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Appendix C

Glossary
1000BASE-SX: A short laser wavelength on multimode fiber optic cable for a m aximum length of 500 meters
1000BASE-LX: A long wavelength for a "long haul" fiber optic cable for a m aximum length of 10 kilometers
1000BASE-T: 1000Mbps Ethernet implementation over Category 5E cable.
100BASE-FX: 100Mbps Ethernet implementation over fiber.
100BASE-TX: 100Mbps Ethernet implementation over Category 5 and T ype 1 Twisted Pair cabling.
10BASE-T: The IEEE 802.3 specification for Ethernet over Unshielded Twisted Pair ( UTP) cabling.
aging: The automatic removal of dynamic entries from the Switch Database which ha ve timed-out and are no longer valid.
ATM: Asynchronous Transfer Mode. A connection oriented trans mission protoc ol based on fix ed length cells ( packets) . ATM is
designed to carry a complete range of user traffic, including voice, data and video signals.
auto-negotiation: A feature on a port, which allows it to advertise its capabilities for speed, duplex and flow control. When
connected to an end station that also supports auto-negotiation, the link can self-detec t its optimum operating setup.
backbone port: A port which does not learn device addresses, and which receives all frames with an unk nown address.
Backbone ports are normally used to connect the Switch to the bac kbone of your network. Note that back bone ports were
formerly known as designated downlink ports.
backbone: The part of a network used as the primary path for transporting traf fic between network segments.
bandwidth: Information capacity, measured in bits per second that a channel can transm it. The bandwidth of Ethernet is
10Mbps, the bandwidth of Fast Ethernet is 100Mbps.
baud rate: The switching speed of a line. Also known as line speed between network segments.
BOOTP: The BOOTP protocol allows you to automatically map an IP address to a giv en MAC address each tim e a device is
started. In addition, the protocol can assign the subnet mask and defau lt gateway to a device.
bridge: A device that interconnects local or remote networks no matter what higher-level protocols are involved. Bridges form a
single logical network, centralizing network administration.
broadcast: A message sent to all destination devices on the network.
broadcast storm: Multiple simultaneous broadcasts that typically absorb available network band width and c an cause network
failure.
console port: The port on the Switch accepting a terminal or modem connector. It changes the par allel arrangement of data
within computers to the serial form used on data transmission link s. This port is most often used for dedicated local
management.
CSMA/CD: Channel access method used by Ethernet and IEEE 802.3 standards in which devices transmit only after finding the
data channel clear for some period of time. When two devices tr ansmit simultaneously, a collision occurs and the colliding
devices delay their retransmissions for a random amount of time.
data center switching: The point of aggregation within a corporate network where a switch provides high-pe rform ance access
to server farms, a high-speed backbone connection and a control point for net work management and security.
Ethernet: A LAN specification developed jointly by Xerox, Intel and Digital Equipment Cor poration. Ethernet network s operate
at 10Mbps using CSMA/CD to run over cabling.
Fast Ethernet: 100Mbps technology based on the Ethernet/CMSA/CD network access method.
Flow Control: (IEEE 802.3z) A means of holding packets back at the transmit port of the c onnected end station. Prevents
packet loss at a congested switch port.
forwarding: The process of sending a packet toward its destination by an internetwork ing device.
full duplex: A system that allows packets to be transmitted and received at the same time and, in eff ect, doubles the pot ential
throughput of a link.
half duplex: A system that allows packets to be transmitted and received, but not at the s ame time. Contrast with full duplex.
IP address: Internet Protocol address. A unique identifier for a device attached to a network using TCP/IP. The address is
written as four octets separated with full-stops (periods), and is m ade u p of a net wor k section, an opt iona l subnet sec tion and a
host section.
IPX: Internetwork Packet Exchange. A protocol allowing communicat ion in a NetWare network.