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

["Wes Beebee (wbeebee)" <[e-mail]>]

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: [e-mail] [mailto:[e-mail]] On Behalf Of
Wojciech Dec (wdec)
Sent: Thursday, June 26, 2008 10:05 AM
To: Brian Haberman; [e-mail]
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: [e-mail] [mailto:[e-mail]] On Behalf 
> Of Brian Haberman
> Sent: 26 June 2008 14:17
> To: [e-mail]
> 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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