2.5.1 Actors

The actors that participate in the Content Caching and Retrieval protocols are:

User: The user is the principal that requires file access to read files on another computer. The user is referred to by using the qualifiers "SMB2.1", "HTTP", or "BITS" when it is necessary to distinguish user instances. The user is external to the File Services and Content Caching and Retrieval protocols and interacts through the application. The Content Caching and Retrieval protocols only apply to the reading of existing files.

Administrator: The administrator is the person who administers the content server and hosted cache server. The administrator is interested in organizing content, setting access rights, and enabling content caching. The administrator is external to the Content Caching and Retrieval protocols and interacts with them through the Administrator Tool.

Administrator Tool: The Administrator Tool is a program that offers management functionality to the administrator by means of the Admin Client. Typical administrator tools are command-line tools and graphical shells, management utilities, and graphical management programs. The Administrator Tool is external to the Content Caching and Retrieval protocols and makes use of the Admin Client to accomplish its work.

Application: The application is a program that consumes file-reading services by means of the content client. Applications (where caching applies) have to open, read, and close files. The application is external to the File Services and Content Caching and Retrieval protocols. The application interacts with them through the content client.

Content client: The content client implements client-side protocol components and consumes the File Services that are offered by the content server. The content client can be referred to by using the qualifier "SMB2.1", "HTTP", or "BITS" when it is necessary to distinguish client instances. The content client is internal to the Content Caching and Retrieval protocols. A content client can additionally act as a distributed cache peer.

Content server: The content server's interest is to provide and maintain a secure and consistent File Access Service, as described in [MS-FASOD], and to provide content metadata as part of Content Caching and Retrieval.

Hosted cache server: The hosted cache server's interest is to cache content and to receive metadata about the availability of content segments and blocks, and then, as required, to download the segments and blocks from clients that have the relevant data. Later, when another client requests the content through a secure mechanism, the content can be retrieved from the hosted cache rather than from a content server.

Distributed cache peer: A distributed cache peer's interest is to cache and distribute data and respond to queries about the availability of data segments and blocks. Then, when a client requests the content through a secure mechanism, the content can be obtained from the distributed cache rather than from a content server.

Object Store: The File Access Services and therefore Content Caching and Retrieval are dependent on an external Object Store for storing files and directories.<7>

Wire-visible behavior of File Access Services protocols is not specified by the protocols themselves and depends on Object Store behavior.