Installation guide

88 Chapter 4
Configuring I/O Interfaces
Configuring LAN Interfaces
The LAN software is built on top of standard LAN networking protocols.
There are two LAN networking protocols provided with the Agilent IO
Libraries software. You can use one or both of these protocols when
configuring your systems (via Agilent IO Libraries configuration) to use
VISA and SICL over LAN.
n SICL-LAN Protocol is a networking protocol developed by Agilent
that is compatible with all VISA LAN products. This LAN networking
protocol is the default choice in the Agilent IO Libraries configuration
when configuring the LAN client. The SICL LAN protocol on HP-UX
10.20, Windows 95/98/Me/2000/NT supports VISA operations over
LAN to GPIB interfaces.
n VXI-11 (TCP/IP Instrument Protocol) is a networking protocol
developed by the VXIbus Consortium based on the SICL LAN
Protocol that permits interoperability of LAN software from different
vendors who meet the VXIbus Consortium standards.
When using either of these networking protocols, the LAN software uses the
TCP/IP protocol suite to pass messages between the LAN client and the
LAN server. The server accepts device I/O requests over the network from
the client and then proceeds to execute those I/O requests on a local
interface (GPIB, etc.).
By default, the LAN Client supports both protocols by automatically
detecting the protocol the server is using. When a VISA viOpen or SICL
iopen call is performed, the LAN Client driver first tries to connect using the
SICL-LAN protocol. If that fails, the driver will try to connect using the VXI-11
protocol.
If you want to control the protocol used, you can configure more than one
LAN Client interface and set each interface to a different protocol. The
protocol used will then depend on the interface you are connecting through.
Thus, you can have more than one SICL-LAN and one VXI-11 protocols for
your system.
In VISA, the protocol used is determined by the configuration settings and
cannot be changed programatically. In SICL, the programmer can override
the configuration settings by specifying the protocol in the iopen string.
Some examples are: