The problem of treating a set of local area networks (LANs) as one Internet network has generated some interest and concern. It is inappropriate to give each LAN within an site a distinct Internet network number. It is desirable to hide the details of the interconnections between the LANs within an site from people, gateways, and hosts outside the site. The question arises on how to best do this, and even how to do it at all. In RFC-917 Jeffery Mogul makes a case for the use of "explicit subn...