[Search] [txt|pdfized|bibtex] [Tracker] [Email] [Nits]

Versions: 00 01 02 03                                                   
Network Working Group                                            E. Lear
Internet-Draft                                             Cisco Systems
Expires: June 10, 2004                                 December 11, 2003


              Things MULTI6 Developers should think about
               draft-lear-multi6-things-to-think-about-00

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   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 June 10, 2004.

Copyright Notice

   Copyright (C) The Internet Society (2003). All Rights Reserved.

Abstract

   This document specifies a set of questions that authors should be
   prepared to answer as part of a solution to multihoming with IPv6.
   The questions do not assume that multihoming is the only problem of
   interest, nor do they demand a more general solution either.












Lear                     Expires June 10, 2004                  [Page 1]


Internet-Draft        MULTI6 Solution Questionaire         December 2003


1. Introduction

   At the time of this writing there are some six separate solutions
   looking at the problem of multihoming within IPv6 and related
   problems, such as the locator/identifier split.

   In order to sort through how proposed solutions compare against one
   another, and potentially, how they can borrow mechanisms and design
   decisions from one another, this document contains a list of pointed
   questions.

   This document contains only some useful questions.  There are others
   that should be added.  If you know of one, please email the author,
   as he has assuredly missed many.

   Unless it is blatantly obvious, each question contains some reasoning
   as to why it is being asked.  It is envisioned that no solution will
   answer every question with completeness, but that there will be
   tradeoffs to be made.  The answers by the various designers of
   solutions will hopefully shed some light on which tradeoffs we as a
   community wish to make.

   It would seem silly for people who have written out detailed answers
   to these questions to have to repeat the exercise. Therefore, a
   simple reference to existing documents will suffice, so long as the
   answer is complete.  If it is not complete, then feel free to
   reference it and add what text is necessary to make the answer
   complete.

   This document presumes a familiarity with RFC 3582 [2], and does not
   attempt to repeat the requirements work gathered there.




















Lear                     Expires June 10, 2004                  [Page 2]


Internet-Draft        MULTI6 Solution Questionaire         December 2003


2. The Questions

2.1 Routing

2.1.1 How will your solution solve the multihoming problem?

   That's why we're here.  Remember, a reference is fine.

2.1.2 Uniqueness

2.1.2.1 Does your solution address mobility?

   If so, how are rendezvous handled?  Can your solution handle both
   locators changing at the same time?  Should it?  If not, how will
   your solution interact with MOBILEIP-V6 [3] (MIPv6)

2.2 Identifiers and locators

2.2.1 Does your solution provide for a split between identifiers and
      locators?

2.2.2 What is the lifetime of a binding from an identifier to a locator?

2.2.3 How is the binding updated?

   Will transport connections remain up?

2.3 On The Wire

2.3.1 At what layer is your solution applied, and how?

   Is it applied in every packet?  If so, what fields are used?

2.3.2 Why is the layer you chose the correct one?

   Each layer has its benefits and tradeoffs.  For instance, transport
   layer solutions would require that EVERY transport be modified, while
   IP layer solutions may entail expansion of the packet or a change to
   the pseudo-header (thus requiring changes to the transport layer).

2.3.3 Does your solution expand the size of an IP packet?

   Expanding the size of an IP packet may cause excessive fragmentation
   in some circumstances.

2.3.4 Do you change the way fragmenting is handled?

   If you use a shim approach, do you fragment above or below the shim?



Lear                     Expires June 10, 2004                  [Page 3]


Internet-Draft        MULTI6 Solution Questionaire         December 2003


   How are fragments identified, so that they can be reassembled?  If
   you use any additional names, do they need to be associated with
   fragments?  If not, why not?  If so, how will that happen?

2.3.5 Are there any changes to ICMP error semantics?

   Do you create new codes?  If so, why and what do they mean? Will a
   host that is not aware of your scheme see them?

2.4 Names, Hosts, Endpoints, or none of the above?

2.4.1 Please explain the relationship of your solution to DNS

   If your solution uses new names for identifiers, please explain what
   mappings are defined, and how they are performed?

   If there are any additional administrative requirements, such as new
   zones or RR types to manage, please explain them as well.

2.4.2 Please explain interactions with "2-faced" DNS

   2-faced DNS is used so that hosts behind a NAT get one address for
   internal hosts, while hosts outside the NAT get another. Similar
   mechanisms are used for application layer gateways, such as SOCKS
   [5].

2.4.3 Does your solution require centralized registration?

   For instance, if you are using the DNS, what will be the top level
   domain, and how will the name space distribute through it?

   Also, how will the centralized registration be managed?

2.4.4 Have you checked for DNS circular dependencies?

   If you are using the DNS in your solution, is it required for
   connectivity?  What happens if the DNS fails?  Can communication
   between the DNS resolver and the server make use of your solution?
   What about between the application and the resolver?

2.4.5 What if a DNS server itself is multihomed?

   If a link fails or a service is dropped, how will it impact DNS?
   Again are there any dependency loops?  Perhaps diagram out your
   dependencies to make sure.

2.4.6 What application/API changes are needed?




Lear                     Expires June 10, 2004                  [Page 4]


Internet-Draft        MULTI6 Solution Questionaire         December 2003


   Will old code just work with the new mechanism?

2.4.7 Is this solution backward compatable with "old" IP version 6?

   Can it be deployed incrementally?  Please describe how.

   Does your solution impose requirements on non-multihomed/non-mobile
   hosts?

2.4.8 Is your solution backward compatable with IPv4?

   How will your mechanism interact with 6to4 gateways and IPv4 hosts?

2.4.9 How will your solution interact with other middleboxes?

   What are the implications for firewalls?  What are the interactions
   with NAT?  What are the interactions with web caches? What
   complications are introduced with your solution?

2.4.10 Are there any implications for scoped addressing?

   Please see RFC 3513 [1].  How does your mechanism interact with
   multicast?

   How does your solution interact with link-local addressing

   How does your solution interact with Son-Of-Sitelocal (whatever that
   will be)?

2.4.11 Are there any layer 2 implications to your proposal?

   While Ipv6 has a simplified approach to layer 2, perhaps you
   unsimplifiied it.  If so, please provide details.

2.4.12 Referrals

   How will your solution handle referrals, such as those within FTP?

   It must be possible for existing applications to continue to work.
   Referrals exist within various other protocols, such as so-called
   "peer to peer" applications.

2.5 Legal Stuff

   Are you introducing a namespace that might involve mnemonics? Doing
   so might introduce trademark concerns.  If so, how do you plan to
   address such concerns?




Lear                     Expires June 10, 2004                  [Page 5]


Internet-Draft        MULTI6 Solution Questionaire         December 2003


   Are there any organizations required to manage a new name space? If
   so, please describe what they are and how the method will scale.

















































Lear                     Expires June 10, 2004                  [Page 6]


Internet-Draft        MULTI6 Solution Questionaire         December 2003


3. Security Considerations

   How secure should a multi6 solution be?  This is a reasonable
   question for each solution to answer.  The author opines that the
   worst case should be no worse than what we have today.  However, any
   additional risks should be clearly stated by the authors.
   Considerable time should be spent on threat analysis.  Please see [4]
   for more details.











































Lear                     Expires June 10, 2004                  [Page 7]


Internet-Draft        MULTI6 Solution Questionaire         December 2003


4. Acknowledgments

   The author wishes to acknoledge everyone in the multi6 group and
   elsewhere that is putting forward proposals.  It is easy to ask
   questions like the ones found in this draft.  It is quite a bit
   harder to develop running code to answer them.













































Lear                     Expires June 10, 2004                  [Page 8]


Internet-Draft        MULTI6 Solution Questionaire         December 2003


Normative References

   [1]  Hinden, R. and S. Deering, "Internet Protocol Version 6 (IPv6)
        Addressing Architecture", RFC 3513, April 2003.

   [2]  Abley, J., Black, B. and V. Gill, "Goals for IPv6
        Site-Multihoming Architectures", RFC 3582, August 2003.

   [3]  Johnson, D., Perkins, C. and J. Arkko, "Mobility Support in
        IPv6", draft-ietf-mobileip-ipv6-24 (work in progress), July
        2003.

   [4]  Nordmark, E. and T. Li, "Threats relating to IPv6 multihoming
        solutions", draft-nordmark-multi6-threats-00 (work in progress),
        October 2003.




































Lear                     Expires June 10, 2004                  [Page 9]


Internet-Draft        MULTI6 Solution Questionaire         December 2003


Informative References

   [5]  Kitamura, H., "A SOCKS-based IPv6/IPv4 Gateway Mechanism", RFC
        3089, April 2001.


Author's Address

   Eliot Lear
   Cisco Systems
   170 W. Tasman Dr.
   San Jose, CA  95134-1706
   US

   EMail: lear@cisco.com




































Lear                     Expires June 10, 2004                 [Page 10]


Internet-Draft        MULTI6 Solution Questionaire         December 2003


Intellectual Property Statement

   The IETF takes no position regarding the validity or scope of any
   intellectual property 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; neither does it represent that it
   has made any effort to identify any such rights. Information on the
   IETF's procedures with respect to rights in standards-track and
   standards-related documentation can be found in BCP-11. Copies of
   claims of rights made available for publication 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 implementors or users of this specification can
   be obtained from the IETF Secretariat.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights which may cover technology that may be required to practice
   this standard. Please address the information to the IETF Executive
   Director.


Full Copyright Statement

   Copyright (C) The Internet Society (2003). All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works. However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assignees.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION



Lear                     Expires June 10, 2004                 [Page 11]


Internet-Draft        MULTI6 Solution Questionaire         December 2003


   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.


Acknowledgment

   Funding for the RFC Editor function is currently provided by the
   Internet Society.











































Lear                     Expires June 10, 2004                 [Page 12]