HP E4510-48G Command Reference Manual page 260

mask-length: Subnet mask length, the number of consecutive ones in the mask.
sub: Secondary IP address for the interface.
Description
Use the ip address command to assign an IP address and mask to the interface.
Use the undo ip address command to remove all IP addresses from the interface.
Use the undo ip address ip-address { mask | mask-length } command to remove the primary IP
address.
Use the undo ip address ip-address { mask | mask-length } sub command to remove a secondary IP
address.
By default, no IP address is assigned to any interface.
When assigning IP addresses to an interface, consider the following:
You can assign only one primary IP address to an interface.
The primary and secondary IP addresses can be located in the same network segment.
Before removing the primary IP address, remove all secondary IP addresses.
You cannot assign a secondary IP address to the interface that is configured to borrow an IP
address through IP unnumbered or obtain one through BOOTP, or DHCP.
Related commands: display ip interface.
Examples
# Assign VLAN-interface 1 a primary IP address 129.12.0.1 and a secondary IP address 202.38.160.1,
with subnet masks being 255.255.255.0.
<Sysname> system-view
[Sysname] interface vlan-interface 1
[Sysname-Vlan-interface1] ip address 129.12.0.1 255.255.255.0
[Sysname-Vlan-interface1] ip address 202.38.160.1 255.255.255.0 sub
1-5