network address

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network address serves as a unique identifier for a computer (or other devices) on a network. When set up correctly, computers can determine the addresses of other computers on the network and use these addresses to send messages to each other.

Physical Addresses vs. Virtual Addresses

Most network devices have several different addresses. Physical addresses belong to individual network interfaces attached to a device.

  For example, the Wi-Fi radio and the Bluetooth radio of a mobile device will each possess their own physical network addresses. Separately, virtual addresses can be assigned to devices according to the kind of network they are attached to.  The virtual addresses of a mobile device, for example, change as it migrates from one network to another (while their physical addresses remain fixed).

IP Addresses

The most popular type of virtual network addressing is the Internet Protocol (IP) address. A traditional IP address (IP version 4, IPv4) consists of four bytes (32 bits) that uniquely identify connected devices. Much of the IPv4 address space (the numeric range of address numbers from lowest to highest) is allocated to Internet service providers and other large organizations to assign to their customers and to Internet servers – these are called public IP addresses.  Certain private IP address ranges have also been established to support internal networks (like home networks) with devices that do not need to be directly connected to the Internet.

Some IP networks run the newer Internet Protocol version 6 (IPv6) instead of IPv4. The design of IPv6 incorporates a much larger IP address space than IPv4 to scale up support for many billions of devices. An IPv6 address consists of 16 bytes (128 bits).

MAC Addresses

A well-known form of physical addressing us based on Media Access Control (MAC) technology.

 MAC addresses (also known as “physical addresses”) are six bytes (48 bits) that manufacturers of network adapters embed in their products to uniquely identify them. IP and other protocols rely on physical addresses to identify devices on a network.

Address Assignment

Network addresses are associated with network devices through several different methods:

  • Networks can be configured to assign IP addresses automatically – a process called dynamic address assignment.
  • Network administrators can choose specific IP addresses and assign them to devices manually – a process called static address assignment.
  • Network adapter vendors set a unique MAC address in the read-only memory (ROM) of each unit manufactured - a process sometimes called “burning.”

Home and business networks commonly use Dynamic Host Configuration Protocol (DHCP) servers for automatic IP address assignment.

Network Address Translation

Routers commonly use a technology called Network Address Translation (NAT) to help direct Internet Protocol traffic to its intended destination. NAT works with the virtual addresses contained inside IP network traffic.

Problems with IP Addresses

An IP address conflict occurs when two or more devices on a network both are assigned the same address number.

These conflicts can occur either due to human errors in static address assignment or (less commonly) from technical glitches in automatic assignment systems.