Three-Node Model

NFT transfers files according to the model shown in Figure 5-1 “Three-Node Model”. There are three logical participants in the file transfer activity: initiator, producer, and consumer. This model is called the three-node model. According to the three-node model, the initiator, located on the system where the transfer originated, receives the request and initiates the transfer. The producer, located on the same node as the source file, accesses that file and "produces" the data that is to be transferred. The consumer, residing on the same node as the target file, "consumes" the data and writes it into the target file. All three participants are logically distinct. All three participants can be on separate nodes; the transfer request does not have to originate from either the source or the target node. It is also possible for any two or all three participants to reside on the same node.

Figure 5-1 Three-Node Model

This method, coupled with the ability to include a logon command string as part of the DSCOPY command, provides considerable flexibility. Because the initiation of the transfer request is independent of the producing and consuming functions, you don't have to explicitly log on to a remote source or target node. If you supply an appropriate logon sequence in the transfer request or in a prior DSLINE command, NFT will create a session on a remote source or target node if one does not exist already. If all the systems involved (as many as three) can establish NS-level connections with each other, you can transfer a file between any two of these nodes, and you can initiate the transfer from any of them.