1 The Virtual Enterprise Model Carlos Molina-Jimenez TAPAS meeting, Dortmund th Feb 2003

2 Motivation for this presentation Why do we need to know about virtual enterprises? Where do virtual enterprises fit in TAPAS?

3 TAPAS objective To develop an architecture to host distributed applications.  applications use a wide variety of services.  services are provided by different autonomous organizations. Market place retail bank ISP credit rating agency vendor buyer vendor SSP ASP TTP retail bank independent organization SLA

4 Our problem: how to regulate the interactions and resource sharing. Market place retail bank ISP credit rating agency vendor buyer vendor SSP ASP TTP retail bank independent organization SLA

5 We’re interested in n to n interactions One to one interaction is a special case. The general case is n to n. Market place retail bank ISP credit rating agency vendor buyer vendor SSP ASP TTP retail bank independent organization SLA one to one n to n

6 The virtual enterprise (VE) model We believe that our VE model is a useful abstraction to reason about n to n business interaction. What kind of interaction?  client-server,  peer-to-peer,  any other!…our VE model makes no assumptions. In this presentation we’ll discuss the VE model

7 Outline of the presentation 1. What is a virtual enterprise? 2. Why a virtual enterprise is called virtual? 3. Location of actual objects and realisation of virtual objects. 4. Contracts and virtual enterprises: what is a contract? What does it do? 5. Conclusions and discussion.

8 What is a virtual enterprise? A VE is an enterprise composed out of n existing enterprises (E 1,E 2,…E n ) that are  independent (and want to remain independent) and  possibly mutually suspicious, but  want to establish a close business relationship contractual term (normally long term, months, years)

9 VEs composed of n>2, n=2 and n=1 enterprises n > 2 --typical of multi enterprise partnership. n = 2 --typical of service/provider relationships. n = 1 –the simplest VE we can think of. E1E1 E2E2 EnEn VE E1E1 E2E2 E1E1 n > 2n = 2n = 1 We’ll open and see inside the boxes soon!!! export resources

10 Motivation for creating a VE (ex. n = 2) E1E1 E2E2 EnEn VE E1E1 E2E2 EnEn External user of VE Service provision to internal users Service provision to external users

11 virtual? Why is a virtual enterprise virtual? in computer sc. virtual is something that is simulated by means of software.  virtual memory for example. a virtual enterprise is called virtual because it is intangible (untouchable).  its resources (objects) are simulated by software. Where are the actual objects used by a VE located?

12 Only shared objs are used for building VEs Internet E1E1 E2E2 O1O1 OnOn O1O1 OmOm private objects shared objects shared objects O1O1 OnOn O1O1 OmOm private objects Can be used for composing a virtual enterprise

13 Virtual objects are only references Internet E1E1 E2E2 O 1.E 1 O n.E 1 O1O1 OmOm private objects shared objects shared objects O1.E2 O n.E 2 O1O1 OmOm private objects VE O 1.E 1 O n.E 1 O 1.E 2 O n.E 2 virtual objects: references to actual objects

14 Location of actual and virtual objects E1E1 E2E2 EnEn VE tangible (actual) objects: PCs, printers servers, DBs, etc. intangible (virtual) objects The actual objects are located within the actual enterprises. The virtual objects are located no-where, they don’t exist. The virtual objects are visible within the VE. They are references to actual objects within E 1,…E n What if E 1,…E n are not actual but virtual?

15 Location of actual objects E1E1 E2E2 EnEn VE 1 tangible (actual) objects: PCs, printers servers, DBs, etc. intangible (virtual) objects E1E1 E2E2 EnEn VE 2 E1E1 E2E2 EnEn VE n VE 1_2 VE

16 Two approaches for building an ASP Market place ISP SSP ASP SLA Special case ASP is a virtual enterprise! Market place SLA ASP ISP SSP ASP 1 SLA ISP SSP ASP n SLA ISP SSP ASP 2 SLA SLAs between ASP 1, …, ASP 2 Export objects ASP is a distributed system! General case

17 A virtual ASP hosting an auction SLA ASP 1 SLA SSP ISP ASP 2 SLA SSP ISP ASP 3 SLA SSP ISP object 1 object n object 1 object n object 1 object n Virtual ASP (hosting and AUCTION) bidder export object actual location Africa America Europe SLAs between ASP 1, ASP 2, ASP 3

18 Contracts and virtual objects Internet E1E1 E2E2 O 1.E 1 O n.E 1 O1O1 OmOm private objects shared objects shared objects O 1.E 2 O n.E 2 O1O1 OmOm private objects O 1.E 1 O n.E 1 O 1.E 2 O n.E 2 virtual objects: references to actual objects policies for accessing actual objects + VE --a contract

19 Conclusions The virtual enterprise model makes the concept of ASP recursive. This is crucial for Internet applications because  Concept, models, applications, etc. that are not recursive do not scale well in the Internet.

20 References Contract Representation for Run-time Monitoring and Enforcement. Carlos Molina- Jimenez, et. al. Draft, Uni. of Newcastle, Dec 2002.