[rohc] RE: ROHCv2 Implementation msn, sn and ipid in co_common/co_repair.

["Kristofer Sandlund" <kristofer.sandlund at ericsson.com>]

Hi,

I think the changes you propose look fine to me, so I will add these
to the next revision of the draft.

/Kristofer

Carl Knutsson <mailto:carl.knutsson at effnet.com> wrote on den 21
september 2007 11:34 :

> Hi Kristofer and Ghyslain,
> 
> I have some suggestions for the compressed formats co_common
> and co_repair for all
> profiles. I would like to have fields that differ between
> profiles last in the
> packet formats as much as possible, because of implementation
> reasons. I would also like to see depending field located after the
> field they 
> depend on the
> compressed formats as much as possible.
> 
> I suggest that ipid field is moved after the 'msn' field in
> co_common and
> co_repair for all profiles. ('s/msn/sequencenumber/' for esp
> profile). ipid is in many cases dependent of the msn.
> 
> I would also like to see a two changes in the encoding method
> of the sequence
> number in the ESP profile:
> 
> First, I would like the 'sequencenumber' field to be encoded using the
> REORDER_RATIO in co_common. The reson for this is to make
> packet selection easier
> and make the calculation of p the same for all k.
> 
> My second suggestion concerning the ESP sequence number is to
> remove the last 32
> bit option in the sdvl-encoding(co_common). 32 bit can be
> sent co_repair (with
> fewer bytes) and there is no need for redundancy here:)
> 
> This would mean a new encoding function.
> 
> To help for you guys out.. here is the FN (that is if the
> working group agrees to
> my changes).
> 
> svdl_esp_sn {
>   UNCOMPRESSED {
>     sn [ field_width ];
>   }
> 
>   COMPRESSED lsb7 {
>     discriminator =:= '0'               [ 1 ];
>     sn =:= msn_lsb(7)                   [ 7 ];
>   }
> 
>   COMPRESSED lsb14 {
>     discriminator =:= '10'              [  2 ];
>     sn =:= msn_lsb(14)                  [ 14 ];
>   }
> 
>   COMPRESSED lsb21 {
>     discriminator =:= '110'             [  3 ];
>     sn=:= msn_lsb(21)                   [ 21 ];
>   }
> 
>   COMPRESSED lsb29 {
>     discriminator =:= '111'             [  3 ];
>     sn =:= msn_lsb(29)                  [ 29 ];
>   }
> }
> 
> /Calle

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