D-Link DES-1048G, Manual

D-Link DES-1048G Unmanaged Layer 2 Ethernet Switch

Glossary 

1000BASE-SX –  

1000Mbps Ethernet implementation over fiber-optic cable, intended for shorter distances, 

such as within a building.

1000BASE-LX –  

1000Mbps Ethernet implementation over fiber-optic cable, for longer distances, such as a 

college campus.

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no longer valid.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 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-detect 
its optimum operating setup.  

backbone

 – The part of a network used as the primary path for transporting traffic 

backbone port

 – A port which does not learn device addresses, and which 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. 

BOOTP

 – The BOOTP protocol allows you to automatically map an IP address to a given MAC address 

each time a device is started. In addition, the protocol can assign the subnet mask and default 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 bandwidth and 

can cause network failure. 

console port

 – The port on the switch accepting a terminal or modem connector. 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. 

half duplex

 – A system that allows packets to be transmitted and received, but not at the same time. 

Contrasts with full duplex. 

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