Network+ (Chapter 4 Definitions)

  1. Hub
    An electronic device that sits at the center of a star topology network, providing a common point for the connection of network devices.  In a 10BaseT Ethernet network, the hub contains the electronic equivalent properly terminated bus cable.  Hubs are rare today and have been replaced by switches
  2. Promiscuous Mode
    A mode of operation for a NIC in which the NIC processes all frames taht it sees on the cable.
  3. Sniffer
    Diagnostic program that can order a NIC to run in promiscuous mode.
  4. CSMA/CD
    Access method that Ethernet systems use in LAN technologies, enabling frames of data to flow through the network and ultimately reach address locations.  Known as a contention protocol, hosts on CMSA/CD networks send out data without checking to see if the wire is free first.  If a collision occurs, then both hosts wait a random time period before retransmitting data.
  5. Baseband
    Digital signaling that has only one signal (a single signal) on the cable at a time.  The signals must be in one of three states: one, zero, or idle.
  6. Half-Duplex mode
    Any device that can only send or receive data at any given moment.
  7. Crimper
    Also called a crimping tool, the tool used to secure a crimp (or an RJ-45 connector) onto the end of a cable.
  8. Ethernet
    Name coined by Xerox for the first standard of network cabling and protocols.  Ethernet is based on a bus topology.  The IEEE 802.3 subcommittee defines the current Ethernet specifications.
  9. Media converter
    A device that lets you interconnect different types of Ethernet cable.
  10. Bridge
    A device that connects two networks and passes traffic between them based only on the node address, so that traffic between nodes on one network does not appear on the other network.  For example, an Ethernet bridge only looks at the MAC address.  Bridges filter and forward frames based on MAC addresses and operate at Layer 2 (Data Link Layer) of the OSI seven-layer model.
  11. Uplink port
    Port on a hub that enables you to connect two hubs together using a straight-through cable.
  12. Straight-through cable
    A cable that enables you to connect to uplink ports of two hubs together
  13. Crossover cable
    A special UTP cable used to interconnect hubs/switches or to connect network cards without a hub/switch.  Crossover cables reverse the sending and receiving wire pairs from one end to the other.
  14. Source Address Table (SAT)
    An electronic table of the MAC address of each computer connected to a switch.
  15. Bridge Loop
    A negative situation in which bridging devices (usually switches) are installed in a loop configuration, causing frames to loop continuously.  Switches using Spanning Tree Protocol (STP) prevent bridge loops by automatically turning off looping ports.
Card Set
Network+ (Chapter 4 Definitions)