Carlos Alberto Kamienski wrote:
>
> > What is interesting is that we found the need to have pre-defined
> > SLSs (we called it "Network Services" but the name can be misleading):
> > for ease of negotiation and implementation only a subset
> > of parameters can be specified, while the others are given by default
> > with reference to a small set of "well known services".
> > This is in perfect agreement with your idea that a well-known service
> > identifer is just a compression of the SLS for ease of negotiation.
>
> Well-known services do negotiation easier, but I don't think they would
> be just a compression of the SLS. I do not think an SLS will be always
> sufficient.
>
> A quantitative well-known services would be a mix of:
>
> - explanation in a human language (eg, English)
> - mathematics
> - definition of parameters and possibly limit values for them
>
> My point is that one domain may not be able to figure out
> services that other domains are willing to negociate just by observing
> parameters in the SLS. I cannot give many examples, but the Virtual
> Wire (VW) PDB is a good one! How could one domain know that one SLS
> refers to VW and not to other different service (maybe not so
> strict) using EF PHB ?
Dear Carlos,
I understand your concerns... I admit I have not the definitive answers
for everything, but may be what you have described for a quantitative
well known service may be expressed in terms of an SLS...
Referring to your example, I see that the VW PDB could be expressed
in an SLS with QoS parameters like:
Absolute maximum delay: 100 ms
Packet loss: 0 %
A different service based on the EF PHB could have this parameters
in the SLS (a quantitative one):
99.9 delay percentile: 100ms
Packet loss < 10^-6
And a even different qualitative service based on EF could have:
Delay: low
Packet loss: very low
(If an SLS also allows qualitative values :-)
By the way, the user of the SLS could even be not interested in
knowing what diffserv PHB is used in the diffserv network...
Regards,
Stefano
--
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Stefano Salsano
CoRiTeL - Consorzio di Ricerca sulle Telecomunicazioni
E-mail : salsano@coritel.it URL : http://www.coritel.it
Tel. : +39 06 20410029 Address : Via di Tor Vergata, 135
Fax. : +39 06 20410037 00133 Roma - ITALY
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