Re: ND (NUD) on ISATAP links

Karen E Nielsen (TED) wrote:
Karen

Consider a behavior of an ISATAP host that connects to multiple
ISATAP router and is attempting to establish a connection
to an IPv6 native address.

I can see NUD being performed to the ISATAP router and
if NUD proves the router unreachable (IPv6 address of
the router is not reachable), another router may be tried.

This is the case where I see NUD being usefull in the ISATAP
environment.  You are right that it is not very usefull between
2 ISATAP hosts.

-vlad

> 
> 
> Well, actually my question(s) is:
> 
> 1. Do we want "real" IPv6 NUD on ISATAP links ? - Or
> 2. Do we want *only* the NUD functionality achieved by virtue of 
>    the mechanisms provided by the IPv4 layer ?
> 3. Is it sound to require NUD to be performed on ISATAP links.
> 
> If the answer to 1. is Yes, then a mechanism need to be defined.
> This does not necessarily need to involve changing NUD from 2462, it could simply be fixed
> by doing NS/NA exchange on top of static address resolution in ISATAP (or something else), i.e.
> one would define an "ISATAP IPv6 address resolution mechanism" or if you like
> an "IPv6 over NMBA address resolution mechanism" and then use this combined with RFC 2461.
> Strictly speaking this doesn't mean adding a new state to the resolution/NUD mechanism, you're
> simply replacing standard (multicast) IPv6 address resolution with something else.
> 
> If the answer to 2. is Yes. Then ISATAP tunnels should wrt ND behave as general
> automatic tunnel mechanism, RFC 2893, i.e. NC and NUD need not be maintained since
> it has no effect.
> 
> Wrt. 3 This might be sound for hosts, but is doesn't seem to scale for routers on large links.
> 
> 
> Karen
> 
> 


-- 
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Vladislav Yasevich		Tru64 UNIX - IPv6 Project Lead
Hewlett Packard 		Tel: (603) 884-1079
Nashua, NH 03062		ZKO3-3/T07