Operation Manual –IP Address-IP Performance
H3C S3100 Series Ethernet Switches
Chapter 1 IP Addressing Configuration
1-2
Table 1-1
IP address classes and ranges
Class
Address range
Description
A
0.0.0.0 to 127.255.255.255
Address 0.0.0.0 means this host
no this network. This address is
used by a host at bootstrap
when it does not know its IP
address. 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-zeros 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-zeros host ID: Identifies a network.
z
IP address with an all-ones 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.
Each subnet mask comprises 32 bits related to the corresponding bits in an IP address.
In a subnet mask, the part containing consecutive ones identifies the combination of net
ID and subnet ID whereas the part containing consecutive zeros identifies the host ID.