Delta RMC151 - Manual (Page 449)

6 Communication
Value
IP Address 192.168.0.5 C0A80005
Subnet Mask 255.255.255.0 FFFFFF00
Network
Address
192.168.0 C0A800
Local Address 5 05
Therefore, from this example, we see that a device with an IP address of 192.168.0.5 and
subnet mask of 255.255.255.0 will have a network address of 192.168.0 and a local
address of 5. Other devices on this network must have the same network address but
different local addresses. Therefore, some possible IP addresses for other nodes on the
network include 192.168.0.6, 192.168.0.1, and 192.168.0.25. There are two reserved
local addresses: a local address with all zero bits refers to the network (e.g.
192.168.0.0), and a local address with all one bits is the broadcast address for the
network (e.g. 192.168.0.255).
Default Gateway
Suppose the device given in the above example must communicate with a device on a
connected network with an IP address of 192.168.1.8. Because the device is not on the
same network there is no electrical connection between the computers so it cannot send
its data directly. Instead it must go through an IP router. An IP router is a device that
sends packets it receives from one network that are intended for devices on another
network to the other network. Here is the example intranet:
How does 192.168.0.5 send a message to 192.168.1.8? The answer is that it must use a
third parameter called the default gateway. This parameter is the IP address of the router
who will take care of getting the packet to its destination. The rule for most devices is to
send packets to devices with the same network address directly over its network, but to
send packets to devices with a different network address to the default gateway. In the
above network, the device at 192.168.0.5 would have a default gateway of 192.168.0.1,
and the device at 192.168.1.8 would have a default gateway of 192.168.1.1.
The default gateway parameter is optional if the device will be on a network that is not
connected to any other networks, or if you have an intranet but do not want to allow the
device to communicate with devices on networks other than its own.
6.8.9.3. Ethernet MAC Address
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