VEGA VEGACOM 558 Ethernet - Manual (Page 36)

36 VEGACOM 558 Ethernet
Subnets with VEGACOM 558
For the use of subnet masks with VEGACOM 558, the same rules as for
any Ethernet host apply. A host only processes telegrams whose desti-
nation addresses have full compliance with their own subnet. A specific
subnet is determined by its own IP address and the subnet mask. By
AND linking of IP address and subnet mask, you will get the appropri-
ate subnet. In other words, all bit positions of the subnet mask set at "1",
determine the NetID, i.e. the subnet. The more bit positions used for the
determination of the NetID, the less combinations remain for the HostID.
Example:
VEGACOM 558 IP address:
192.168.200.1 (Class-C)
Standard masking (subnet mask): 255.255.255.0
This means for VEGACOM 558:
- VEGACOM 558 is in the subnet 192.168.200.0 (with max. 253 partici-
pants)
- VEGACOM 558 processes all telegrams on the Ethernet whose desti-
nation addresses start with 192.168.200.
- VEGACOM 558 itself can only transmit telegrams whose destination
addresses start with 192.168.200
Improved masking by e.g.: 255.255.255.128
This means for VEGACOM 558:
- By setting an additional bit in the subnet mask, the above-mentioned
subnet will be divided into two sections.
- VEGACOM 558 is now in subnet 192.168.200.0 (with max. 126 partici-
pants)
- VEGACOM 558 processes all telegrams on the Ethernet whose desti-
nation addresses are between 192.168.200.1 and 192.168.200.127.
- VEGACOM 558 itself can only drop off telegrams whose destination
addresses are between 192.168.200.1 and 192.168.200.127
VEGACOM 558 as web server