Re: error messages and silently discarding packets

[Brian E Carpenter <brc@zurich.ibm.com>]

...
> The question is whether we should use ICMP error message or if we should 
> define a shim6 error message within the shim6 protocol
>
> Iljitsch suggested we do define such an error message, while the current 
> spec uses ICMP error messages, what should we do?

In my opinion it depends whether the error messages are *necessary*
or whether they are only advisory.

If they are *necessary* for shim6 to function, that means they need
to arrive whatever ICMP filters are in place. So they would need to
be shim6 messages. If they aren't functionally necessary, ICMP
seems OK.

> Second, about silently discarding packets:
>
> there are quite a few situations that the shim6 protocol silently 
> discard packets that it considers an error or are not supported.

If the error messages are not functionally necessary, I suggest silent
discard as a SHOULD in all cases, with implementers allowed to implement
error messages as a configurable debug option.

    Brian