Applications

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Applications

FTP

Given a reliable end-to-end trasport protocol like TCP, File Transfer might seem trivial. But, the details authorization, representation among heterogeneous machines make the protocol complex.
FTP offers many facilities :

• Interactive Access : Most implementations provide an interactive interface that allows humans to easily interact with remote servers.
• Format (representation) specification : FTP allows the client to specify the type and format of stored data.
• Authentication Control : FTP requires client to authorize themselves by sending a login name and password to the server before requesting file transfers.

FTP Process Model FTP allows concurrent accesses by nultiple clients. Clients use TCP to connect to the server. A master server awaits connections and creates a slave process to handleeach connection. Unlike most servers, the slave process does not perform all the necessary computation. Instead the slave accepts and handles the control connection from the client, but uses an additinal process to handle a separate data transfer connection. The control connection carries the command that tells the server which file to transfer.