Re: soft state (was Re: shim6 and bit errors in data packet headers

[Iljitsch van Beijnum <iljitsch@muada.com>]

On 17-mei-2005, at 20:15, marcelo bagnulo braun wrote:

> > I think we can use the same host mechanism which avoids NUD probes  
> > to avoid reachability tests (this mechanism is a positive advise  
> > "everything is fine" from the transport layer to the IP layer).
> > For transports like TCP that is sufficient.

> well, i guess that my perception is that ULP feedback is not so  
> common, and that it will be common to fall back in reachability  
> test to verify that the path is working...
> Does current TCP usually implement this positive feedback for  
> avoiding NUD?

I can't be sure but I don't think host operating systems such as the  
KAME/BSD family and Linux currently implement NUD.

Also note that the feedback doesn't always have to be from the actual  
transport protocol: just observing packets flowing in both directions  
will tell you that all is well. This should be easy to implement in  
the shim.