User Manual
Chapter 13
GFK-1503F
Jan 2020
Ethernet Communications
228
Range of first integer
Class
0 - 127
A
128 - 191
B
192 - 223
C
224-239
D (Reserved for Multicast Use)
240 - 255
E (Reserved for Experimental Use)
RFC 1918 reserves IP addresses in the following ranges for private networks.
10.0.0.0
–
10.255.255.255
(Class A)
172.16.0.0
–
172.31.255.255
(Class B)
192.168.0.0
–
192.168.255.255 (Class C)
x.y.z.1 is reserved for gateways.
x.y.z.255 is reserved for subnet broadcast
13.3
Routers
Routers connect individual physical networks into a system of networks. When a node on
one network needs to communicate with a node on another network, a Router transfers the
data between the two networks.
Example: Networks Connected by a Router
The following figure shows Network 1 and Network 2 connected by Router R.
Figure 204
Host B can communicate with host C directly because they are on the same network. Their
IP addresses have the same netid.
However, to send data to host A, which is on another network (it has a different netid,) host
B must send it via the router. The router has two IP addresses (172.16.0.1 and 172.17.0.1).
The first is used by hosts on Network 1 and the second is used by hosts on Network 2. In this
example, the router’s IP address on Network 2 is 172.17.0.1. T
his address would be
configured in host B as its default gateway address.