RE: 6MAN WG Last Call:draft-ietf-6man-ipv6-subnet-model-00.txt

["Wojciech Dec (wdec)" <wdec at cisco.com>]

I understand that the topic has a fair bit of history, but could someone
please re-explain the use-case that justifies keeping such
cross-subnet-but-hey-no-router behaviour? 
Personally I see little value in it in today's world of home routers,
but plenty of potential for confusion for users if not downright
additional security issues for operators.

-Woj.


> -----Original Message-----
> From: Wes Beebee (wbeebee) 
> Sent: 26 June 2008 16:29
> To: Wojciech Dec (wdec); Brian Haberman; ipv6 at ietf.org
> Cc: MILES DAVID; Bob Hinden
> Subject: RE: 6MAN WG Last 
> Call:draft-ietf-6man-ipv6-subnet-model-00.txt
> 
> This rule derives directly from the Terminology section of 
> RFC 4861 (definition of on-link).
> 
> Note that the presence of a bogus entry causes no harm (the 
> routing table takes precedence over the ND cache in this case).
> 
> However, the removal of the rule DOES cause harm in the case 
> of communication without routers.
> 
> Therefore, we currently see no reason to change the text.
> 
> - Wes & Hemant
> 
> -----Original Message-----
> From: ipv6-bounces at ietf.org [mailto:ipv6-bounces at ietf.org] On 
> Behalf Of Wojciech Dec (wdec)
> Sent: Thursday, June 26, 2008 10:05 AM
> To: Brian Haberman; ipv6 at ietf.org
> Cc: MILES DAVID; Bob Hinden
> Subject: RE: 6MAN WG Last 
> Call:draft-ietf-6man-ipv6-subnet-model-00.txt
> 
> Based on a recent thread
> (http://www.ops.ietf.org/lists/v6ops/v6ops.2008/msg00896.html)
>  the following paragraph from the draft appears to warrant 
> some more thought if not outright a revision
> 
> "   In addition to the Prefix List, individual addresses are 
> on-link if
>    they are the target of a Redirect Message indicating 
> on-link, or the
>    source of a valid Neighbor Solicitation or Neighbor Advertisement
>    message.  Note that Redirect Messages can also indicate an 
> address is
>    off-link.  Individual address entries can be expired by 
> the Neighbor
>    Unreachability Detection mechanism."
> 
> Using unconditionally the source address of a neighbour 
> solicitation or NA to determine on-link would indeed appear 
> to be undesirable, unless the intent is allow some direct 
> host-host cross subnet/prefix communication without a router 
> involved at any stage (this is not a good idea IMO). A 
> constraint could be introduced such as: A host only learns 
> on-link addresses from the source of NS and NA messages iff 
> it already has an on-link prefix that would cover that 
> address. Learning from Redirect messages would continue to be allowed.
> 
> My 2c.
> -Woj.
>  
> 
> > -----Original Message-----
> > From: ipv6-bounces at ietf.org [mailto:ipv6-bounces at ietf.org] 
> On Behalf 
> > Of Brian Haberman
> > Sent: 26 June 2008 14:17
> > To: ipv6 at ietf.org
> > Cc: Bob Hinden
> > Subject: 6MAN WG Last Call:draft-ietf-6man-ipv6-subnet-model-00.txt
> > 
> > All,
> >       This message starts a 3-week 6MAN Working Group Last Call on
> > advancing:
> > 
> >       Title     : IPv6 Subnet Model: the Relationship between
> >                   Links and Subnet Prefixes
> >       Author(s) : H. Singh, et al.
> >       Filename  : draft-ietf-6man-ipv6-subnet-model-00.txt
> >       Pages     : 8
> >       Date      : 2008-05-08
> > 
> > as a Proposed Standard.  Substantive comments and statements of 
> > support for advancing this document should be directed to 
> the mailing 
> > list.
> > Editorial suggestions can be sent to the document editor.  
> > This last call will end on July 10, 2008.
> > 
> > Regards,
> > Brian & Bob
> > 6MAN co-chairs
> > --------------------------------------------------------------------
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> > ipv6 at ietf.org
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