How to configure multiple IP addresses on same Network card in Linux?

[root@client1 ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth1
DEVICE="eth1"
ONBOOT=yes
TYPE=Ethernet
BOOTPROTO=none
IPADDR=192.168.122.3
PREFIX=24
GATEWAY=192.168.122.1
NAME="System eth1"

[root@client1 ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth1:1
DEVICE="eth1:1"
ONBOOT=yes
TYPE=Ethernet
BOOTPROTO=none
IPADDR=192.168.122.30
PREFIX=24
GATEWAY=192.168.122.1

Once the virtual network interface file is setup correctly, then either restart system or use "service network restart" or use "ifup eth1:1" (whatever suitable & feasible - depends case to case) to bring virtual interface up. It will show up as follows:

[root@client1 ~]# ifconfig -a
eth1      Link encap:Ethernet  HWaddr 52:54:00:18:FB:B0
          inet addr:192.168.122.3  Bcast:192.168.122.255  Mask:255.255.255.0
          inet6 addr: fe80::5054:ff:fe18:fbb0/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:302 errors:0 dropped:0 overruns:0 frame:0
          TX packets:231 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:24975 (24.3 KiB)  TX bytes:33754 (32.9 KiB)
          Interrupt:11 Base address:0x6000

eth1:1    Link encap:Ethernet  HWaddr 52:54:00:18:FB:B0
          inet addr:192.168.122.30  Bcast:192.168.122.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          Interrupt:11 Base address:0x6000

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:16 errors:0 dropped:0 overruns:0 frame:0
          TX packets:16 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:960 (960.0 b)  TX bytes:960 (960.0 b)