Re: [Ila] Proposed charter

[Tom Herbert <[e-mail]>]

> I would suggest the use of the term "transform" to describe what is
> happening, rather than "translate".
>
>
> In English usage, I think "transform" is describing a perfect change from
> one form to another. "Translate" is a word that that I think has a less than
> perfect change from one form to another meaning. We translate between spoken
> languages, because the change isn't perfect.
>
> The process ILA performs is a perfect transform, once at ingress to the ILA
> domain, into the ILA domain's address space, and a perfect transformation
> back at ILA egress. If the transformation isn't perfect, then a fault has
> occurred.
>
> The other reason I'd avoid "translate" is that it in the IETF it carries
> with it the association with IPv4 NAT and its drawbacks. ILA doesn't suffer
> from these issues because of the full reversal of the address changes upon
> egress from the ILA domain.
>
> (So how come I don't like NAT at all, yet am ok with what ILA is doing? The
> full reversal of the address charges at ILA egress is the first reason.
> Secondly, within the ILA domain, the ingress ILA device is a host, that is
> in effect originating the packet within the ILA domain it is sending to the
> egress ILA device, which is also a host or end-point within the ILA domain.
>
> The ILA domain is effectively a virtual link layer or an underlay network
> for the traffic being carried between hosts outside of the ILA domain. As
> long as the ILA domain is perfectly transparent to the overlay network and
> its hosts, then what ever happens within the ILA domain doesn't matter,
> similar to how link layer compression, as long as fully and perfectly
> reversed, also doesn't matter.)
>
Mark, thanks for the great explanation! I completely agree that
"transform" is better terminology. We definitely want to distinguish
ILA from NAT, and an in fact I think your explanation is probably a
good basis for the "Why ILA is not NAT" section in the architecture
doc.

Tom