The Differences between the NetBIOS Naming System and DNS

The Differences between the NetBIOS Naming System and DNS

                                                                                                      The naming system used by DNS is a hierarchical namespace, called the DNS namespace. The DNS namespace has a unique root. The root can contain numerous subdomains. Each subdomain also can contain multiple subdomains. The DNS namespace uses a logical tree structure wherein an entity is subordinate to the entity which resides over it. Each node in the DNS domain tree has a name, which is called a label. The label can be up to 63 characters. Nodes that are located on the same branch within the DNS domain tree must have different names. Nodes that reside on separate branches in the DNS hierarchy can have the same name.

Each node in the DNS domain tree or DNS hierarchy is identified by a FQDN. This is a DNS domain name that specifies the node.s location in relation to the DNS domain tree/hierarchy. A domain name can be defined as the list of labels along the path from the root of the DNS domain tree/hierarchy to a particular node. The FQDN is the entire list of labels for a specific node.

Each domain registered in DNS is connected to a DNS name server. The DNS server of a domain provides authoritative replies to queries for that particular domain.

Internet Corporation for Assigned Names and Numbers (ICANN) manages the DNS root of the Internet domain namespace. ICANN manages the assignment of globally unique identifiers which are key to the operation of Internet. This includes the following components:

• Internet domain names
• IP addresses
• Port numbers
• Protocol parameters

Below the root DNS domain are the top-level domains. These top-level domains are also managed by ICANN. The top-level domains managed by ICANN are:

• Organizational domains: Organizational domains have the following characteristics:
• Organizational domains can be used globally.
• They are named via a three-character code.
• The code defines the main function of the organizations of the DNS domain.
• Geographical domains: Geographical domains have the following characteristics:
• Geographical domains are usually used by organizations not residing in the United States.
• They are named via a two-character country and region codes.
• The codes were established by the International Organization for Standardization (ISO) 3166.
• The codes identify a country, such as .uk for the United Kingdom
• Reverse domains: These domains are used for IP address to name mappings. This is called reverse lookups.

The additional top-level domains defined by ICANN in late 2000 are:

• .aero; for the air transportation industry
• .biz; for businesses
• .coop; for cooperatives
• .info; for information
• .museum; for museums
• .name; for individual names
• .pro; for credentialed professions such as attorneys.

The common top-level domain names used are:

• .com; commercial organizations
• .edu; for educational institutes.
• .gov; for government.
• .int; for international organizations.
• .mil; for military organizations
• .net; for Internet providers, and networking organizations
• .org; non-commercial organizations
• .uk; United Kingdom
• .us; United States
• .ca; Canada
• .jp; Japan