Re: [Hipsec] HIP transforms

[Ari Keranen <[e-mail]>]

Hi,

On Feb 12, 2011, at 6:47 PM, Tobias Heer wrote:
[...]
> I see two options here:
> 
> 
> A) Give all transforms the same type number and an additional sub-type number.
> The order of the parameters in the HIP packet would indicate the preference
> then. From a handling-point-of-view this option is very similar to as it is now
> but there would be just one transform type with subtypes.
> 
> Example HIP packet excerpt:
> (2096 is an arbitrary type number for the new transport form parameter)
> +------+ +------+--------+ +------+--------+ 
> |Header| | 2096 | 1| ESP | | 2096 | 2| XYZ | ... 
> +------+ +---------------+ +------+--------+
> This would mean ESP is preferred, XYZ is not preferred but supported.
> 
> 
> 
> B) Give all transforms different type numbers, keep the ordering and express
> preference in a list. From a specification-point-of-view this is similar to what we have now.
> 5202 could stay mostly as it is now.
> 
> Example HIP packet excerpt:
> (ESP has type number 4095 but for the clarity of the example I use 2095)
> +------+ +----+--------------+ +----+---+ +----+---+ 
> |Header| |2050|List: ESP, XYZ| |2095|XYZ| |4095|ESP| ... 
> +------+ +----+--------------+ +----+---+ +----+---+
>                ^
>                |
> List------------+
> 
> Again, this would mean ESP is preferred, XYZ is not preferred but supported.
> 
> I prefer option B because it is more similar to other negotiations in BEX.
> 
> Any opinions?

I'd go for B.


Cheers,
Ari