3Com 10014298 manual Subnet and Mask, Configure IP Address and HostName for a Host

68CHAPTER 4: NETWORK PROTOCOL OPERATION

Subnet and Mask

Configuring an IP Address

■Troubleshooting an IP Address Configuration

IP protocol allocates one IP address for each network interface. Multiple IP addresses can only be allocated to a device which has multiple network interfaces. IP addresses on a device with multiple interfaces have no relationship among themselves.

With the rapid development of the Internet, IP addresses are depleting very fast. The traditional IP address allocation method uses up IP addresses with little efficiency. The concept of mask and subnet was proposed to make full use of the available IP addresses.

A mask is a 32-bit number corresponding to an IP address. The number consists of 1s and 0s. Principally, these 1s and 0s can be combined randomly. However, the first consecutive bits are set to 1s when designing the mask. The mask is divided into two parts, the subnet address and host address. The 1 bits and the mask indicate the subnet address, and the other bits indicate the host address.

If there is no subnet division, then the sub-net mask is the default value and the length of “1” indicates the net-id length. Therefore, for IP addresses of classes A, B and C, the default values of the corresponding sub-net mask is 255.0.0.0 for Class A, 255.255.0.0 for Class B, and 255.255.255.0 for Class C.

The mask can be used to divide a Class A network containing more than 16,000,000 hosts or a Class B network containing more than 60,000 hosts into multiple small networks. Each small network is called a subnet. For example, for the Class A network address 10.110.0.0, the mask 255.255.224.0 can be used to divide the network into 8 subnets: (10.110.0.0, 10.110.32.0, 10.110.64.0, and so on). Each subnet can contain more than 8000 hosts.

The following sections describe the tasks for configuring an IP address:

■Configure IP Address and HostName for a Host

■Configuring the IP Address of the VLAN Interface

■Displaying and Debugging an IP Address

Configure IP Address and HostName for a Host

Perform the following configuration in System view.

Table 62 Configure the Host Name and the Corresponding IP Address

Operation	Command
Configure the host name and the	ip host hostname ip-address
corresponding IP address
Delete the host name and the corresponding	undo ip host hostname [
IP address	ip-address ]

By default, there is no host name associated to any host IP address.

Configuring the IP Address of the VLAN Interface

You can configure an IP address for every VLAN interface of the Ethernet Switch.