Re: [Softwires] IPv4 Residual Deployment - Unified-standard proposal 4rd

[Rémi Després <[e-mail]>]

2012-03-12 03:08, Maoke:
> 2012/3/9 Rémi Després <[e-mail]>
...
> If a source sends to a shared IPv4 address with a port-less protocol, it will receive a  "destination unreachable" ICMPv4 packet.
> Its code will be either "network unreachable", because no CE had the derived IPv6 address (sec. 4.7), or "protocol unreachable", because the reached CE NAT44 cannot process this port-less protocol.
> The usual error-signalling mechanism works as it has to.
>  
>  
> ok. now i got the whole picture. sorry for the late understanding.
> but does this means 4rd-U is an extension of NAT44 or at least depends upon NAT44?
>  
> RFC6145 has no such dependence at all.


R-1 says:
"A node whose CE is assigned a shared IPv4 address MUST include a NAT44 [RFC1631].  This NAT44 MUST only use external ports that are in the CE assigned port set."
For other cases, the choice remains open. In CEs that are assigned IPv4 prefixes, NAT44s are clearly possible but not required. 

In a CE-node that is only a host, the NAT44 might be optional. Would it be good or not to permit it isn't clear to me but, in R-1, a SHOULD seems more appropriate than a MUST.
Thanks for the point.

RD