Does “network of source” here mean "possible informants?"
I adopted a similar attitude at the Pentagon. The Department of Defense is an enormous institution—so vast that no Secretary of Defense can possibly know a fraction of what is happening at any given time. Pentagon reporters have a network of sources and are able to discover troubling issues long before they are likely to make their way up to the Secretary of Defense. By identifying problem areas, the press often performs a valuable service both for the Defense Department and for the American people.