3Com 8807 Configuration Manual page 72

72 C 10: IP A
HAPTER DDRESS
Subnet and Mask
C
ONFIGURATION
Table 52 IP address classes and ranges
Network Address
class range
0.0.0.0 to
A 127.255.255.
255
128.0.0.0 to
B 191.255.255.
255
192.0.0.0 to
C 223.255.255.
255
224.0.0.0 to
D 239.255.255.
255
240.0.0.0 to
E 255.255.255.
254
Other 255.255.255.
addresses 255
Nowadays, with rapid development of the Internet, IP (V4) addresses are depleting
very in a few years. The traditional IP address allocation method wastes IP
addresses greatly. In order to make full use of the available IP addresses, the
concept of mask and subnet is proposed.
IP network
range
available Note
Host ID with all the digits being 0 indicates
that the IP address is the network address,
and is used for network routing.
Host ID with all the digits being 1 indicates the
broadcast address, that is, broadcast to all
hosts on the network.
IP address 0.0.0.0 is used for the host that is
not put into use after starting up.
1.0.0.0 to
126.0.0.0 The IP address with network ID being 0
indicates the current network and its network
can be cited by the router without knowing its
network number.
The IP addresses with the format of 127.X.Y.Z
are reserved for self-loop test and the packets
sent to these addresses are not output to the
line. The packets are processed internally and
regarded as input packets.
Host ID with all the digits being 0 indicates
that the IP address is the network address,
and is used for network routing.
128.0.0.0 to
191.254.0.0
Host ID with all the digits being 1 indicates the
broadcast address, that is, broadcast to all
hosts on the network.
Host ID with all the digits being 0 indicates
that the IP address is the network address,
192.0.0.0 to
and is used for network routing.
223.255.254.
Host ID with all the digits being 1 indicates the
0
broadcast address, that is, broadcast to all
hosts on the network.
Addresses of class D are multicast addresses,
among which:
IP address 224.0.0.0 is reserved and will
■
not be allocated. Those from 224.0.0.1 to
224.0.0.255 are reserved for routing
protocols and other protocols that are
None
used to discover and maintain routes.
Those from 239.0.0.0 to 239.255.255.255
■
are used for local multicast management.
Those from 224.0.0.255 to
■
238.255.255.255 are for users.
None The addresses are reserved for future use.
255.255.255. 255.255.255.255 is used as a Local Area
255 Network (LAN) broadcast address.