Dear Gurus,
I am in deep problem, which seem weird.
last time when I configured a linux router with Centos 6.8 and make vlan subinterfaces its works fine, but now on second machine when I installed centos 6.8 and try to configure vlan subinterfaces, I face problems, details are as.

main interface "eth0" , ifcfg file as,

DEVICE="eth0"
BOOTPROTO="none"
HWADDR="00:01:6C6:CE:A0"
NM_CONTROLLED="no"
ONBOOT="yes"
TYPE="Ethernet"
USRCTL=no
ARPCHECK=no

sub interface "eth0.1" tagged with VLAN file is as,

VLAN="yes"
DEVICE="eth0.1"
ONBOOT="yes"
NM_CONTROLLED="no"
BOOTPROTO="static"
IPADDR="192.168.8.15"
IPV4_FAILURE_FATAL="yes"
IPV6INIT="no"
NETMASK="255.255.252.0"
USRCTL="no"
ARPCHECK="no"

but when I configure this vlan interface my machine stop responding over network, neither network PC able to ping 192.168.8.15
Please help me in this problem, my old machine with same configuration works fine.
switch behind this machine having trunk is OK and interface attached with eth0 configured as trunk with allowed all vlans.

prompt response shall be highly appreciated.

Can you show us the defined network interfaces?
Then active interfaces only
BTW vlan ID 1 is usually reserved/used for administrative purposes.