H3C Technologies H3C S10500 Series Switches - Manual (Page 36)

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• With subnetting: Using the first 9 bits of the host-id for subnetting provides 512 (2 9 ) subnets.
However, only 7 bits remain available for the host ID. This allows 126 (2 7 – 2) hosts in each subnet,
a total of 64,512 hosts (512 × 126).
Configuring IP addresses
An interface must have an IP address to communicate with other hosts. You can either manually assign
an IP address to an interface, or configure the interface to obtain an IP address through DHCP. If you
change the way an interface obtains an IP address, the new IP address will overwrite the previous one.
NOTE:
This chapter only covers how to assign an IP address manually. For information about how to obtain an IP
address through DHCP, see the chapters “DHCP overview”.
Assigning an IP address to an interface
You may assign an interface one primary and multiple secondary addresses.
Generally, you only need to assign the primary address to an interface. In some cases, you need to
assign secondary IP addresses to the interface. For example, if the interface connects to two subnets, to
enable the device to communicate with all hosts on the LAN, you need to assign a primary IP address
and a secondary IP address to the interface.
Follow these steps to assign an IP address to an interface:
To do… Use the command… Remarks
Enter system view system-view ––
Enter interface view
interface interface-type
interface-number
––
Assign an IP address to the
interface ip address ip-address { mask-length
| mask } [ sub ] Required
No IP address is assigned by default.
CAUTION:
•
Each interface has only one primary IP address. A newly configured primary IP address overwrites the
previous one.
• You cannot assign secondary IP addresses to an interface that obtains an IP address through DHCP.
• The primary and secondary IP addresses you assign to the interface can be located on the same
network segment, but different interfaces on your device must reside on different network segments.
IP addressing configuration example
Network requirements
As shown in Figure 15 , a port in VLAN 1 on a switch is connected to a LAN comprising two segments:
172.16.1.0/24 and 172.16.2.0/24.
To enable the hosts on the two subnets to communicate with the external network through the switch, and
to enable the hosts on the two subnets to communicate with each other: