Translation of "downstream system" into Japanese

A client, such as an IBM Communications Manager/2 system, that can access a host connection available on a computer running Host Integration Server 2004. Even though such a client does not use the Host Integration Server 2004 client/server interface, the client can use a downstream connection and a downstream LU to communicate with the host through Host Integration Server 2004. Host Integration Server 2004 passes the information between the downstream system and the host. With Host Integration Server 2004, a downstream system appears to the host as a logical unit, not a physical unit.