Using NS3000/iX Network Services (36920-90008)

68 Chapter 5
Network File Transfer
Three-Node Model
Three-Node Model
NFT transfers files according to the model shown in Figure 5-1. 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.