Re: [Softwires] draft-operators-softwire-stateless-4v6-motivation

[Nejc Škoberne <[e-mail]>]

Dear Med,

> [NS: If we consider a "stateful A+P" solution, we don't necessarily
> have a dependency between an IPv6 prefix and IPv4 address. Also, we
> don't have any user-session state in the Service Provider's network.
> 
> Med: Fully agree. FWIW, this is what we called "Binding Table A+P Mode" in http://tools.ietf.org/html/draft-ymbk-aplusp-10#section-4.4.

This is exactly what I had in mind.

> We do, however, have some user state (in order to do stateful tunneling,
> for example). Maybe this is included in "user-session" in your
> terminology, but then I think it would be appropriate to define the
> term "user-session" clearly.]
> 
> Med: We assumed the definition of state as mentioned in RFC1958; but I agree the terminology should be much more clearer.

Yes, "state" is implicitly defined there, however "user-session" is not
defined anywhere.

> [NS: I don't think this is true only for stateless
> solutions. If we have a stateful solution with static port allocation
> (as you mention in section 3.1.3), then implementing such an implicit
> host identification which uses also port information, is doable as
> well.]
> 
> Med: I Agree. But then you loose other benefits of the stateful: have an aggressive address sharing ratio.

You indeed loose agressive sharnig ratio, but you have somewhat more
flexible addressing. Also, the CPEs can be then really simple devices,
excluding any of the NAPT functionality, doing only stateless encapsulation.
However, what you loose/gain is irrelevant for my point. I think this
section should be modified in a way like the logging section or any
other appropriate way, which explains, that this is not the benefit of
the stateless nature, but rather the benefit of the static port allocation.

Thanks,
Nejc