[CentOS] DHCP and no network for long time

Odd thing happened... A centos 7 install set for DHCP. boot the box no
network connected.
I let it like this overnight. I come in this morning and plug in the
network. Is it supposed to get a DHCP address at that time ?  It did not .
service network restart did get an address.

if I unplug the network, reboot the box, want a minute or so - then plug
the network in - it gets a DHCP address.

Is there a "limit" to the time that the OS will keep trying to get a DHCP
address ?

Thanks,

Jerry