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10-A.1.1: TCP/IP Fundamentals - Identities

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  • Network Nodes

    If the network in question is the Internet or an intranet, many physical network nodes are host computers (also known as Internet nodes) identified by an IP address, and all hosts are physical network nodes. However, some data-link-layer devices such as switches, bridges and wireless access points do not have an IP host address (except sometimes for administrative purposes), and are not considered to be Internet nodes or hosts, but are considered physical network nodes and LAN nodes. In addition to an IP address nodes are known by their physical address, also known as the MAC address. Some nodes may also have an assigned hostname.

    Node Identifier Meaning
    Hostname In computer networking, a hostname (archaically nodename) is a label that is assigned to a device connected to a computer network and that is used to identify the device in various forms of electronic communication, such as the World Wide Web. Hostnames may be simple names consisting of a single word or phrase, or they may be structured.
    MAC Address A media access control address (MAC address) is a unique identifier assigned to a network interface controller (NIC) for use as a network address in communications within a network segment. This use is common in most IEEE 802 networking technologies, including Ethernet, Wi-Fi, and Bluetooth. Within the Open Systems Interconnection (OSI) network model, MAC addresses are used in the medium access control protocol sublayer of the data link layer. As typically represented, MAC addresses are recognizable as six groups of two hexadecimal digits, separated by hyphens, colons, or without a separator.
    IP Address

    An Internet Protocol address (IP address) is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. An IP address serves two main functions: host or network interface identification and location addressing.

    Internet Protocol version 4 (IPv4) defines an IP address as a 32-bit number. A new version of IP (IPv6), using 128 bits for the IP address, was standardized in 1998.

    Network Devices

    Several essential networking devices are used to connect a variety of electronic components to a network. These devices are called network devices, and they transfer data in a fast, secure and correct way over electronic networks.

    Network Device Description
    Network media Refers to the communication channels used to interconnect nodes on a computer network. Typical examples of network media include copper coaxial cables, copper twisted pair cables and optical fiber cables used in wired networks, and radio waves used in wireless data communications networks.
    Bridge A device that connects multiple network segments. It works on OSI layers 1 and 2.
    Switch A device that connects devices together on a computer network by using packet switching to receive, process and forward data to the destination device. Unlike less advanced network hubs, a network switch forwards data only to one or multiple devices that need to receive it, rather than broadcasting the same data out of each of its ports. It works on OSI layer 2.
    Router A networking device that forwards data packets between computer networks. Routers perform the "traffic directing" functions on the Internet. A data packet is typically forwarded from one router to another through the networks that constitute the internetwork until it reaches its destination node. It works on OSI layer 3.
    Gateway An interface providing a compatibility between networks by converting transmission speeds, protocols, codes, or security measures.

    Frames and Packets

    The terms are sometimes used interchangeably except for the layers of the OSI model they operate at. They are both logical grouped units of information with a destination address. A frame operates at the data link layer and often refers to the header and trailer that are used for synchronization and error control. A packet is most often associated with the network layer of the OSI model and includes header information and usually user data. A packet is distinguished by its frame type.

    Adapted from:
    "MAC address" by Multiple ContributorsWikipedia is licensed under CC BY-SA 3.0
    "Hostname" by Multiple ContributorsWikipedia is licensed under CC BY-SA 3.0
    "IP address" by Multiple ContributorsWikipedia is licensed under CC BY-SA 3.0
    "Networking hardware" by Multiple ContributorsWikipedia is licensed under CC BY-SA 3.0
    "Network media" by Multiple ContributorsWikipedia is licensed under CC BY-SA 3.0

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