An IP address is a unique numeric identifier for a computer or other device on a TCP/IP network. TCP/IP (transmission control protocol/Internet protocol) is the set of protocols (i.e., agreed upon formats) that is used for the Internet as well as for most LANs (local area networks) and other computer networks. Show
In IPv4, the current standard protocol for the Internet, each IP address consists of 32 bits. They are expressed as four sets of numbers, each between 0 and 255, which are separated by periods. Examples are 115.25.3.108 and 127.0.0.1; the latter is the so-called loopback address, which returns messages to the same computer that sent them and is used for testing purposes and by some applications. 32 bits allows the creation of more than four billion (exactly 4,294,967,296) unique addresses. However, in practice, the address space is sparsely populated due to routing issues. Routing, which is usually performed by a dedicated device called a router, is the process of moving packets (i.e., the most basic unit of data transmission) from source to destination. Thus there is some pressure to extend the address range though the use of IPv6, which is the next-generation Internet protocol. IPv4 addresses originally had only two parts, but a later change increased that to three: network, the subnetwork and host, in that order. However, the introduction of CIDR (classless inter-domain routing) now allows addresses to have any number of levels of hierarchy. Within an isolated network, IP addresses can be assigned at random as long as each one is unique. However, for computers connected to the Internet, it is necessary to use registered IP addresses in order to avoid duplicates. A static IP address is an IP address for a computer or other device that remains the same every time the device is connected to the network and does not change unless it is changed manually. A dynamic IP address is one that changes every time a device is connected to the network and which is assigned by the dynamic host configuration protocol (DHCP). The dynamic assignment of IP addresses can eliminate the need for system administrators to assign them manually and is a way to make more efficient use of the limited number of IP addresses available to individual ISPs (Internet service providers), businesses and other organizations. Users of dial-up connections to the Internet generally receive dynamically generated IP addresses, whereas users of DSL and cable connections typically are assigned one or more static IP addresses. IP address assignments are made by registry organizations, such as ARIN (American Registry for Internet Numbers), in response to requests from ISPs and other organizations for a netblock (a range of consecutive IP addresses). If an organization has exhausted a substantial part of its allocated netblock, it can request another. IPv6, which is expected to be slowly phased in over the next five to 15 years, features a 128-bit addressing scheme that allows for a vastly increased number of unique addresses (18,445,618,199,572,250,625). This will facilitate creation of the so-called Internet of things, which will allow a vast array of objects in addition to computers to be connected to the Internet. IPv5 exists only on an experimental basis and will not be deployed for general use. Created September 23, 2005. Updated July 12, 2006. Article 3 of 6 Part of: The fundamentals of computer networking
A MAC address and an IP address each identify network devices, but they do the job at different levels. Explore the differences between the two and learn why both are necessary.Every computer or device on the internet has two types of addresses: its physical address and its internet address. The physical address -- which is also called a media access control, or MAC, address -- identifies a device to other devices on the same local network. The internet address -- or IP address -- identifies the device globally. A network packet needs both addresses to get to its destination. MAC address vs. IP address: What's the difference?Both MAC addresses and IP addresses are meant to identify a network device, but in different ways. Some of the main differences between a MAC address and an IP address include the following:
A MAC address is responsible for local identification and an IP address for global identification. This is the primary difference between a MAC address and IP address, and it affects how they differ in their number of bits, address assignment and interactions. The MAC address is only significant on the LAN to which a device is connected, and it is not used or retained in the data stream once packets leave that network. Any piece of internet software, such as a web browser, directs data to a destination on the internet using the destination's IP address. That address is inserted into the data packets that the network software stack sends out. People rarely use the address numbers directly, instead using DNS names, which the application translates into the matching number. Internet routers move the packets from the source network to the destination network and then to the LAN on which the destination device is connected. That local network translates the IP address to a MAC address, adds the MAC address to the data stream and sends the data to the right device.  Another difference between a MAC address and IP address is the way the addresses are assigned. An IP address is bound to a network device via software configurations, and network administrators can change it at any time. Local network switches maintain Address Resolution Protocol (ARP) tables that map IP addresses to MAC addresses. When a router sends the switch a packet with a destination specified by an IP address, it uses the ARP table to know which MAC address to attach to the packet when it forwards the data to the device as Ethernet frames. What is a MAC address?Media access control refers to the piece of hardware that controls how data is pushed out onto a network. In the OSI reference model for networking, the MAC is a Layer 2 -- or data link layer -- device, and the MAC address is a Layer 2 address. In the current internet era, most devices are connected physically with Ethernet cables or wirelessly with Wi-Fi. Both methods use MAC addresses to identify a device on the network.
A MAC address consists of 12 hexadecimal digits, usually grouped into six pairs separated by hyphens. MAC addresses are available from 00-00-00-00-00-00 through FF-FF-FF-FF-FF-FF. The first half of the number is typically used as a manufacturer ID, while the second half is a device identifier. In nearly all enterprise network devices today, whether Wi-Fi or Ethernet, this number is hardcoded into the device during the manufacturing process. Each MAC address is unique to the network card installed on a device, but the number of device-identifying bits is limited, which means manufacturers do reuse them. Each manufacturer has about 1.68 million available addresses, so when it burns a device with a MAC address ending in FF-FF-FF, it starts again at 00-00-00. This approach assumes it is highly unlikely two devices with the same address will end up in the same local network segment. No two devices on a local network should ever have the same MAC address. If that does happen, both devices will have communications problems because the local network will get confused about which device should receive the packet. When a switch broadcasts a packet to all ports in order to find the intended recipient, whichever device responds first will receive the packet stream directed to it. If the device reboots, is taken away or shuts down, the other node may then receive the packets. What is an IP address?IP controls how devices on the internet communicate and defines the behavior of internet routers. It corresponds to Layer 3, the network layer, of the OSI reference model. The internet was initially built around IP version 4 (IPv4) and is in transition to IPv6. An IP address identifies a device on the global internet, acting as the device's logical address to identify that network connection. An IPv4 address consists of 32 bits, usually written as four decimal numbers, or a dotted quad. Possible values range from 000.000.000.000 through 255.255.255.255, although many possible addresses are disallowed or reserved for specific purposes. The address combines network identification and device identification data. The network prefix is anywhere from eight to 31 bits, and the remainder identify the device on the network. Steady, rapid growth in the number of internet-connected devices has led to the looming exhaustion of the IPv4 address list, one of several reasons for the development of IPv6. An IPv6 address consists of 128 bits, with the first 64 reserved for network identification and the second 64 dedicated to identifying a device on the network. The address is written as eight sets of four hexadecimal digits separated by colons -- for example, FEDC:BA98:7654:3210:0123:4567:89AB:CDEF. Happily, many conventions are available to shorten an IPv6 address when writing it.
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What are the unique network identifiers?Unique identifiers or UID's are numbers and letters that allow the identification of objects within a computer system. They indicate where an object is located and how it can be reached. Unique identifiers allow the control and interaction of different objects or abstract datasets within a computer network.
Is an identifier which is assigned to each computer and other components?An IP address (abbreviation of Internet Protocol address) is an identifier assigned to each computer and other device (e.g., printer, router, mobile device, etc.)
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