FAQs from Rohde & Schwarz

Remote Control: Interaction between TCP/IP Address and Subnet Mask


I want to remote-control via LAN a device from a PC. The PC and the device have their own TCP/IP addresses, but I get no connection when I use those addresses. Which function does the Subnet Mask have?


The controller can establish a connection via LAN in two different ways:

It can query its local network to find a device with the defined TCP/IP address or ask a host server to search for a device with this TCP/IP address in other networks.

The method the controller uses depends on the TCP/IP address and the Subnet Mask.

The TCP/IP address and the Subnet Mask have the same format:


xxx can be any value between 0 and 255 for the TCP/IP address, but there are only three possibilities for the Subnet Mask :




You define the size of the local network by specifying which of the four numbers of the TCP/IP address has to be identical for all members of the local network.

With a) the first number has to be identical, with b) the first two and with c) the first three numbers (defined by 255).