1. Fbb-x900 Ethernet
  2. Parameterisation and Commissioning
  3. IP Address
  4. Network Classes

Network Classes

Three different network classes are distinguished. They specify how many address bits are reserved for the Network -ID and how many for the computer number (or node number). The difference is located in the first 3 bits of the IP address.

Network-
class

Number of bits
for the Network ID

Possible number
of networks

Number of bits for
the node address

Possible number of
nodes per network

A

7

126

24

16 777 214

B

14

16 382 

16

65 536

C

21

2 097 150 

8

254

 

Note
Warning

An IP address must be unique within the entire connected network!

 

 

Note

In a communication with another Ethernet devices, the IP address set must have the same network class. Example: Your PC has address 172.16.17.55, which means that the Bus Coupler must have address 172.16.xxx.xxx (each xxx stands for a number between 0...255. The 0 is normally used for routers/switches, and should therefore be reserved).

In order to see the PC's own address, the command ipconfig can be entered into a DOS window under Windows NT/2000/XP.