Operation Manual – IP Addressing and Performance
H3C S3610&S5510 Series Ethernet Switches
Chapter 1 IP Addressing Configuration
1-2
describes the address ranges of these five classes. Currently, the first three
classes of IP addresses are used in quantity.
Table 1-1
IP address classes and ranges
Class
Address range
Description
A
0.0.0.0 to 127.255.255.255
The IP address 0.0.0.0 is used by a
host at bootstrap for temporary
communication. This address is
never a valid destination address.
Addresses starting with 127 are
reserved for loopback test. Packets
destined to these addresses are
processed locally as input packets
rather than sent to the link.
B
128.0.0.0 to 191.255.255.255
––
C
192.0.0.0 to 223.255.255.255
––
D
224.0.0.0 to 239.255.255.255
Multicast address.
E
240.0.0.0 to 255.255.255.255
Reserved for future use except for
the broadcast address
255.255.255.255.
1.1.2 Special Case IP Addresses
The following IP addresses are for special use, and they cannot be used as host IP
addresses:
z
IP address with an all-zero net ID: Identifies a host on the local network. For
example, IP address 0.0.0.16 indicates the host with a host ID of 16 on the local
network.
z
IP address with an all-zero host ID: Identifies a network.
z
IP address with an all-one host ID: Identifies a directed broadcast address. For
example, a packet with the destination address of 192.168.1.255 will be
broadcasted to all the hosts on the network 192.168.1.0.
1.1.3 Subnetting and Masking
Subnetting was developed to address the risk of IP address exhaustion resulting from
fast expansion of the Internet. The idea is to break a network down into smaller
networks called subnets by using some bits of the host-id to create a subnet-id. To
identify the boundary between the host-id and the combination of net-id and subnet-id,
masking is used. (When subnetting is not adopted, a mask identifies the boundary
between the host-id and the host-id.)