Dear Jean-Pierre,
see my comments below !
GARBISU Jean-Pierre FTRD/DMI/CAE wrote:
>
> Hi
> About the "Network Services", even if it doesn't (perhaps) fit exactly what
> S. Salsano have in mind, I would like to add the following :
> IMHO these network services are essential.
> I can't see how any kind of customers'e2e SLSs could be individually
> processed in the backbones supporting QoS services.
>
> To give an example, VoIP. One could imagine that all customers of an ISP
> don't ask for exactly the same SLS's metrics e.g some customers ask for 100
> ms OWD between their CPEs, others ask for 80 ms, other for 120 etc (based on
> different gateways needs, different access lines speeds etc.). The ISP could
> decide to implement only one VoIP network service wrt the OWD metric (e.g.
> 50 ms) between its PoPs instead of implementing (within all its backbone QoS
> toolbox : TC, TE, etc.) 3 VoIP OWD metrics. The "generic" network service in
> the core permits to handle varied specific e2e SLS.
>
> Another example could be ERP applications (e.g. transactional business
> critical applications). All customers don't share the same ERP apps but
> generally one could imagine that customers could ask for a prioritized e2e
> QoS service for them (e.g. somewhere between real time needs and best effort
> needs; OWD varying between a few hundred ms and a few secondes). The ISP
> could decide to implement one or two generic ERP network services which
> should cover the needs of a large variety of customers applications instead
> of trying to implement specific PoP to PoP service per ERP type.
>
> Finally it seems well established that the closer you get from the core
> networks, the fewer CoS (if ever) and dynamicity you should consider,
> compared to greater variety of CoS and dynamicity you can try to implement
> at the access.
> That's why mapping of (possibly numerous) e2e SLS on (few) PoP to PoP
> network services seems very attractive.
>
> Best regards.
>
> jeanpierre.garbisu@francetelecom.fr
>
I agree with your opionion... in the core you'll have definitely
few CoS or few "(Core) Network services".
Note that I do not think that you should exactly reflect
this set of (Core) Network Service in a set of Network
Service in the access SLS.
You have "customers'e2e SLSs" at the access, and then you have
to map into your "(Core) network services".
This mapping process can be complicated if the SLS contains a lot
of parameters, and the user can freely select any combination
of values for these parameters. The mapping process can be
simplified if a set of "predefined SLS patterns" is defined.
I think the right approach should be to define the semantic
content of the SLS in a very complete way, with the needed
set of parameters and options... which will end in a complex SLS.
Then the use of predefined SLS patterns is an (optional)
way to simplify the operation.
Best 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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