Thay vì liệt kê từng thiết lập các thuộc tính, một tham chiếu từ xa có thể được sử dụng để đặt tên một bộ sưu tập của các thuộc tính như mặc định nền tảng phần cứng. Điều này có lợi thế là cho phép lấy riêng biệt và bộ nhớ đệm của các tập con chức năng. | CC PP - USER SIDE FRAMEWORK FOR CONTENT NEGOTIATION 121 Instead of enumerating each set of attributes a remote reference can be used to name a collection of attributes such as the hardware platform defaults. This has the advantage of enabling the separate fetching and caching of functional subsets. This might be very good if the link between the gateway or the proxy and the client agent was slow and the link between the gateway or proxy and the site named by the remote reference was fast - a typical case when the user agent is a smart phone. Another advantage is the simplification of the development of different vocabularies for hardware vendors and software vendors. It is important to be able to add to and modify attributes associated with the current CC PP. We need to be able to modify the value of certain attributes such as turning sound on and off and we need to make persistent changes to reflect things like a memory upgrade. We need to be able to override the default profile provided by the vendor. When used in the context of a Web-browsing application a CC PP should be associated with a notion of a current session rather than a user or a node. HTTP and WSP the WAP session protocol both define different session semantics. The client server gateways and proxies may already have their own well-defined notions of what constitutes a connection or a session. The protocol strategy is to send as little information as possible and if anyone is missing something they have to ask for it. If there is good reason to believe that someone is going to ask for a profile the client can elect to send the most efficient form of the profile that makes sense. We consider the following possible interaction between a server and a client. When the client begins a session it sends a minimal profile using as much indirection as possible. If the server gateway proxy does not have a CC PP for this session then it asks for one. When a profile is sent the client tries a minimal form that .
