Re: ds2exp; a possible mapping [was Re: [mpls-linux-general] Re: MPLS-Diffserv Instructions + Counters]

[<pim...@in...>]

Stefano Avallone wrote:
> 
> Hi all
> 
> > > ds2exp:0x38:0xa:1:0x12:2:0x1a:3:0x22:4:0x2e:5
> > >
> > > This maps:
> > > AF1x -> 1
> > > AF2x -> 2
> > > AF3x -> 3
> > > AF4x -> 4
> > > EF -> 5
> 
> based on my understanding of draft-ietf-mpls-diff-ext-09.txt, I have some doubts about the utility of the above mapping, unless we want to disregard the drop probability (the above 'x').
> According to me, if we want to set up an E-LSP we must encode the full DSCP into the EXP bits (otherwise we lose the drop probability); if we want to set up an L-LSP (which carries packets of a given PSC, e.g. AF1 or AF2) in the EXP bits we should encode just the drop probability.
> 
> Please correct me if I'm wrong
No you are correct. If you want to support the drop probability you must
encapsulate the complete DSCP in the EXP and restrict yourself to 2 AF
classes. AF(12)(123)+BE+EF -> 8 EXP values.

Pim.
> Regards,
> Stefano
> 
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-- 
Pim Van Heuven            Ghent University - IMEC
Department  of  Information  Technology   (INTEC)
Sint-Pietersnieuwstraat, 41 B-9000, Gent, Belgium
pim...@in...
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