Re: Sending ICMP error upon receiving an NA without SLLAO in 2461bis

> The basic issue left is whether we should allow a node to send an ICMP error
> due to the reception of an NA without the SLLAO. The reason for sending the 
> ICMP error is to inform upper layers that the communication has
> failed.

It took me a while to figure out what you are proposing. To summarize:
in the case where where a node receives an NA without an SLLAO, but it
is expecting an SLLAO (so it can complete the Neighbor Cache Entry),
such a received NA is "an error". In the case where a regular data
packet is queued pending completion of the NCE, you'd like to be able
to send back an ICMP error indicating "dest unreachable". Right?

This seems like a fairly minor optimization and one that deals with a
a potential "implementation error" (since I understand this situation
would normally only arise of the sender of the NA incorrectly left off
the SLLAO).  If this is the case, IMO, it's not worth modifying the
spec to allow this. Indeed, I'd have to think a bit to convince myself
that it couldn't lead to potential cases where an ICMP error would be
(incorrectly) sent when simply ignoring the faulty NA is actually the
more correct response (i.e., if proxies are present and more than one
NA is generated).

Is this a situation that has come up in actual testing/usage?

Thomas

--------------------------------------------------------------------
IETF IPv6 working group mailing list
ipv6@ietf.org
Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6
--------------------------------------------------------------------