R&S EB200 Manual page 198

EB200 Manual Remote control
Sockets:
The remote clients are connected to the host computer by so-called sockets. These are logic point-to-
point links that are independent of the transmission medium used. Sockets are based on the
Transmission Control Protocol (TCP) or the User Datagram Protocol (UDP). These two protocols are in
turn based on the Internet Protocol (IP). The following figure shows the layer model of the sockets.
Sockets
TCP UDP
IP
PPP
Ethernet RS232
The transmission media are located beneath the IP layer. EB200 is fitted with an RS232-compatible
interface as standard. This interface is coupled to the IP layer by means of the Point-to-Point Protocol
(PPP). This is necessary because IP is a packet-oriented protocol. It is not necessary if the optional
LAN interface is used, because the Ethernet protocol of this interface is already packet-oriented
The use of sockets has several advantages:
• the protocols used (PPP, IP, TCP, UDP) are standardized and implemented on all customary
operating systems (WindowsNT, Windows95, Windows 3.1, UNIX, SunOS, and many more).
• TCP links are protected against transmission errors.
• Host software can be generated independent of the transmission medium used (LAN or RS232).
• Several logic links may use the same transmission medium.
• IP routing enables access also to remote units also over great distances (eg via the Internet).
When the unit is started, a so-called list socket is generated. It functions as the unit's "receptionist".
Each host wishing to remote-control the EB200 has to log in with the list socket first. The list socket
then generates a new remote client and allocates the link to a new socket so the list socket remains
free to receive further hosts.
For login at the list socket, the host needs to have the address and port number of the unit. This can be
set in the Setup Remote menu.
4052.2000.02 4.124 E-7