or Global Prioritization . . . . . . . . . . . . . 12
   3.  Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . 13
   4.  Security Considerations  . . . . . . . . . . . . . . . . . . . 14
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 14
   6.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
     6.1.  Normative References . . . . . . . . . . . . . . . . . . . 14
     6.2.  Informative References . . . . . . . . . . . . . . . . . . 15
   Appendix A.  Appendix. Revision History  . . . . . . . . . . . . . 15
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
   Intellectual Property and Copyright Statements . . . . . . . . . . 17




















Matsumoto, et al.       Expires December 19, 2008               [Page 2]

Internet-Draft            Address Selection PS                 June 2008


1.  Introduction

   In IPv6, a single physical link can have multiple prefixes assigned
   to it.  In such cases, an end-host may have multiple IP addresses
   assigned to an interface on that link.  In the IPv4-IPv6 dual stack
   environment or in a site connected to both a ULA [RFC4193] and
   Globally routable networks, an end-host typically has multiple IP
   addresses.  These are examples of the networks that we focus on in
   this document.  In such an environment, an end-host may encounter
   some communication troubles.

   Inappropriate source address selection at the end-host causes
   unexpected asymmetric routing, filtering by a router or discarding of
   packets because there is no route to the host.

   Considering a multi-prefix environment, destination address selection
   is also important for correct or better communication establishment.

   RFC 3484 [RFC3484] defines default source and destination address
   selection algorithms and is implemented in a variety of OS's.  But,
   it has been too difficult to use operationally for several reasons,
   such as lack of autoconfiguration method.  There are some problematic
   cases where the hosts using the default address selection rules
   encounter communication troubles.

   This document describes such possibilities of incorrect address
   selection which leads to dropping packets and communication failure.

1.1.  Scope of this document

   As other mechanisms already exist, the multi-homing techniques for
   achieving redundancy are basically out of our scope.

   We focus on an end-site network environment and unmanaged hosts in
   such an environment.  This is because address selection behavior at
   this kind of hosts is difficult to manipulate owing to the users'
   lack of knowledge, hosts' location, or massiveness of the hosts.

   The scope of this document is to sort out problematic cases related
   to address selection.  It includes problems that can be solved in the
   framework of RFC 3484 and problems that cannot.  For the latter, RFC
   3484 might be modified to meet their needs, or another address
   selection solution might be necessary.  For the former, an additional
   mechanism that mitigates the operational difficulty might be
   necessary.

   This document also includes simple solution analysis for each
   problematic case.  This analysis basically just focuses on whether



Matsumoto, et al.       Expires December 19, 2008               [Page 3]

Internet-Draft            Address Selection PS                 June 2008


   the case can be solved in the framework of RFC 3484 or not.  If not,
   some possible solutions are described.  Even if a case can be solved
   in the framework of RFC 3484, as mentioned above, it does not
   necessarily mean that there is no operational difficulty.  For
   example, in the environment stated above, it is not a feasible
   solution to configure each host's policy table by hand.  So, for such
   an solution, configuration pain is yet another common problem.


2.  Problem Statement

2.1.  Source Address Selection

2.1.1.  Multiple Routers on Single Interface

                          ==================
                          |    Internet    |
                          ==================
                             |          |
          2001:db8:1000::/36 |          | 2001:db8:8000::/36
                        +----+-+      +-+----+
                        | ISP1 |      | ISP2 |
                        +----+-+      +-+----+
                             |          |
         2001:db8:1000:::/48 |          | 2001:db8:8000::/48
                       +-----+---+ +----+----+
                       | Router1 | | Router2 |
                       +-------+-+ +-+-------+
                               |     |
          2001:db8:1000:1::/64 |     | 2001:db8:8000:1::/64
                               |     |
                        -----+-+-----+------
                             |
                           +-+----+ 2001:db8:1000:1::100
                           | Host | 2001:db8:8000:1::100
                           +------+

                                [Fig. 1]

   Generally speaking, there is no interaction between next-hop
   determination and address selection.  In this example, when a host
   starts a new connection and sends a packet via Router1, the host does
   not necessarily choose address 2001:db8:1000:1::100 given by Router1
   as the source address.  This causes the same problem as described in
   the next section 'Ingress Filtering Problem'.

   Solution analysis:




Matsumoto, et al.       Expires December 19, 2008               [Page 4]

Internet-Draft            Address Selection PS                 June 2008


      As this case depends on next hop selection, controling the address
      selection behavior at Host alone doesn't solve the entire problem.
      One possible solution for this case is adopting source address
      based routing at Router1 and Router2.  Another solution may be
      using static routing at Router1, Router2 and Host, and using the
      corresponding static address selection policy at Host.

2.1.2.  Ingress Filtering Problem

                        ==================
                        |    Internet    |
                        ==================
                             |       |
          2001:db8:1000::/36 |       | 2001:db8:8000::/36
                        +----+-+   +-+----+
                        | ISP1 |   | ISP2 |
                        +----+-+   +-+----+
                             |       |
         2001:db8:1000:::/48 |       | 2001:db8:8000::/48
                            ++-------++
                            | Router  |
                            +----+----+
                                 |  2001:db8:1000:1::/64
                                 |  2001:db8:8000:1::/64
                       ------+---+----------
                             |
                           +-+----+ 2001:db8:1000:1::100
                           | Host | 2001:db8:8000:1::100
                           +------+

                                [Fig. 2]

   When a relatively small site, which we call a "customer network", is
   attached to two upstream ISPs, each ISP delegates a network address
   block, which is usually /48, and a host has multiple IPv6 addresses.

   When the source address of an outgoing packet is not the one that is
   delegated by an upstream ISP, there is a possibility that the packet
   will be dropped at the ISP by its Ingress Filter.  Ingress filtering
   is becoming more popular among ISPs to mitigate the damage of DoS
   attacks.

   In this example, when the Router chooses the default route to ISP2
   and the Host chooses 2001:db8:1000:1::100 as the source address for
   packets sent to a host (2001:db8:2000::1) somewhere on the Internet,
   the packets may be dropped at ISP2 because of Ingress Filtering.

   Solution analysis:



Matsumoto, et al.       Expires December 19, 2008               [Page 5]

Internet-Draft            Address Selection PS                 June 2008


      One possible solution for this case is adopting source address
      based routing at Router.  Another solution may be using static
      routing at Router, and using the corresponding static address
      selection policy at Host.

2.1.3.  Half-Closed Network Problem

   You can see a second typical source address selection problem in a
   multihome site with global-closed mixed connectivity like in the
   figure below.  In this case, Host-A is in a multihomed network and
   has two IPv6 addresses, one delegated from each of the upstream ISPs.
   Note that ISP2 is a closed network and does not have connectivity to
   the Internet.

                           +--------+
                           | Host-C | 2001:db8:a000::1
                           +-----+--+
                                 |
                        ==============  +--------+
                        |  Internet  |  | Host-B | 2001:db8:8000::1
                        ==============  +--------+
                             |           |
           2001:db8:1000:/36 |           | 2001:db8:8000::/36
                        +----+-+   +-+---++
                        | ISP1 |   | ISP2 | (Closed Network/VPN tunnel)
                        +----+-+   +-+----+
                             |       |
           2001:db8:1000:/48 |       | 2001:db8:8000::/48
                            ++-------++
                            | Router  |
                            +----+----+
                                 |  2001:db8:1000:1::/64
                                 |  2001:db8:8000:1::/64
                       ------+---+----------
                             |
                          +--+-----+ 2001:db8:1000:1::100
                          | Host-A | 2001:db8:8000:1::100
                          +--------+

                                [Fig. 3]

   You do not need two physical network connections here.  The
   connection from the Router to ISP2 can be a logical link over ISP1
   and the Internet.

   When Host-A starts the connection to Host-B in ISP2, the source
   address of a packet that has been sent will be the one delegated from
   ISP2, that is 2001:db8:8000:1::100, because of rule 8 (longest



Matsumoto, et al.       Expires December 19, 2008               [Page 6]

Internet-Draft            Address Selection PS                 June 2008


   matching prefix) in RFC 3484.

   Host-C is located somewhere on the Internet and has IPv6 address
   2001:db8:a000::1.  When Host-A sends a packet to Host-C, the longest
   matching algorithm chooses 2001:db8:8000:1::100 for the source
   address.  In this case, the packet goes through ISP1 and may be
   filtered by ISP1's ingress filter.  Even if the packet is not
   filtered by ISP1, a return packet from Host-C cannot possibly be
   delivered to Host-A because the return packet is destined for 2001:
   db8:8000:1::100, which is closed from the Internet.

   The important point is that each host chooses a correct source
   address for a given destination address.  To solve this kind of
   network policy based address selection problems, it is likely that
   delivering additional information to a node fits better than
   algorithmic solutions that are local to the node.

   Solution analysis:
      This problem can be solved in the RFC 3484 framework.  For
      example, configuring some address selection policies into Host-A's
      RFC 3484 policy table can solve this problem.

2.1.4.  Combined Use of Global and ULA

                        ============
                        | Internet |
                        ============
                              |
                              |
                         +----+----+
                         |   ISP   |
                         +----+----+
                              |
              2001:db8:a::/48 |
                         +----+----+
                         | Router  |
                         +-+-----+-+
                           |     | 2001:db8:a:100::/64
          fd01:2:3:200:/64 |     | fd01:2:3:100:/64
                   -----+--+-   -+--+----
                        |           |
      fd01:2:3:200::101 |           |      2001:db8:a:100::100
                   +----+----+    +-+----+ fd01:2:3:100::100
                   | Printer |    | Host |
                   +---------+    +------+

                                [Fig. 4]




Matsumoto, et al.       Expires December 19, 2008               [Page 7]

Internet-Draft            Address Selection PS                 June 2008


   As RFC 4864 [RFC4864] describes, using a ULA may be beneficial in
   some scenarios.  If the ULA is used for internal communication,
   packets with ULA need to be filtered at the Router.

   This case does not presently create an address selection problem
   because of the dissimilarity between the ULA and the Global Unicast
   Address.  The longest matching rule of RFC 3484 chooses the correct
   address for both intra-site and extra-site communication.

   In the future, however, there is a possibility that the longest
   matching rule will not be able to choose the correct address anymore.
   That is the moment when the assignment of those Global Unicast
   Addresses starts, where the first bit is 1.  In RFC 4291 [RFC4291],
   almost all address spaces of IPv6, including those whose first bit is
   1, are assigned as Global Unicast Addresses.

   Namely, when we start to assign a part of the address block 8000::/1
   as the global unicast address and that part is used somewhere in the
   Internet, the longest matching rule ceases to function properly for
   the people trying to connect to the servers with those addresses.

   For example, when the destination host has an IPv6 address 8000::1,
   and the originating host has 2001:db8::1 and fd0:1::1, the source
   address will be fd00:1::1, because the longest matching bit length is
   0 for 2001:db8::1 and 1 for fd0:1::1 respectively.

   Solution analysis:
      This problem can be solved in the RFC 3484 framework.  For
      example, configuring some address selection policies into Host's
      RFC 3484 policy table can solve this problem.  Another solution is
      to modify RFC 3484 and define ULA's scope smaller than the global
      scope.

2.1.5.  Site Renumbering

   RFC 4192 [RFC4192] describes a recommended procedure for renumbering
   a network from one prefix to another.  An autoconfigured address has
   a lifetime, so by stopping advertisement of the old prefix, the
   autoconfigured address is eventually invalidated.

   However, invalidating the old prefix takes a long time.  You cannot
   stop routing to the old prefix as long as the old prefix is not
   removed from the host.  This can be a tough issue for ISP network
   administrators.

   There is a technique of advertising the prefix with the preferred
   lifetime zero, however, RFC 4862 [RFC4862] 5.5.4 does not absolutely
   prohibit the use of a deprecated address for a new outgoing



Matsumoto, et al.       Expires December 19, 2008               [Page 8]

Internet-Draft            Address Selection PS                 June 2008


   connection due to limitations relating to what applications are
   capable of doing."

                              +-----+---+
                              | Router  |
                              +----+----+
                                   |  2001:db8:b::/64  (new)
                                   |  2001:db8:a::/64 (old)
                         ------+---+----------
                               |
                            +--+---+ 2001:db8:b::100  (new)
                            | Host | 2001:db8:a::100 (old)
                            +------+

                                [Fig. 5]

   Solution analysis:
      This problem can be mitigated in the RFC 3484 framework.  For
      example, configuring some address selection policies into Host's
      RFC 3484 policy table can solve this problem.

2.1.6.  Multicast Source Address Selection

   This case is an example of site-local or global unicast
   prioritization.  When you send a multicast packet across site-
   borders, the source address of the multicast packet should be a
   globally routable address.  The longest matching algorithm, however,
   selects a ULA if the sending host has both a ULA and a Global Unicast
   Address.

   Solution analysis:
      This problem can be solved in the RFC 3484 framework.  For
      example, configuring some address selection policies into the
      sending host's RFC 3484 policy table can solve this problem.

2.1.7.  Temporary Address Selection

   RFC 3041 [RFC3041] defines a Temporary Address.  The usage of a
   Temporary Address has both pros and cons.  That is good for viewing
   web pages or communicating with the general public, but that is bad
   for a service that uses address-based authentication and for logging
   purposes.

   If you could turn the temporary address on and off, that would be
   better.  If you could switch its usage per service (destination
   address), that would also be better.  The same situation can be found
   when using HA (home address) and CoA (care-of address)in a Mobile
   IPv6 [RFC3775] network.



Matsumoto, et al.       Expires December 19, 2008               [Page 9]

Internet-Draft            Address Selection PS                 June 2008


   The Future Work section in RFC 3041 discusses that an API extension
   might be necessary to achieve a better address selection mechanism
   with finer granularity.

   Solution analysis:
      This problem can not be solved in the RFC 3484 framework.  A
      possible solution is to make applications to select desirable
      addresses by using the IPv6 Socket API for Source Address
      Selection defined in RFC 5014 [RFC5014].

2.2.  Destination Address Selection

2.2.1.  IPv4 or IPv6 prioritization

   The default policy table gives IPv6 addresses higher precedence than
   IPv4 addresses.  There seem to be many cases, however, where network
   administrators want to control the address selection policy of end-
   hosts the other way around.

                            +---------+
                            | Tunnel  |
                            | Service |
                            +--+---++-+
                               |   ||
                               |   ||
                        ===========||==
                        | Internet || |
                        ===========||==
                             |     ||
                192.0.2.0/24 |     ||
                        +----+-+   ||
                        | ISP  |   ||
                        +----+-+   ||
                             |     ||
               IPv4 (Native) |     || IPv6 (Tunnel)
                192.0.2.0/26 |     ||
                            ++-----++-+
                            | Router  |
                            +----+----+
                                 |  2001:db8:a:1::/64
                                 |  192.0.2.0/28
                                 |
                       ------+---+----------
                             |
                           +-+----+ 2001:db8:a:1::100
                           | Host | 192.0.2.2
                           +------+




Matsumoto, et al.       Expires December 19, 2008              [Page 10]

Internet-Draft            Address Selection PS                 June 2008


                                [Fig. 6]

   In the figure above, a site has native IPv4 and tunneled-IPv6
   connectivity.  Therefore, the administrator may want to set a higher
   priority for using IPv4 than using IPv6 because the quality of the
   tunnel network seems to be worse than that of the native transport.

   Solution analysis:
      This problem can be solved in the RFC 3484 framework.  For
      example, configuring some address selection policies into Host's
      RFC 3484 policy table can solve this problem.

2.2.2.  ULA and IPv4 dual-stack environment

   This is a special form of IPv4 and IPv6 prioritization.  When an
   enterprise has IPv4 Internet connectivity but does not yet have IPv6
   Internet connectivity, and the enterprise wants to provide site-local
   IPv6 connectivity, a ULA is the best choice for site-local IPv6
   connectivity.  Each employee host will have both an IPv4 global or
   private address and a ULA.  Here, when this host tries to connect to
   Host-B that has registered both A and AAAA records in the DNS, the
   host will choose AAAA as the destination address and the ULA for the
   source address.  This will clearly result in a connection failure.




























Matsumoto, et al.       Expires December 19, 2008              [Page 11]

Internet-Draft            Address Selection PS                 June 2008


                           +--------+
                           | Host-B | AAAA = 2001:db8::80
                           +-----+--+ A    = 192.0.2.1
                                 |
                        ============
                        | Internet |
                        ============
                             |  no IPv6 connectivity
                        +----+----+
                        | Router  |
                        +----+----+
                             |
                             | fd01:2:3::/48 (ULA)
                             | 192.0.2.128/25
                            ++--------+
                            | Router  |
                            +----+----+
                                 |  fd01:2:3:4::/64 (ULA)
                                 |  192.0.2.240/28
                       ------+---+----------
                             |
                           +-+------+ fd01:2:3:4::100 (ULA)
                           | Host-A | 192.0.2.245
                           +--------+

                                [Fig. 7]

   Solution analysis:
      This problem can be solved in the RFC 3484 framework.  For
      example, configuring some address selection policies into Host-A's
      RFC 3484 policy table can solve this problem.

2.2.3.  ULA or Global Prioritization

   Differentiating services by the client's source address is very
   common.  IP-address-based authentication is an typical example of
   this.  Another typical example is a web service that has pages for
   the public and internal pages for employees or involved parties.  Yet
   another example is DNS zone splitting.

   However, a ULA and IPv6 global address both have global scope, and
   RFC3484 default rules do not specify which address should be given
   priority.  This point makes IPv6 implementation of address-based
   service differentiation a bit harder.







Matsumoto, et al.       Expires December 19, 2008              [Page 12]

Internet-Draft            Address Selection PS                 June 2008


                            +--------+
                            | Host-B |
                            +-+--|---+
                              |  |
                      ===========|==
                      | Internet | |
                      ===========|==
                            |    |
                            |    |
                       +----+-+  +-->+------+
                       | ISP  +------+  DNS | 2001:db8:a::80
                       +----+-+  +-->+------+ fc12:3456:789a::80
                            |    |
            2001:db8:a::/48 |    |
        fc12:3456:789a::/48 |    |
                       +----+----|+
                       | Router  ||
                       +---+-----|+
                           |     |    2001:db8:a:100::/64
                           |     |    fc12:3456:789a:100::/64
                         --+-+---|-----
                             |   |
                           +-+---|--+ 2001:db8:a:100::100
                           | Host-A | fc12:3456:789a:100::100
                           +--------+

                                [Fig. 7]

   Solution analysis:
      This problem can be solved in the RFC 3484 framework.  For
      example, configuring some address selection policies into Host-A's
      RFC 3484 policy table can solve this problem.


3.  Conclusion

   We have covered problems related to destination or source address
   selection.  These problems have their roots in the situation where
   end-hosts have multiple IP addresses.  In this situation, every end-
   host must choose an appropriate destination and source address, which
   cannot be achieved only by routers.

   It should be noted that end-hosts must be informed about routing
   policies of their upstream networks for appropriate address
   selection.  A site administrator must consider every possible address
   false-selection problem and take countermeasures beforehand.





Matsumoto, et al.       Expires December 19, 2008              [Page 13]

Internet-Draft            Address Selection PS                 June 2008


4.  Security Considerations

   When an intermediate router performs policy routing (e.g. source
   address based routing), inappropriate address selection causes
   unexpected routing.  For example, in the network described in 2.1.3,
   when Host-A uses a default address selection policy and chooses an
   inappropriate address, a packet sent to VPN can be delivered to a
   location via the Internet.  This issue can lead to packet
   eavesdropping or session hijack.  However, sending the packet back to
   the correct path from the attacker to the node is not easy, so these
   two risks are not serious.

   As documented in the security consideration section in RFC 3484,
   address selection algorithms expose a potential privacy concern.
   When a malicious host can make a target host perform address
   selection, for example by sending a anycast or a multicast packet,
   the malicious host can get knowledge multiple addresses attached to
   the target host.  In a case like 2.1.4, if an attacker can make Host
   to send a multicast packet and Host performs the default address
   selection algorithm, the attacker may be able to determine the ULAs
   attached to the Host.

   These security risks have roots in inappropriate address selection.
   Therefore, if a countermeasure is taken, and hosts always select an
   appropriate address that is suitable to a site's network structure
   and routing, these risks can be avoided.


5.  IANA Considerations

   This document has no actions for IANA.


6.  References

6.1.  Normative References

   [RFC3041]  Narten, T. and R. Draves, "Privacy Extensions for
              Stateless Address Autoconfiguration in IPv6", RFC 3041,
              January 2001.

   [RFC3484]  Draves, R., "Default Address Selection for Internet
              Protocol version 6 (IPv6)", RFC 3484, February 2003.

   [RFC3775]  Johnson, D., Perkins, C., and J. Arkko, "Mobility Support
              in IPv6", RFC 3775, June 2004.

   [RFC4192]  Baker, F., Lear, E., and R. Droms, "Procedures for



Matsumoto, et al.       Expires December 19, 2008              [Page 14]

Internet-Draft            Address Selection PS                 June 2008


              Renumbering an IPv6 Network without a Flag Day", RFC 4192,
              September 2005.

   [RFC4193]  Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast
              Addresses", RFC 4193, October 2005.

   [RFC4291]  Hinden, R. and S. Deering, "IP Version 6 Addressing
              Architecture", RFC 4291, February 2006.

   [RFC4862]  Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
              Address Autoconfiguration", RFC 4862, September 2007.

   [RFC4864]  Van de Velde, G., Hain, T., Droms, R., Carpenter, B., and
              E. Klein, "Local Network Protection for IPv6", RFC 4864,
              May 2007.

   [RFC5014]  Nordmark, E., Chakrabarti, S., and J. Laganier, "IPv6
              Socket API for Source Address Selection", RFC 5014,
              September 2007.

6.2.  Informative References


Appendix A.  Appendix. Revision History

   01:
      IP address notations changed to documentation address.
      Description of solutions deleted.
   02:
      Security considerations section rewritten according to comments
      from SECDIR.
   03:
      Intended status changed to Informational.
   04:
      This version reflects comments from IESG members.
   05:
      This version reflects comments from IESG members and Bob Hinden.
   06:
      This version reflects comments from Thomas Narten.
   07:
      This version reflects comments from Alfred Hoenes.
   08:
      Solution analysis for the section 2.1.6 was added.
   09:







Matsumoto, et al.       Expires December 19, 2008              [Page 15]

Internet-Draft            Address Selection PS                 June 2008


      Typos were fixed, thanks to Jari Arrko.


Authors' Addresses

   Arifumi Matsumoto
   NTT PF Lab
   Midori-Cho 3-9-11
   Musashino-shi, Tokyo  180-8585
   Japan

   Phone: +81 422 59 3334
   Email: arifumi@nttv6.net


   Tomohiro Fujisaki
   NTT PF Lab
   Midori-Cho 3-9-11
   Musashino-shi, Tokyo  180-8585
   Japan

   Phone: +81 422 59 7351
   Email: fujisaki@nttv6.net


   Ruri Hiromi
   Intec Netcore, Inc.
   Shinsuna 1-3-3
   Koto-ku, Tokyo  136-0075
   Japan

   Phone: +81 3 5665 5069
   Email: hiromi@inetcore.com


   Ken-ichi Kanayama
   INTEC Systems Institute, Inc.
   Shimoshin-machi 5-33
   Toyama-shi, Toyama  930-0804
   Japan

   Phone: +81 76 444 8088
   Email: kanayama_kenichi@intec-si.co.jp








Matsumoto, et al.       Expires December 19, 2008              [Page 16]

Internet-Draft            Address Selection PS                 June 2008


Full Copyright Statement

   Copyright (C) The IETF Trust (2008).

   This document is subject to the rights, licenses and restrictions
   contained in BCP 78, and except as set forth therein, the authors
   retain all their rights.

   This document and the information contained herein are provided on an
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
   THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
   OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
   THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.


Intellectual Property

   The IETF takes no position regarding the validity or scope of any
   Intellectual Property Rights or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; nor does it represent that it has
   made any independent effort to identify any such rights.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 78 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use of
   such proprietary rights by implementers or users of this
   specification can be obtained from the IETF on-line IPR repository at
   http://www.ietf.org/ipr.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at
   ietf-ipr@ietf.org.











Matsumoto, et al.       Expires December 19, 2008              [Page 17]


Html markup produced by rfcmarkup 1.108, available from http://tools.ietf.org/tools/rfcmarkup/