Re: [BEHAVE] FYI: draft-despres-sam-02 enclosed

[Margaret Wasserman <[e-mail]>]

Hi Remi,

I have a few high-level comments/questions on this draft from my first  
reading, and I may have more after I have reviewed it in more detail.

(1) You have indicated that you would like to discuss this draft in  
the 6AI BOF, but you have not cc:ed the mailing list for the 6AI BOF ([e-mail] 
).  Also, have you talked to the chairs of the 6AI BOF (Bob Hinden and  
Dan Wing) about whether they are willing to include this draft on the  
agenda, despite the fact that it has not been posted to the I-D  
archive?  There doesn't appear to be an agenda online for the 6AI BOF  
yet, so I am not sure if it will be included.

(2) The end hosts in the SAM system need to know their globally  
routable addresses, so how can SAM be said to provide address  
independence?

(3) Exactly what formulation of the end-to-end principle are you  
referring to in this paper when you indicate that SAM preserves it in  
IPv6?

My understanding of the end-to-end principle is that it has to do with  
putting intelligence at the edges of the network (in hosts vs. routers/ 
middleboxes) and with putting certain function at the top of the  
protocol stack (apps layer vs. lower layers).  This is based on my  
understanding (and recollection) of a paper by Jerry Saltzer, D. Reed  
and Dave Clark written in the mid 1980s, which you can find here:

http://web.mit.edu/Saltzer/www/publications/endtoend/endtoend.txt

It is also reasonably well-summarized in this Wikipedia article.

http://en.wikipedia.org/wiki/End-to-end_principle

Based on my understanding of the end-to-end principle, I don't see any  
significant difference in SAM vs. NAT66 WRT how much they maintain (or  
violate) the end-to-end principle, as both mechanisms place some  
functions/intelligence in the infrastructure.

Margaret



On Mar 13, 2009, at 5:56 AM, Rémi Després wrote:

> Hi,
> For your information, draft-despres-sam-02, which was ready too late  
> to be posted before IETF 74, is enclosed below
>
> It is a major update of the version-01 which was presented at IETF 73:
> - In Softwires, ref.:
> http://www.ietf.org/proceedings/08nov/slides/softwire-3/softwire-3_files/slide0002.htm
> - In Behave, ref.:
> http://www.ietf.org/proceedings/08nov/slides/behave-15.pdf
>
> In San Francisco, its part that deals with NAT66 avoidance is to be  
> discussed at the 6IA BOF meeting (ex NAT66).
> Its part that deals with Port-Range extension, is to be discussed at  
> the SHARA BOF.
>
> Comments most welcome.
>
> Regards,
>
> RD
>
>
>
>
>
>
> Internet Engineering Task Force                               R.  
> Despres
> Internet-Draft                                             November  
> 2008
> Intended status: Standards Track
> Expires: May 5, 2009
>
>
>                     Stateless Address Mapping (SAM)
>       Avoiding NATs and restoring the end-to-end principle in IPv6
>                           draft-despres-sam-02
>
> 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 May 5, 2009.
>
> Abstract
>
>    Stateless Address Mapping (SAM) is a generic mechanism to support
>    global addressing across network zones where routing is based on a
>    different address space.  With it, the end-to-end principle, lost  
> in
>    IPv4 with the deployment of NATs, can be restored without losing
>    services that NAT44s offer beyond address-space extension (private
>    addressing, basic firewall, site multihoming, privacy protection,
>    host-rooted subnets).  Global-address packets are encapsulated in
>    local-address packets to traverse SAM zones, and global prefixes  
> are
>    statelessly mapped into local addresses.  For the IPv6-IPv4
>    coexistence period, port-restricted IPv4 addresses are used to  
> extend
>    the global IPv4 address space.
>
>
>
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> Internet-Draft     Stateless  Address  Mapping  (SAM)      November  
> 2008
>
>
> Table of Contents
>
>    1.  Introduction and general problem  
> statement . . . . . . . . . .  3
>    2.  NAT44 services availability of which in IPv6 is  
> desirable  . .  4
>      2.1.  Private addressing (easy  
> renumbering)  . . . . . . . . . .  4
>      2.2.  Basic firewall (by default, no incoming  
> connections) . . .  4
>      2.3.  Site multihoming (automatic  
> fallback)  . . . . . . . . . .  4
>      2.4.  Privacy  
> protection . . . . . . . . . . . . . . . . . . . .  4
>      2.5.  Host-rooted  
> subnets  . . . . . . . . . . . . . . . . . . .  5
>    3.  SAM  
> specification  . . . . . . . . . . . . . . . . . . . . . .  5
>      3.1.  Local Zones - Root SAMs - Branch  
> SAMs  . . . . . . . . . .  5
>      3.2.  Encapsulation of global packets in local  
> packets . . . . .  7
>      3.3.  Global prefixes - global addresses - local  
> addresses . . .  9
>      3.4.  Endpoint global address to branch local address  
> mapping  . 11
>      3.5.  Privacy  
> protection . . . . . . . . . . . . . . . . . . . . 13
>      3.6.  SAM  
> parameters . . . . . . . . . . . . . . . . . . . . . . 15
>      3.7.  Port-range-based extended IPv4  
> addressing  . . . . . . . . 16
>    4.  SAM Application  
> examples . . . . . . . . . . . . . . . . . . . 17
>      4.1.  Address independence in an IPv6  
> site . . . . . . . . . . . 17
>      4.2.  Multihoming and extended IPv4 addressing in a home  
> site  . 19
>    5.  SAM as an alternative to NATs in  
> IPv6  . . . . . . . . . . . . 21
>    6.  Security  
> considerations  . . . . . . . . . . . . . . . . . . . 22
>    7.  IANA  
> Considerations  . . . . . . . . . . . . . . . . . . . . . 22
>    8.   
> Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 23
>    9.   
> References . . . . . . . . . . . . . . . . . . . . . . . . . . 23
>      9.1.  Normative  
> References . . . . . . . . . . . . . . . . . . . 23
>      9.2.  Informative  
> References . . . . . . . . . . . . . . . . . . 23
>    Author's  
> Address . . . . . . . . . . . . . . . . . . . . . . . . . 25
>    Intellectual Property and Copyright  
> Statements . . . . . . . . . . 26
>
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>
> 1.  Introduction and general problem statement
>
>    In IPv4, Network Address Translations have been extensively  
> deployed
>    (NAT44s).  They are key to mitigate the IPv4 address shortage.  But
>    they also offer various auxiliary services, described in Section 2:
>    private addressing, basic firewall, site multihoming, privacy
>    protection, host-rooted subnets.
>
>    In counterpart to these auxiliary services, these NAT44s have
>    introduced two drawbacks:
>
>    o  Non compliance with the end-to-end principle of the Internet
>       (e2e).
>
>          Negative consequences include incompatibility with the IPsec
>          security mechanism, and difficulties for hosts to know their
>          own global addresses, which they need for connection
>          redirections, for host referrals, and and, in sites having
>          several site entrance routers, for multihoming support
>          mechanisms like the SCTP of [RFC4960] and [Shim6].
>
>    o  Stateful operation.
>
>          Most NAT44s are in fact stateful NAPTs (ref. < xref
>          target="RFC2663" />): to support more local addresses than  
> they
>          have external addresses, they maintain per-transport- 
> connection
>          states.  Negative consequences include limited scalability,  
> and
>          the risk of denial of service attacks that go with it, as  
> well
>          as single points of failures.
>
>    Since no global address shortage is in view in IPv6, the following
>    questions have to be asked:
>
>    o  Which NAT44 services can, in IPv6, be offered statelessly and
>       without breaking the e2e principle?
>
>    o  How?
>
>    This draft proposes to answer these questions more completely, and
>    with more technical details, than [RFC4864], the most advance
>    document on the subject so far.
>
>    For this, a Stateless Address Mapping generic mechanism is  
> introduced
>    (SAM).
>
>    Conclusion, is that, provided SAM is supported in nodes at  
> borders of
>    independently administered routing zones, the e2e principle can be
>    restored in IPv6, for all identified useful functions of NAT44s.
>
>
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>    (This conclusion needs however to be confirmed after further work  
> on
>    SAM details, after criticisms by other experts, after some possible
>    bug corrections, and after validations with running code.)
>
>    Thus, traversal of NATs in ISP infrastructures can be avoided.
>    (These NATs do provide useful connectivity to some non-SAM-capable
>    nodes, but have the drawback of breaking the e2e principle, with  
> the
>    mentioned consequences on security, referrals, multihoming,
>    scalability and reliability.
>
>
> 2.  NAT44 services availability of which in IPv6 is desirable
>
> 2.1.  Private addressing (easy renumbering)
>
>    With NAT44s, when a prefix assigned by an ISPs to a customer site  
> is
>    modified, local IP addresses in the site can remain unchanged.
>
> 2.2.  Basic firewall (by default, no incoming connections)
>
>    Most NAT44s, being NAPTs, and therefore maintaining states for all
>    TCP and UDP connections, have as a byproduct a protection against
>    incoming connections (unless some "holes" are "punched" in this
>    protection, under explicit customer control).  This level of  
> security
>    protection is largely relied upon.
>
> 2.3.  Site multihoming (automatic fallback)
>
>    In a site is multi-homed, and if it has a NAT device supporting all
>    its ISP interfaces, its hosts can take advantage of multihoming
>    without having to support any multihoming-specific function.  This
>    level of multihoming support is better than none.
>
>    (For this, a NAT44 needs only to make sure that, for each transport
>    connection, all outgoing packets go through the same ISP.  Thus, if
>    an ISP access fails, current TCP and UDP connections that go via  
> this
>    ISP are broken, but theycan immediately be replaced by new ones.)
>
> 2.4.  Privacy protection
>
>    From outside a site where a NAT44 operates in NAPT mode, it is
>    difficult to determine which hosts establish which connections.   
> This
>    level of privacy protection, in particular for some web requests,  
> is
>    an added value.
>
>
>
>
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> 2.5.  Host-rooted subnets
>
>    Behind a host that is assigned a single IPv4 address, it is  
> possible,
>    with a NAT44 in the host, to deploy a private subnet.  As modern
>    operating systems include a router function with a NAT44, a  
> computer
>    can can serve as a root for a LAN.
>
>    Thus, the distinction between hosts and a routers is no longer a
>    distinction between types of devices.  It has become only a
>    distinction between functions within nodes.
>
>
> 3.  SAM specification
>
> 3.1.  Local Zones - Root SAMs - Branch SAMs
>
>    As presented in Figure 1, the SAM mechanism applies to a SAM "local
>    zone" Z. Routing within this zone is independently administered,  
> and
>    is based on a "local address space".
>
>    Each SAM zone has one or several "root interfaces" (Ri), that give
>    access to the global Internet.  Each one has, in the global  
> Internet,
>    one or several "global prefixes" (gZij) exclusively assigned to  
> zone
>    Z.
>
>    SAM global prefixes can be global IPv6 and/or global IPv4.  SAM  
> local
>    address spaces can be IPv6 or IPv4, global or private.  If both  
> IPv4
>    and IPv6 are routed in the zone, one of the two is chosen for SAM.
>    (SAM is in this respect therefore an extension of the 6to4 of
>    [RFC3056], of the ISATAP of [RFC5214], and of [6rd], where all  
> global
>    prefixes are IPv6 and all local address spaces are IPv4).
>
>    As explained in Section 3.7, global IPv4 addresses can be extended
>    beyond 32 bits to deal with the IPv4 address shortage during the
>    IPv4-IPv6 coexistence period.
>
>
>
>
>
>
>
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>                                          ROOT-SIDE ENDPOINTS
>                                       |         /\            |
>                                       |         ||            |
>                                 |_____:_____|   ||     |______:_____|
>                                       |                       |
>                                       |      ROOT ZONES       |
>                                       |                      gZ22
>     Zone Global prefixes gZij       gZ11                     gZ21
>     Root interfaces:          
> _________:_______________________:________
>                             |(Z)   (root-SAM)              (root- 
> SAM)  |
>     Root local addresses:   |         R1                        
> R2      |
>             Ri               
> |                                          |
>                             |                SAM ZONE  
> Z                |
>                              
> |                                          |
>                              
> |                                          |
>     Branch local addresses: |      B1               B2            
> B3   |
>             Bk               
> |      :                :             :    |
>     Branch interfaces:      | 
> ______:________________:_____________:____|
>                                    |                |             |
>     Branch Global prefixes:        |          (branch-SAM)        |
>       *gBkij=gZij.zBk*               => + gB211, gB221, gB222
>     Branch Global Addresses:            +  gB211@, gB221@, gB222@
>       *gBkij@=gBkij.H*                              ||
>                                BRANCH ZONES         ||
>                                                     \/
>                                           BRANCH-SIDE ENDPOINTS
>
>                       ROOT AND BRANCH INTERFACES AND SAMs
>
>                                  Figure 1
>
>    Each root interface that supports a root-SAM function has a local
>    address (Rk), and each "branch interface" has a local address (Bk).
>
>    If a "branch SAM" function is supported at a branch interface Bk,
>    this interface gets, in addition to its local address, global
>    prefixes (gBkij).  Each of these prefixes is made of a global  
> prefix
>    of the zone (gZij) followed by an identifier (zBk) of the branch in
>    its zone.
>
>    For each each of its global prefixes gBkij, a branch interface has
>    also a host global address (gBkij@), derived from the prefix by
>    appending a standard host suffix (H) to complete the address  
> length.
>
>    Thus, if a zone D is accessible from the global Internet via a zone
>    hierarchy A, B, C, it has at least gA.aB.bC.cD as a global prefix  
> gD,
>    and gA.aB.bC.cD.H as a global address gD@.  SAM is thus an
>    application of the locator-identifier separation principle.  (It
>
>
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>    differs however from [LISP], in that no new protocol is needed fro
>    SAM, just new options in existing protocols such as DHCP [RFC2131],
>    DHCPv6 [RFC3315], or ND [RFC4861], to advertise SAM parameters to
>    branch interfaces.)
>
> 3.2.  Encapsulation of global packets in local packets
>
>
>    endpoint Y Global address:                 gY
>                                                ^
>                                                |
>                                               ...
>    (3)  e2e packet:                    [ gX->gY [data]]
>                                                ^
>                                                |
>                                               gZ         ROOT ZONE R
>                                  ______________:______________________
>                                 |(Z)       (root  
> SAM)                 |
>                                 |              R         LOCAL ZONE  
> Z |
>                                 |               
> ^                      |
>                                 |               
> |                      |
>                                  
> |             ...                     |
>    (2)  encapsulated packet:     
> |                                     |
>          *B = la(gX)*           |      [  B->R [gX- 
> >gY[data]]         |
>          *R = parameter*        |               
> ^                      |
>                                 |               
> |                      |
>                                 |               
> B                      |
>                                 | 
> ______________:______________________|
>                                           (branch SAM)   BRANCH ZONE B
>                                            => + gB
>                                                ^
>                                                |
>                                               ...
>    (1)  e2e packet:                    [ gX->gY [data]]
>                                                ^
>                                                |
>    endpoint X Global address:          gX=gZ.id(B).xxx
>
>
>      PACKET ENCAPSULATION AND ADDRESS MAPPING - BRANCH SIDE TO ROOT  
> SIDE
>
>                                  Figure 2
>
>    To traverse a SAM local zone, global-address packets are  
> encapsulated
>    into local address packets, as illustrated in Figure 2 and Figure  
> 3).
>
>    Thus, compatibility is ensured, within the local zone, with ingress
>    the filtering for multihomed networks of [RFC3704], the basic anti-
>
>
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>    spoofing mechanism.
>
>
>                                                |
>                                                |           ROOT ZONE
>                                               gZ
>                                  ______________:______________________
>                                 |(Z)       (root- 
> SAM)                 |
>                                 |              R         LOCAL ZONE  
> Z |
>                                  
> |                                     |
>                                  
> |                                     |
>                                  
> |                                     |
>    (2)  encapsulated packet:    |     [ B1->B2 [gE1- 
> >gE2[data]]       |
>         *B1 = la(gX)*           |         -------- 
> >--------           |
>         *B2 = la(gY)*           |       /                    
> \         |
>                                 |      ^                      
> |        |
>                                 |      |                      
> v        |
>                                 |      B1                     
> B2       |
>                                 | 
> ______:_____________________:________|
>            BRANCH ZONES:          (branch-SAM)          (branch-SAM)
>                                     => + gB1              => + gB2
>                                        ^                     |
>                                        |                     v
>    (3)  e2e packet:                   ...              [ E1->E2  
> [data]]
>    (1)  e2e packet:             [ E1->E2 [data]]             ...
>                                        ^                     |
>                                        |                     v
>                                gX=gZ.id(B1).xxx          
> gY=gZ.id(B2).yyy
>                                       _:_                   _:_
>                                      | X |                 | Y |
>                                      |___|                 |___|
>
>    ADDRESS MAPPING AND PACKET ENCAPSULATION - BRANCH SIDE TO BRANCH  
> SIDE
>
>                                  Figure 3
>
>    For the IP-in-IP encapsulation, the IPv6 next header or the IPv4
>    protocol id which indicates the type of IP payload is set to 41  
> (the
>    same value as for 6to4, ISATAP, and 6rd).
>
>    Local addresses are determined as follows (illustrated in figures
>    Figure 2 and Figure 3):
>
>    1.  If an endpoint global address gE, indifferently source or
>        destination, is that of a branch-side endpoint, this is
>        recognized by the fact that it starts with one of the global
>        prefixes of the zone.  Then, the local address B is obtained  
> by a
>        function B=la(gX), completely determined by SAM parameters of  
> the
>
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>        zone (details in Section 3.4).
>
>    2.  If an endpoint global address gE, indifferently source or
>        destination, is that of a root-side endpoint, this is  
> recognized
>        by the fact that it doesn't start with any of the global  
> prefixes
>        of the zone.  In this case, the other address gX of the packet,
>        destination or source respectively, is necessarily that of a
>        branch-side endpoint (otherwise the packet would not traverse  
> the
>        local zone).  Then, local address Ri is that of the root
>        interface that has, in its assigned global prefixes, the global
>        prefix present at the beginning of the branch-side address gX.
>
>    In multihomed sites, the second of these rules ensures  
> compatibility
>    with the ingress filtering of [RFC3704] in root zones (if it does
>    apply, as necessary for anti-spoofing protection).
>
>    In Figure 2 and Figure 3, packets in the reverse direction, not
>    shown, would have the same addresses but with sources and
>    destinations inverted, and with encapsulations and decapsulations
>    made at inverted interfaces.
>
>    Decapsulation functions MUST verify, for anti-spoofing protection,
>    that local addresses present in headers of encapsulating packets  
> are
>    consistent with global addresses present in headers of encapsulated
>    packets.
>
> 3.3.  Global prefixes - global addresses - local addresses
>
>    Internal structures of SAM global prefixes, global addresses, and
>    local addresses are detailed in Figure 4.
>
>    A branch-interface global prefix necessarily starts with a global
>    prefix of the zone Z. Its remaining bits are a "branch  
> identifier" in
>    the zone (gBkij = gZij.zB).
>
>
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>              |<-------------- Branch global address gB@ ------------- 
> >|
>              |<-------- Branch global prefix gB -------- 
> >             |
>              |<-- G --><-----  Branch identifier iB ---- 
> >             |
>               ________________________________________________________
>              |  local  |branch|  Subnet |     branch     |    
> branch   |
>              |  zone   |  id  |  index  |      Index     |     
> Host    |
>              |  Global |Format| (option)|                |   
> endpoint  |
>              |  prefix | code |         |                |    
> suffix   |
>              |         |      |         |                |  
> (10...00)  |
>              |    G    |   F  |    S    |        I       |      
> H      |
>              |_________|______|_________|________________| 
> ____________|
>                     _______/   <-- s ---><----- i ------>
>                   /               ^                    ^
>                  v                |                    |
>         Specifies s and b        /                      \
>           (option)              |                        \
>         Specify F   <-----.-----|--------------------.    \
>                            \    |                     \    |
>                             \   v                      \   v
>                            <-- s --->                 <----- i ------ 
> >|
>               ________________________________________________________
>              |local-address| Subnet  |  next field   |      
> branch     |
>              |   constant  |  index  |   Delimiter   |       
> index     |
>              |    Prefix   |         |   (00...01)    
> |                |
>              |             |         |                
> |                |
>              |       P     |    S    |      D        |         
> I       |
>              |_____________|_________|_______________| 
> ________________|
>              |<-- subnet prefix zS -->
>              |<-------------- Branch local address B ---------------- 
> >|
>
>
>          SAM GLOBAL PREFIXES - GLOBAL ADDRESSES - LOCAL ADDRESSES
>
>                                  Figure 4
>
>    Principles that influence the internal structure of branch
>    identifiers proposed for SAM are the following:
>
>    1.  To permit a flexible hierarchy of local zones, branch  
> identifiers
>        should be kept rather short.  They should, at least to some
>        extent, be proportionate to the maximum number of branches
>        supported in their zone.
>
>    2.  Several subnets must be possible in the zone.  For this, a  
> branch
>        identifier contain an optional "subnet index" (S), followed the
>        "branch index" (I) which identifies the branch in its subnet.
>        (The word "index" is chosen to express that these fields have  
> no
>        further internal structure.)
>
>
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>    3.  For the efficiency of routing tables, intra-zone subnet indexes
>        have to be in the upper part of local addresses, just behind  
> the
>        "constant prefix" (P) that is common to all local addresses.   
> (In
>        IPv6, this constant prefix can typically be an ULA prefix of
>        [RFC4193]; in IPv4 is typically a private-address prefix of
>        [RFC1918].)
>
>    4.  For efficiency of the neighbor discovery protocol of [RFC2461],
>        branch indexes B have on the contrary to be in the lowest  
> part of
>        branch local addresses B.
>
>    5.  Consequently, it must be possible to extract separately, from a
>        intra-zone branch identifier iB, the subnet index S and the
>        interface index I, and for this to know their lengths (s and  
> i).
>
>    6.  In order to permit to configure several subnet-index lengths,
>        and/or several interface index lengths, in SAM zones, an  
> optional
>        branch-identifier "format code" (F) is placed at the  
> beginning of
>        branch identifiers B (just before the optional subnet index S,
>        and the branch index B).  Each format codes specifies a subnet-
>        index length s and an interface-index length i.  Format codes T
>        may have different lengths, but must be non overlapping  
> prefixes
>        to be recognized.
>
>    Since the local address B of a branch interface starts with a
>    constant prefix P followed by the interface subnet index S , and is
>    terminated by the interface-index of the interface, space is left
>    between them.  It is filled with a next-field delimiter (D).  Its
>    format, a series of 0s followed by a 1, i.e. 00...01 with a minimal
>    length of 1 bit, is chosen so that knowing the constant prefix P  
> and
>    the subnet prefix of a branch interface, lengths s and i of the its
>    subnet index S and of its interface index I can be determined.   
> Then,
>    the identifier format F to be placed in global prefixes of B can be
>    derived from these lengths s and i.
>
> 3.4.  Endpoint global address to branch local address mapping
>
>    Detailed steps by which a branch local address B is derived from  
> from
>    the global address of a branch-side endpoint are presented in
>    Figure 5.
>
>
>
>
>
>
>
>
>
>
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>
>               ________________________________________________________
>              |                  Endpoint Global  
> address               |
>              |                              
> gE                         |
>              | 
> ________________________________________________________|
>                            (A) ANALYSIS    ||
>                                            \/
>               ___________________________________________ ............
>              | Global  |  id  |  Subnet |     branch     |  
> endpoint   :
>              | prefix  |Format|  index  |      Index     |   
> suffix    :
>              |    G    |   F  |    S    |        I       |      
> E      :
>              |_________|______|_________| 
> ________________|............:
>                        |   |       |            |
>      1. Match found    |   |       |            |
>      in the G list  ___|   |       |            |
>                            |       |            |
>      2. Match found        |       |            |
>      in the F list   ______|       |            |
>                                    |            |
>      3. length defined by F _______|            |
>                                    .            |
>      4. length defined by F ____________________|
>                                    .            .
>                  (B) CONSTRUCTION  .     ||     .
>                                    .     \/     .
>      5. The current                .            .
>      local-address prefix __       .            .
>                             |      .            .
>      6. From step 3. _______:______.__          .
>                             |         |         .
>      7. From step 4. _______:_________:_________.__________
>                             |         |                    |
>      8. Binary 00...01 _____:_________:________            |
>                             |         |        |           |
>               ______________|_________|________|___________|__________
>              |  local-address  | Subnet  |next field |      
> branch     |
>              |     Prefix      |  index  | Delimiter |       
> Index     |
>              |         P       |    S    |    D      |         
> I       |
>              |_________________|_________|___________| 
> ________________|
>              |<--------------- Branch Local address B --------------- 
> >|
>
>         DERIVING A BRANCH LOCAL ADDRESS FROM AN ENDPOINT GLOBAL  
> ADDRESS
>
>                                  Figure 5
>
>
>
>
>
>
>
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>
> 3.5.  Privacy protection
>
>    In a zone where privacy protection is desired, the privacy option  
> can
>    be turned on.  Principles of this option are the following:
>
>    o  Fields that identify branch-side IP endpoints in privacy  
> protected
>       zones, or transport endpoints if endpoints are at this layer,  
> are
>       obfuscated in e2e packets that traverse the the global Internet.
>
>    o  This obfuscation is stateless and reversible.
>
>    o  Branch SAMs of a privacy-protected zone are informed of  
> parameters
>       of this obfuscation.  They can thus know which "hidden"  
> addresses
>       (or addresses plus ports), appear on the global Internet in  
> place
>       of their "clear" addresses (or address plus ports).  These clear
>       addresses are those from which local addresses are derived in  
> the
>       privacy-protected zone and in zones that are lower in the
>       hierarchy.
>
>    o  In these lower zones, all branch SAMs are informed that a root  
> SAM
>       in the global-Internet direction has activated a privacy option,
>       and are informed of parameters of this option.  They can thus
>       derive a clear address (or address plus port) from an obfuscated
>       address (or address plus port), and conversely.  They can also
>       avoid to activate the privacy so that obfuscation is never done
>       more than once.
>
>    Parameters of a privacy option are a privacy global prefix (PPm)  
> and
>    a scrambling multiplier (PMm).  The prefix is that which, at the
>    beginning of global addresses, is not obfuscated in the global
>    Internet.  The multiplier is a 64 bit odd constant.
>
>    Obfuscation consists in a modulo 2^n multiplication by the  
> scrambling
>    multiplier, where n is the number of bits to be obfuscated.  De-
>    obfuscation is the modulo 2^n multiplication by the inverse of the
>    scrambling multiplier (for odd numbers, such an inverse modulo 2^n
>    always exists).
>
>    In hosts in which the branch SAM is informed of an active privacy
>    option, applications that ask for their address and their port at
>    their socket interface, get them in hidden form, that which appears
>    in the global Internet.  The e2e principle is thus preserved  
> despite
>    the fact that the topology of the privacy-protected zone and that  
> of
>    lower zones in the hierarchy are all hidden, and despite the fact
>    that successive transport connections from a same host cannot, in  
> the
>    global Internet, be related to a single host.
>
>    Ports that are concerned with the privacy option are only the IANA
>
>
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>
>    defined dynamic and/or private ports (ports 49152 to 65535, those
>    starting with binary 11).  Well known ports and registered ports,
>    which have an e2e meaning not to be lost must not be obfuscated.
>
>    Since some applications, e.g. active mode FTP of [RFC0959], work on
>    port pairs rather than on individual ports, port bits to be
>    obfuscated must exclude the las one.  Port bits that are part of
>    obfuscated endpoint identifiers are then bits 2 to 14.
>
>
>
>                                             gY
>                                              ^
>                                              |
>                                             ...
>     e2e packet:              gZ11.F2.hhhh->gY [TCP hh->80 [data]]
>                                              ^
>                                              |
>                                            gZkij         ROOT ZONE R
>                   ___________________________:________________________
>                  |(Z)             .--> (root  
> SAM)                     |
>     Privacy-option ON            /            
> Rk                       |
>     for prefix PP1 = gZkij.F1 ---'           ^          LOCAL ZONE  
> Z  |
>     with multiplier PM1                       
> |                        |
>                  |                            
> |                        |
>                   
> |                          ...                       |
>     encapsulated |   [ B->R [ gZkij.cccc->gY [TCP cc->80  
> [data]]      |
>        packet     
> |                                                    |
>                  |                            
> ^                        |
>                  |                            
> |                        |
>                  |                            
> B                        |
>                  | 
> ___________________________:________________________|
>                                         (branch SAM)
>     Clear-address packet:        gZkij.F1.cccc->gY [TCP cc->80 [data]]
>     e2e packet:                  gZkij.F1.hhhh->gY [TCP hh->80 [data]]
>        where tmp = modulo 2^m (PM1 x (cccc . (bits 2 to 14 of cc))
>                    where m = length of cccc + length of cc - 3
>              hhhh = bits 0 to (length of hhhh - 1) of tmp
>              hh = cc in which bits 2-15 are replaced by
>                   bits(length of PP1 TO m - 1) of tmp .
>
>                            SAM PRIVACY OPTION ILLUSTRATION
>
>                                  Figure 6
>
>    Figure 6 illustrates the effect of the privacy option.  The  
> option is
>    supposed to be on, in the root SAM of the zone, for its global  
> prefix
>    gZkij and its identifier format F1.  The privacy-option prefix is
>
>
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>    therefore PP1 = gZ11.F2. the scrambling multiplie ris PM1.
>
> 3.6.  SAM parameters
>
>    Table 3 to Table 5 of this section present the complete set of SAM
>    parameters described in previous sections.
>
>                       +-----------------------+-----+
>                       | constant local Prefix | TTL |
>                       +-----------------------+-----+
>                       |          ...          | ... |
>                       |           Pm          | PTm |
>                       |          ...          | ... |
>                       +-----------------------+-----+
>
>                         CONSTANT PREFIX PARAMETERS
>
>                                   Table 1
>
>    +--------------------+-----+------------------ 
> +---------------------+
>    |  identifier Format | TTL |   Subnet-index   |   Interface- 
> index   |
>    |        code        |     |      Length      |         
> Length       |
>    +--------------------+-----+------------------ 
> +---------------------+
>    |         ...        | ... |        ...        
> |         ...         |
>    |         Fn         | FTn |        SLn       |          
> ILn         |
>    |         ...        | ... |        ...        
> |         ...         |
>    +--------------------+-----+------------------ 
> +---------------------+
>
>                        IDENTIFIER-FORMAT PARAMETERS
>
>                                   Table 2
>
>    +-----------------+-----+---------------+-----+--------------- 
> +-----+
>    |    Root local   | TTL | Global Prefix | ... | Global Prefix  
> | ... |
>    |     address     |     |       1       |     |       j        
> |     |
>    +-----------------+-----+---------------+-----+--------------- 
> +-----+
>    |       ...       | ... |      ...      | ... |      ...       
> | ... |
>    |        Ri       | RTi |      gZi1     | ... |      gZij      
> | ... |
>    |       ...       | ... |      ...      | ... |      ...       
> | ... |
>    +-----------------+-----+---------------+-----+--------------- 
> +-----+
>
>                               ROOT PARAMETERS
>
>                                   Table 3
>
>
>
>
>
>
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>                        +--------------------+------+
>                        | Global zone prefix |  TTL |
>                        +--------------------+------+
>                        |         ...        |  ... |
>                        |        gZij        | GTij |
>                        |         ...        |  ... |
>                        +--------------------+------+
>
>                          GLOBAL-PREFIX PARAMETERS
>
>                                   Table 4
>
>         +-----------------------+-----+---------------------------+
>         | Privacy-option Prefix | TTL | Privacy-option Multiplier |
>         +-----------------------+-----+---------------------------+
>         |          ...          | ... |            ...            |
>         |          PPp          | PTp |            PMp            |
>         |          ...          | ... |            ...            |
>         +-----------------------+-----+---------------------------+
>
>                          PRIVACY-OPTION PARAMETERS
>
>                                   Table 5
>
> 3.7.  Port-range-based extended IPv4 addressing
>
>    For a dual stack host not to break the e2e principle when it
>    establishes a connection with an remote endpoint that is still only
>    reachable in IPv4, it must have a global IPv4 address.  Because of
>    the IPv4 address shortage, this address may however be shared with
>    other hosts.  For this, SAM accepts "port-extended" IPv4 prefixes,
>    longer than 32 bits.  Bits beyond the first 32 define a port  
> range in
>    the set of dynamic and/or private ports (those in which the two  
> high
>    order bits are binary 11).  For example, a 3-bit prefix extension  
> 010
>    imposes that branch-side hosts use only ports starting with binary
>    11010.
>
>    Note that, due to the systematic encapsulation of global packets in
>    local packets of SAM, routing within SAM zones is not concerned  
> with
>    theses "port-extended" IPv4 addresses.  Only root SAMs and branch
>    SAMs have to know about of port ranges.
>
>    The branch SAM in a host that is assigned a port-restricted IPv4
>    address has to inform its socket interface of the port range
>    available to applications, and to inform its internal NAT if it has
>    one.  Consequences for applications, and for NATs, of restricted  
> port
>    ranges, are out of the scope of this SAM specification.  Other
>    documents are available on the subject, e.g.  [Boucadair], which
>
>
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>    however requires further study.
>
>
> 4.  SAM Application examples
>
> 4.1.  Address independence in an IPv6 site
>
>    In the example of Figure 7, we consider a home or SOHO site in  
> which
>    an Ethernet and/or WiFi LAN is deployed.  Its global IPv6 prefix gZ
>    is 2001:0db8:9999::/48.
>
>    Local addressing is done in an IPv6 private space.  To keep address
>    shorts in the figure, the constant prefix of these addresses is
>    fc00/8, the shortest prefix reserved for private IPv6 addressing in
>    [RFC4193].  (This prefix could however be replaced by a full fdxx:
>    xxxx:xxxx::/48 prefix, as recommended in [RFC4193] for ULAs,  
> without
>    changing the substance of the example.)
>
>    The site is configured to support 255 branch interfaces on the LAN
>    (each branch being indifferently a host and/or a router).  To
>    facilitate future changes, a branch-identifier format code F1,  
> set to
>    0/4, is used in branch global prefixes.
>
>    SAM parameters of the site are then following (ignoring TTLs):
>
>       Constant local prefix: P1 = fc00/8
>
>       Identifier format code: F1 = 0::/4
>
>       Subnet index length: SL1 = 0 (non applicable)
>
>       Interface index length: IL1 = 8
>
>       Root local address: R1 = fc00::0101
>
>       Zone Global prefix: gZ11 = 2001:0db8:9999::/48
>
>       Privacy option prefix: none in this example
>
>    We now consider a SAM-capable PC which serves as a router for a
>    bluetooth link.  On this link, a bluetooth mobile phone is active.
>    (Configuring a root-SAM in the PC would permit the mobile phone, if
>    acting as a SAM-capable router, to assign global prefixes and
>    addresses, to hosts behind it.  But this would have been too much  
> for
>    the example).
>
>
>
>
>
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>                                           |
>                                           |
>                                   2001:0db8:9999::/48
>                          _________________:_________________
>                         |(Z)       (root SAM) for 2^8 hosts |
>                 Site    |            fc00::0101             |
>                gateway  |                                   |
>                         |                                   |
>                         |            fc00::0155             |
>                         |_________________:_________________|
>                                           |
>                  Ethernet and/or WiFi    ...
>                       fcOO::/64           |
>
>                                       fc00::0155
>                                      (branch SAM)
>                              => +  2001:0db8:9999:0550::/60
>                                 __________:__________
>                                |2001:0db8:9999:0558::|
>                PC              |                     |
>                                |_____________________|
>                               /___________._________/
>                                           |
>                   Bluetooth              ...
>                2001:0db8:9999:0550::/64   |
>                                           |
>                             2001:0db8:9999:0550:< eui64 IID >
>                                           |
>                                         |_|__
>                                        |     |
>                Mobile phone            |     |
>                                        |     |
>                                        |_____|
>
>                                  Figure 7
>
>    The PC local address B is fc00::0155, i.e.  P.D.I where P is
>    fc00::/8, where the 8 bits of I are supposed to be 55::/8, and  
> where
>    D is binary 00...01 with consequently (128 - 8 -8) = 112 bits.
>
>    The PC global prefix gB is therefore 2001:0db8:9999:0550::/60, i.e.
>    G.F.I, where G is 2001:0db8:9999::/48, where F is 0::/4, and  
> where I
>    is 55::/8.
>
>    The PC global address is therefore 2001:0db8:9999:0558::, i.e. gB.E
>    where E is binary 10...00 with (128 - 48 - 4 - 8) = 68 bits.
>
>    The bluetooth link is supposed to have 0::/4 as subnet ID in the  
> PC.
>
>
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>    Its /64 subnet prefix is therefore 2001:0db8:9999:0550::/64.
>
>    This simple example illustrates how the SAM logic permits to
>    establish a hierarchy of routing zones where each host can become a
>    router, and where the e2e principle is preserved.
>
> 4.2.  Multihoming and extended IPv4 addressing in a home site
>
>    In the example of Figure 8, we consider a home site S, multihomed
>    with two ISPs A and B.
>
>    ISP A assigns to the site IPv6 prefix 2001:1111:1111:1110::/60, and
>    IPv4 address 192.0.2.1.
>
>    ISP B can only assign port-restricted IPv4 addresses to its sites
>    because it has to support up to 2^16 sites, and has only for this  
> an
>    IPv4 /18 prefix (namely 198.16.0.0/18, i.e. v4|c610:0000:/18), and
>    since 18 + 16 = 34 which exceeds 32.  Having 2001:0db8::/32 as its
>    IPv6 prefix, it assigns /48s to its customer sites, in particular
>    2001:0db8:0202::/48 to site S.
>
>    Half of its IPv4 address space, namely v4|c608:c000/19 is allocated
>    to a NAT to support sites that are not SAM capable.  The other  
> half,
>    i.e. v4|c610:2000/19, is allocated to a root SAM, the local address
>    of which is supposed to be 2001:0db8::1.
>
>    SAM parameters of the zone of ISP B are then the following:
>
>       Constant local prefix: P1 = 2001:0db8: = v4|a000::/8
>
>       Identifier format code: F1 = ::/0 (non applicable)
>
>       Subnet index length: SL1 = 0 (non applicable)
>
>       Interface index length: IL1 = 16
>
>       Root local address: R1 = 2001:0db8::1:1
>
>       Zone Global prefix: gZ11 = v4|c608:8000/19 (=198.8.128.0/19).
>
>       Privacy option prefix: none in this example (::/0)
>
>
>
>
>
>
>
>
>
>
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>                                                       198.16.0.0/18
>                                 2001:0db8::/32       =v4|c610:0000:/18
>                                   ____|__________________|____________
>                                  |(B)             /             
> \      |
>                                  |               |    v4| 
> c610:2000/19 |
>                                  |          v4|c608:c000/19       
> |    |
>                                  |             (NAT)       (root  
> SAM) |
>                                  |         0.0.0.0/0      
> 2001:0db8::1 |
>      |(A)                     |   
> |                                    |
>      |                        |   
> |                                    |
>      |2001:1111:1111:1110::/60|  |   (2^16 SAM  
> sites)                 |
>      |       192.0.2.1        |   
> |                                    |
>      |      =v4|c000:0201/32  |  |       
> 2001:0db8:0202::/48           |
>      |________________:_______|  | 
> ___________________:________________|
>                       |                      (branch SAM)
>                       |           => + v4|c610:2040:4000::/35
>                       |              = 198.8.128.64/ports 11010...
>       ________________:______________________________:________________
>      |(S)     /               \               /               
> \        |
>      |       |     v4|c000:0201:0000::/33    |  v4| 
> c610:2040:4000::/36|
>      |       |                 ::/0          |                 ::/ 
> 0   |
>      | v4|c600:0201:8000::/33   |     v4|c608:2040:6000::/36     
> |     |
>      |     (NAT)            (root SAM)     (NAT)          (root  
> SAM)  |
>      |   0.0.0.0/0          fc00::0011    0.0.0.0/0        
> fc00::0012  |
>       
> |                                                                |
>      | (2^4 SAM  
> hosts)                                                |
>      |                         
> fc00::0018                              |
>      | 
> _____________________________:__________________________________|
>                                    |
>            HOST (H)           (branch SAM)
>                     => + 2001:1111:1111:1118:8000::0008/64
>                        + 2001:0db8:0220:4800::0008/52
>            + v4|c000:0201:4000::/37 = 192.0.2.1 ports 1101000...
>            + v4|c610:2040:5000::/40 = 198.16.32.64 ports 1101001000...
>                                   :
>                                   HOST
>
>        PRIVATE-ADDRESSING- AND DUAL-HOMING- SITE WITH E2E CAPABILITY
>
>                                  Figure 8
>
>    In site S, the branch SAM of its root interface with ISP B derives
>    from its IPv6 prefix 2001:0db8:O2O2::/48, and from SAM parameters  
> of
>    ISP B, its IPv4 prefix v4|c610:2040:4000::/35, which is a port-
>    restricted one.
>
>    Two root SAMs are configured in site S. Its local-address constant
>    prefix is fc00::/8 as.  Half of the each available IPv4 addressing
>
>
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>    space is reserved for a NAT, and the other half for a root SAM.
>
>    Parameters of SAMs of site S are then the following:
>
>       Constant local prefix: P1 = fc00/8
>
>       Identifier format code: F1 = 0::/4
>
>       Subnet index length: SL1 = 0
>
>       Interface index length: IL1 = 8
>
>       Root local addresses: R1 = fc00::0011; R2 = fc00::0012
>
>       Zone Global prefixes: gZ11 = 2001:1111:1111:1110::/60; gZ12 =  
> v4|
>       c000:0201/32; gz21 = 2001:0db8:0202::/48; gZ22 = v4|
>       c610:2040:4000::/35
>
>       Privacy option prefix: none in this example (::/0)
>
>    Among the 16 hosts of home site S, Host H is supposed to have local
>    address fc00::0018.  As shown on the figure, the branch SAM of  
> host H
>    then derives from this local address two IPv6 global prefixes, two
>    IPv6 global host addresses starting with these prefixes, and two
>    port-restricted IPv4 prefixes.  With these prefixes, it can use,
>    without breaking the e2e principle, 512 ports for connections via  
> ISP
>    A, and 64 ports via ISP B.
>
>
> 5.  SAM as an alternative to NATs in IPv6
>
>    With SAM as specified, all NAT44 services that have been listed in
>    Section 2 can be offered in IPv6 without stateful processing and
>    without breaking the e2e principle:
>
>    1.  In a private-addressing IPv6 site, hosts can know their global
>        addresses to use them in e2e packets that are encapsulated in
>        local packets to traverse the site.  Renumbering is then
>        automated simply by automating advertisement of SAM parameter
>        changes (in DHCP and/or with router advertisements).
>
>    2.  The fact that NAT44s are in general configured with by default
>        rejection of all incoming calls can have a simple stateless
>        equivalent in IPv6:
>
>        *  By default, reject all incoming packets that have a branch-
>           side port in the well known or in the IANA defined  
> registered
>           port ranges.
>
>
>
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>
>
>        *  By default, reject all TCP incoming packets that are  
> attempts
>           to open new incoming connections (SYN packets without ACK).
>
>    3.  In a SAM-capable site, SAM-capable hosts can take advantage of
>        site multihoming with full compatibility with ingress filtering
>        of [RFC3704] in both the site itself and in ISP networks to  
> which
>        it is connected.
>
>    4.  The privacy protection described in Section 3.5 maintains the  
> e2e
>        principle.  It is expected to be largely sufficient in  
> practice.
>        (Sophisticated hackers would probably find ways around it, and
>        identify who does what in sites havin the privacy-protection
>        option, but NAT44s are not perfect for privacy protection
>        either).
>
>    5.  As we have seen, SAM global addresses contain a flexible
>        succession of branch identifiers, so that it becomes possible  
> to
>        set up a flexible hierarchy of private addressing zones.  In
>        particular, host-rooted subnets become possible without  
> breaking
>        the e2e principle.
>
>    For information, no intellectual property right has been applied  
> for
>    by the author on any of SAM mechanisms.  The intent is to  
> facilitate
>    IPv6 deployment with new mechanisms that still enhance its  
> potential.
>
>
> 6.  Security considerations
>
>    Like any function where some parameters have to be configured, SAM
>    introduces a risk of human errors.
>
>    Besides that, no security risk introduced by SAM has so far been
>    identified.  In particular:
>
>    Provided consistency between local addresses present in  
> encapsulating
>    packets and global addresses present in encapsulated packets are
>    systematic, no more address spoofing is possible than without SAM.
>
>    Due to the stateless operation of SAM, its scalability is high.
>    Prevention against denial of service attacks should therefore  
> remain
>    easy even for very intense traffic (e.g. using load balancers in
>    front of parallel devices).
>
>
> 7.  IANA Considerations
>
>    If and when this specification is stabilized and approved, option
>    codes in DHCP, DHCPv6, and ND will have to be defined to
>
>
>
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>
>
>    automatically convey SAM parameters to branch SAMs.
>
>
> 8.  Acknowledgements
>
>    As this specification has evolved during many months, precious
>    encouragement and remarks were received from Mark Townsley.  He has
>    to be warmly thanked for it.  Concerning what SAM can bring to  
> port-
>    restricted IPv4 addresses, stimulating discussions with Dan Wing,
>    Teemu Savolainen, Gabor Bajko, Pierre Levis, Jean-Luc Grimault, and
>    Alain Villefranque, have influenced progress of the work.   
> Gratitude
>    is due to them for this.  Challenging remarks, and a few (deserved)
>    criticisms from Alain Durand have also helped to better analyze how
>    SAM will coexist with NATs.  He deserves credit for it.
>
>
> 9.  References
>
> 9.1.  Normative References
>
>    [RFC1918]  Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G.,  
> and
>               E. Lear, "Address Allocation for Private Internets",
>               BCP 5, RFC 1918, February 1996.
>
>    [RFC2131]  Droms, R., "Dynamic Host Configuration Protocol",
>               RFC 2131, March 1997.
>
>    [RFC3315]  Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
>               and M. Carney, "Dynamic Host Configuration Protocol for
>               IPv6 (DHCPv6)", RFC 3315, July 2003.
>
>    [RFC4193]  Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast
>               Addresses", RFC 4193, October 2005.
>
>    [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
>               "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
>               September 2007.
>
> 9.2.  Informative References
>
>    [6rd]      Despres, R., "IPv6 Rapid Deployment on IPv4
>               infrastructures (6rd) - Work in progress
>               (draft-despres-6rd-02)", October 2008.
>
>    [Boucadair]
>               Boucadair, M., Grimault, J-L., Levis, P., and A.
>               Villefranque, "Behaviour of BitTorrent service in an IP
>               Shared Address Environment
>
>
>
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> 2008
>
>
>               (draft-boucadair-behave-bittorrent-portrange-02 - work  
> in
>               progress)", january 2009.
>
>    [LISP]     Farinaci, D., Fuller, V., Oran, D., Meyer, D., and S.
>               Brim, "Locator/ID Separation Protocol (LISP) -
>               draft-farinacci-lisp-09", December 2008.
>
>    [RFC0959]  Postel, J. and J. Reynolds, "File Transfer Protocol",
>               STD 9, RFC 959, October 1985.
>
>    [RFC2461]  Narten, T., Nordmark, E., and W. Simpson, "Neighbor
>               Discovery for IP Version 6 (IPv6)", RFC 2461,
>               December 1998.
>
>    [RFC2663]  Srisuresh, P. and M. Holdrege, "IP Network Address
>               Translator (NAT) Terminology and Considerations",
>               RFC 2663, August 1999.
>
>    [RFC3056]  Carpenter, B. and K. Moore, "Connection of IPv6 Domains
>               via IPv4 Clouds", RFC 3056, February 2001.
>
>    [RFC3286]  Ong, L. and J. Yoakum, "An Introduction to the Stream
>               Control Transmission Protocol (SCTP)", RFC 3286, May  
> 2002.
>
>    [RFC3582]  Abley, J., Black, B., and V. Gill, "Goals for IPv6 Site-
>               Multihoming Architectures", RFC 3582, August 2003.
>
>    [RFC3704]  Baker, F. and P. Savola, "Ingress Filtering for  
> Multihomed
>               Networks", BCP 84, RFC 3704, March 2004.
>
>    [RFC4219]  Lear, E., "Things Multihoming in IPv6 (MULTI6)  
> Developers
>               Should Think About", RFC 4219, October 2005.
>
>    [RFC4301]  Kent, S. and K. Seo, "Security Architecture for the
>               Internet Protocol", RFC 4301, December 2005.
>
>    [RFC4864]  Van de Velde, G., Hain, T., Droms, R., Carpenter, B.,  
> and
>               E. Klein, "Local Network Protection for IPv6", RFC 4864,
>               May 2007.
>
>    [RFC4960]  Stewart, R., "Stream Control Transmission Protocol",
>               RFC 4960, September 2007.
>
>    [RFC5214]  Templin, F., Gleeson, T., and D. Thaler, "Intra-Site
>               Automatic Tunnel Addressing Protocol (ISATAP)", RFC  
> 5214,
>               March 2008.
>
>    [Shim6]    Nordmark, E. and M. Bagnulo, "Shim6: Level 3 Multihoming
>
>
>
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>
>
>               Shim Protocol for IPv6 - Work in progress
>               (draft-ietf-shim6-failure-detection-09)", October 2007.
>
>    [draft-carpenter-renum-needs-work-01]
>               Carpenter, B., Atkinson, R., and H. Flinck, "Renumbering
>               still needs work - Work in progress", December 2008.
>
>    [shim6 fail detec]
>               Arkko, J. and I. van Beijnum, "Failure Detection and
>               Locator Pair Exploration Protocol for IPv6 Multihoming -
>               Work in progress (draft-ietf-shim6-failure- 
> detection-09)",
>               July 2007.
>
>
> Author's Address
>
>    Remi Despres
>    3 rue du President Wilson
>    Levallois,
>    France
>
>    Email: [e-mail]
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
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>
> Full Copyright Statement
>
>    Copyright (C) The IETF Trust (2008).
>
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>    contained in BCP 78, and except as set forth therein, the authors
>    retain all their rights.
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>    "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE  
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>
>
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> Despres                    Expires May 5, 2009                 [Page  
> 26]
>
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