Re: Issue 36: Handling UNACCEPTABLE_PATH

Tero Kivinen wrote:

>There is a problem in case the UNACCEPTABLE_PATH is not for address in
>the IP header but some other address pair. I mean the initiator sends
>packet with IPA1, IPB1 N(CHANGE_PATH). That reaches the responder, but
>he decides to send N(UNACCEPTABLE_PATH) back. The reply never reaches
>the initiator because of uni-directional connection or something. The
>initiator retransmits the packet with IPA2, IPB2 N(CHANGE_PATH). This
>would be ok for the responder, but as he has already generated the
>reply N(UNACCEPTABLE_PATH) he will retransmit that back. This will
>reach the initiator and he will be receiving wrong information which
>path was unacceptable.
>  
>
Agreed.

>Fixing this is quite simply, we add the address pair that was
>unacceptable to the notify data. In case there is NAT in the path the
>responder might not recognize all the addresses, but in case of no
>NATs it immediately knows which address pair wasn't acceptable. 
>  
>
Hmm. Maybe it would then be better to introduce a counter
or message id to N(CHANGE_PATH) and N(UNACCEPTABLE_PATH)
rather than the addresses, which can change en-route?

--Jari