[CentOS] CentOS 6: ethernet "ifconfig up" failure

On my CentOS 6 partition of my laptop:

First note that for this test, NetworkManager is not
running because I did:
   chkconfig --del NetworkManager
and then rebooted.

Here is my ifcfg-eth0:

DEVICE="eth0"
NM_CONTROLLED="no"
ONBOOT=no
HWADDR=xx:xx:xx:xx:xx:xx
TYPE=Ethernet
BOOTPROTO=none
IPADDR=192.168.2.5
PREFIX=24
GATEWAY=192.168.2.1
DNS1=192.168.2.1
DNS2=192.168.2.1
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=no
NAME="System eth0"
UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

I reboot to level3, do startx (to KDE 4) then do:
# ifconfig eth0 up
# ping 192.168.9.1
connect: Network is unreachable

If I edit ifcfg-eth0 to set
   ONBOOT=yes
and reboot, I get a proper connection.

So why is "ifconfig eth0 up" not connecting?

Thanks for your help.
Mike.