A system and method is provided for communicating data and control
information between two systems, each system including a communication
protocol stack, such as an advanced program to program communication
(APPC) protocol stack which includes an I/O interface layer with modules
for OPEN, GET, PUT, UPDATE, RELEASE, DELETE, CLOSE, and an OPC interface
to a serial optical bus. Dual control and data paths are established from,
for example, a client system to a single agent on a target system, the
control path including a protocol stack and a data path avoiding at least
one layer of the protocol stack. Packets of control information for a
given process are transferred on the control path, and packets of data
information are transferred on the data path. Communications are
sychronized so that the client and target systems send and receive
communications packets on the same one of the two paths.