RAD-ISM-900-EN-BD…
A-4
PHOENIX CONTACT
2476_en_I
Application
If ANDing the address bits gives the local network address and the local subnetwork
address, the device is located in the local network. If ANDing gives a different result, the
data telegram is sent to the subnetwork router. Figure A-3 shows an example of a Class B
subnet.
Figure A-3
Example for a Class B Subnet Mask
Decimal Notation: 255.255.192.0
Binary Notation: 1111 1111.1111 1111.1100 0000.0000 0000
Using this subnet mask, the TCP/IP protocol software distinguished between devices
that are connected to the local subnetwork and 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 an IP address of 59.EA.55.32. The IP address for
device 2 is displayed as follows:
Hexadecimal Notation: 59.EA.55.3
Binary Notation: 0101 1001.1110 1010.0101 0101.0011 00102
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 mast and IP address for device 2 is as follows:
Subnet Mask: 1111 1111.1111 1111.1100 0000.0000 0000
AND
IP Address:
0101 1001.1110 1010.0101 0101.0011 0010
Result after ANDing:
0101 1001.1110 1010.0100 0000.0000 0000
After ANDing, the software determines that the relevant subnetwork (01) does not
correspond to the local subnetwork (11) and forwards the data telegram to a
subnetwork router.
Class B
Subnet Mask Bits
RSPSupply - 1-888-532-2706 - www.RSPSupply.com
http://www.RSPSupply.com/p-12970-Phoenix-Contact-2900016-Radio-900-MHz-Ethernet-Radio.aspx
