An Ethernet IP address is a 4-byte value that is displayed in dotted decimal notation:
Example: 10. 1. 0. 9
This address contains two pieces of information: the network ID and the host ID.
Network ID
Typically, the first one to three bytes of the IP address are the network ID. This ID identifies a group of computers and other devices (such as SIXNET Ethernet stations and I/O modules) that are all located on the same logical network. In internetworks (networks formed by a collection of local area networks), there is a unique network ID for each network.
SIXNET Ethernet stations and I/O modules have a one-byte Network ID of ‘10. x. x. x’ by default, unless the Automatically Assign IP Address checkbox (in the Main Port Setup window) is cleared. This Network ID may or may not be acceptable for your network. Refer to the Assigning IP Addresses topic for more information.
Host ID
The last one to three bytes of the IP address are the host ID. This ID identifies your computer or SIXNET Ethernet station or I/O module within a particular network ID. (A host is any device that is attached to the network and uses TCP/IP protocol.)
SIXNET Ethernet stations and I/O modules have a three-byte Host ID of ‘10. 1. y. z’ by default, unless the Automatically Assign IP Address checkbox (in the Main Port Setup window) is cleared. The first byte of the ID defaults to a value of 1. The last two bytes (y and z) are assigned based upon the station number of the station or I/O module.