User manual

Startup and Functions
7278_en_01 PHOENIX CONTACT 2-5
Application
If the ANDing of the address bits gives the local network address and the local subnetwork
address, the device is located in the local network. If the ANDing gives a different result,
the data telegram is sent to the subnetwork router.
Example for a Class B subnet mask:
Using this subnet mask, the TCP/IP protocol software differentiates between the devices
that are connected to the local subnetwork and the devices that are located in other
subnetworks.
Example: Device 1 wants to establish a connection with device 2 using the above subnet
mask. Device 2 has IP address 59.EA.55.32.
IP address display for device 2:
The individual subnet mask and the IP address for device 2 are then ANDed bit-by-bit by
the software to determine whether device 2 is located in the local subnetwork.
ANDing the subnet mask and IP address for device 2:
After ANDing, the software determines that the relevant subnetwork (01) does not
correspond to the local subnetwork (11) and the data telegram is forwarded to a
subnetwork router.
255.255.192.0
1111 1111.1111 1111.1100 0000.0000 0000
Decimal representation:
Binary representation:
Subnet mask bits
Class B
59.EA.55.32
0101 1001.1110 1010.0101 0101.0011 0010
Hexadecimal representation:
Binary representation:
1111 1111.1111 1111.1100 0000.0000 0000
0101 1001.1110 1010.0101 0101.0011 0010
0101 1001.1110 1010.0100 0000.0000 0000
Subnet mask:
IP address:
Result:
AND
Subnetwork