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DGS-3048 Gigabit Ethernet Switch Manual
114
C
Glossary
1000BASE-T –
A specification for Gigabit Ethernet over copper wire (IEEE Std. 802.3ab). The standard defines 1
Gb/s data transfer over distances of up to 100 meters using four pairs of CAT-5 balanced copper cabling and a 5-level
coding scheme. Its benefits include compatibility with existing network protocols (i.e. IP, IPX, AppleTalk), existing
applications, Network Operating Systems, network management platforms and applications.
100BASE-TX
– 100Mbps Ethernet implementation over Category 5 and Type 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– The automatic removal of dynamic entries from the Switch Database which have timed-out and are no longer
valid.
ATM
– Asynchronous Transfer Mode. A connection oriented transmission protocol based on fixed 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 that 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-detect its optimum operating
setup.
backbone
– The part of a network used as the primary path for transporting traffic
backbone port
– A port that does not learn device addresses, and receives all frames with an unknown address.
Backbone ports are normally used to connect the Switch to the backbone of your network. Note that backbone ports
were formerly known as designated downlink ports.
bandwidth
– Information capacity, measured in bits per second, that a channel can transmit. The bandwidth of
Ethernet is 10Mbps and the bandwidth of Fast Ethernet is 100Mbps.
baud rate
– The switching speed of a line. Also known as
line speed
between network segments.
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 bandwidth and can cause
network failure.
console port
– The port on the Switch accepting a terminal. It changes the parallel arrangement of data within
computers to the serial form used on data transmission links. 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 transmit 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-
performance access to server farms, a high-speed backbone connection and a control point for network management
and security.
Ethernet
– A LAN specification developed jointly by Xerox, Intel and Digital Equipment Corporation. Ethernet
networks operate at 10Mbps using CSMA/CD to run over cabling.
Fast Ethernet
– 100Mbps technology based on the Ethernet/CD network access method.
Flow Control
– (IEEE 802.3z) A means of holding packets back at the transmit port of the connected end station.
Prevents packet loss at a congested Switch port.
forwarding
The process of sending a packet toward its destination by an internetworking device.
full duplex
– A system that allows packets to be transmitted and received at the same time and, in effect, doubles the
potential throughput of a link.
GBIC
– Gigabit interface converter, a transceiver that converts serial electric signals to serial optical signals and vice
versa. In networking, a GBIC is used to interface a fiber optic system with an Ethernet system, such as Fiber Channel
and Gigabit Ethernet.