Hello calderara,

c> 1 - What is the way to communicate between layers ?

Depends on your environment and physical tier locations.
If everything is on the single machine then use IPC ways, like pipes, else
consider using web-services.
I'd recommed to implement services with WCF, which allows you easily to change
the communication protocol.

c> 2- How those different layers are physically represented as files :
c> Does each layer = 1 assembly with organised classes ?

doen't matter

c> Does each layers is a set of assenbly within a same name space
c> identifyuing
c> the layer they belongs too ?

Yep. only don't forget to follow the namespace guidelines

c> 3 - Does  a service layer is organised in one assembly per service ?

so, the question is either to have monolithic or component architecture -
use the single dll if your services aren't gonna be extended by plugins.

c> 4 - How to provide new services to be used by my aplication without
c> recompiling

you need to couple your service interaction tight. Services should be autonomous
and discovered. It means you need to add tight reference to other services.
All services should be references and plugged via config files. And idealy
be discovered smth like via UDDI.

---
WBR,  Michael  Nemtsev [.NET/C# MVP].  
My blog: http://spaces.live.com/laflour
Team blog: http://devkids.blogspot.com/

"The greatest danger for most of us is not that our aim is too high and we
miss it, but that it is too low and we reach it" (c) Michelangelo

c> Dear all,
c>
c> Im ma building an event system application in a kind of service based
c> application. Events system means collecting machine alarms, archive
c> them in a database, provide them to a user interface and provide some
c> statistical calculation frequency.
c>
c> Based on those requirement I am loosing my mind on the way to
c> organise my architecture in order to be in a good style an approach.
c>
c> UI layer:
c> Frist of all of course there is the UI layer in charge to request
c> different
c> ype of Services from the service layer
c> Service Layer:
c> Provide to users, Archiving Service, Collecting service, statistical
c> service, publishing service
c> Data layer:
c> In charge of storeing and retriving data from database.
c> Based on those different layer I have difficulties to answer follwing
c> questions,hoping I will get help from you :
c>
c> 1 - What is the way to communicate between layers ?
c> 2- How those different layers are physically represented as files :
c> Does each layer = 1 assembly with organised classes ?
c> Does each layers is a set of assenbly within a same name space
c> identifyuing
c> the layer they belongs too ?
c> 3 - Does  a service layer is organised in one assembly per service ?
c> 4 - How to provide new services to be used by my aplication without
c> recompiling
c>
c> I know it might be hard to answer but if you could guide me how to
c> organised my classes in order to be in a good architeture I will
c> appreciate
c>
c> regards
c> serge