Clarify NTP server requirement

Author: jeana-redhat

modules/ipi-install-network-requirements.adoc

@@ -9,7 +9,7 @@ Installer-provisioned installation of {product-title} involves several network r
 
 .Network Time Protocol (NTP)
 
-Each {product-title} node in the cluster must have access to an NTP server.
+It is recommended that each {product-title} node in the cluster have access to a Network Time Protocol (NTP) server that is discoverable using DHCP. While installation without an NTP server is possible, asynchronous server clocks can cause errors. Using an NTP server can prevent this issue.
 
 .Configuring NICs