Dear All, The word Grid means different things to different people and this quite frequently leads to misunderstandings and conflict. This is especially true within OGF where people from many different domains and backgrounds discuss "Grids". While each and every definition themselves are as valid as each other, trying to discuss a concept from two possibly unrelated perspectives is quite difficult. Before we move forward in the PGI activity we therefore need understand what we mean by "Grid" and hence the problem we are trying to solve. It seems that in some recent threads the word "production" has cause some disagreements as this word is more commonly used to reflect quality rather than concepts. From my perspective I can try to define the core properties that I see are key when describing the EGEE infrastructure. I would hope that similar infrastructures with whom EGEE would like to interoperate would have a similar description. I would like to introduce the term "Muti-institutional infrastructures for e-Science" which can be used to describe something with the following properties. 1) Multi-institutional. The EGEE infrastructure is composed by linking resources that reside at autonomous academic institutes. The key concept here is the administrative domain which maps to a real institute and that there is more than one institute in the infrastructure. 2) The Virtual Organization The main aspects that links these institutes is the drive to collaborate in order to do science. The collaborations are defined by Virtual Organizations. 3) x509 Certificates and Proxies Users are identified by x509 certificates which are provided by CAs accredited by the IGTF. Proxies are typically used to interact with services. 4) VOMS To identify which VO a user is belong to is by contacting VOMS. VOMS also supports Roles an Groups within the VO which is implemented by adding attributes to the proxy. 5) Multiple Services The are many different types of services each of which can define their own interfaces which may or many not be a Web Service. 6) Parrallel Information System The information about services is found by querying an information system which is not necessarily related to the service interface. 6) Scale 100s of administrative domains, thousands of users, thousands of services, millions of computing actives and petabytes of data. This may be a can of worms but if we can agree on a set of properties for what we mean by "Production Grid" it might help in the discussions. I don't mean that anything that has different properties is not a production grid, I just want to clarify what this group mean when it talks about a Grid infrastructures. Laurence Laurence