. Carriers that own peering points charge other carriers for connections to ports on their routers. However, traffic at these peering centers has the potential to create delays in the Internet if carriers lease too few ports from one another in an attempt to save money. If carriers exchange about the same amount of traffic, they often don't charge one another under this arrangement. Security, routing, traffic policing, and Network Address Translation (NAT) take place at peering points. Address Structures Two universal addressing schemes, IPv4 and IPv6, are used to transmit messages from computers, smartphones, and tablet computers worldwide. The system of routing messages based on IP addresses is managed by 12 organizations that administer 13 clusters of servers, called root servers. The Criticality of Root Servers The root name server system was implemented in the 1990s. The Internet cannot function without root servers, which route messages to the correct organization. Root servers are critical for the sustainability, capacity, and survivability of the Internet. To lessen the system's vulnerability to malicious actions such as Denial-of-Service (DoS) attacks, wherein millions of fake messages bombard a site, root servers balance incoming messages among multiple servers within each root. If one server within the root is brought down, other servers within the root handle the traffic. Ensuring protection against hackers is an ongoing endeavor. The 13 Root Servers Worldwide The Domain Name System (DNS) is the umbrella name of the Internet's capability to translate alpha characters to numeric IP addresses within root servers. Carriers and www.TechnicalPDF.com organizations send traffic addressed to locations outside their networks to one of the 13 sets of root servers, usually the one nearest to them, to determine where to route these messages. The root servers, which are massive databases, translate alphabetic hostnames (gmail.com) into numeric IP addresses (193.22.1.126), and vice versa. Root servers are connected