It is possible that data can be transferred to the third car. In this case, the user arranges the control channel with two servers and organizuetpryamoy data channel between them. Management team are by the user, and data directly between the servers (Figure 4.3). The control channel should be opened when transferring data between machines. In the case of the closure of data transfer is terminated.
Fig. 4.3. Connection with two different servers and data transfer between them. Modes of communication in the protocol a lot of attention paid to different ways of exchanging data between machines of different architectures. Indeed, what is there not on the Internet, from pc and Macs to supercomputers. They all have different word length and many different order of bits in a word. In addition, various faylovyesistemy work with different data organization, which is expressed in the concept of an access method.
In general, case, in terms of ftp, the exchange can be threaded, or block, encoded in an intermediate format or without text or binary. Pritekstovom exchange of all data is converted to ascii and in this form are transmitted over the network. Exception constitute only the data ibm mainframe, which at in ebcdic, if both interacting machines ibm. Binary data is transmitted sequence of bits, or are during the session management. Usually, when streaming data is transferred in one session one data file, while block method for can send multiple files. Having described in general terms, the communication protocol, you can go to the description of means of sharing via ftp.