CentOS 7 - Network unreachable for Class A or B subnets

ISSUE

With initial IP setup not able to route IP traffic for subnets not the default /24 (255.255.255.0)

RESOLUTION

From command line run through the following:

edit ifcfg for adapter (example: ifcfg-ens192 )

vi /etc/sysconfig/network-scripts/ifcfg-ens192

edit PREFIX="24" to correct slash notation 

then save and restart network services 

CAUSE

found PREFIX='24' defaulting the NIC setup to subnet 255.255.255.0 regardless of assignment in dpuconfig or UI eth assignments.