Γλωσσάρι Δικτυακών Ορολογιών
Προβολή του λεξικού χρησιμοποιώντας αυτό το ευρετήριο
Ειδικά | Α | Β | Γ | Δ | Ε | Ζ | Η | Θ | Ι | Κ | Λ | Μ | Ν | Ξ | Ο | Π | Ρ | Σ | Τ | Υ | Φ | Χ | Ψ | Ω |
L |
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LANLocal-area
network. High-speed, low-error data network
covering a relatively small geographic area (up to a few
thousand meters). LANs connect workstations, peripherals,
terminals, and other devices in a single building or other
geographically limited area. LAN standards specify cabling
and signaling at the physical and data link layers of the
OSI model. Ethernet, FDDI, and Token Ring are widely used
LAN technologies. | |
LAN SwitchHigh-speed switch
that forwards packets between data-link segments. Most LAN
switches forward traffic based on MAC addresses. This
variety of LAN switch is sometimes called a frame switch.
LAN switches are often categorized according to the method
they use to forward traffic: cut-through packet switching or
store-and-forward packet switching. Multilayer switches are
an intelligent subset of LAN switches. | |
LAPBLink Access
Procedure, Balanced. Data link layer protocol in
the X.25 protocol stack. LAPB is a bit-oriented protocol
derived from HDLC. | |
LAPDLink Access
Procedure on the D channel. ISDN data link layer
protocol for the D channel. LAPD was derived from the LAPB
protocol and is designed primarily to satisfy the signaling
requirements of ISDN basic access. Defined by ITU-T
Recommendations Q.920 and Q.921. | |
laserLight
amplification by stimulated emission of radiation.
Analog transmission device in which a suitable active
material is excited by an external stimulus to produce a
narrow beam of coherent light that can be modulated into
pulses to carry data. Networks based on laser technology are
sometimes run over SONET. |
latency1. Delay between the
time a device requests access to a network and the time it
is granted permission to transmit. 2. Delay between the time when a device receives a frame and the time that frame is forwarded out the destination port. |
leased lineTransmission line
reserved by a communications carrier for the private use of
a customer. A leased line is a type of dedicated line. |
line of sightCharacteristic of
certain transmission systems such as laser, microwave, and
infrared systems in which no obstructions in a direct path
between transmitter and receiver can exist. | |
linkNetwork
communications channel consisting of a circuit or
transmission path and all related equipment between a sender
and a receiver. Most often used to refer to a WAN
connection. Sometimes referred to as a line or a transmission
link. | |
LLCLogical Link
Control. Higher of the two data link layer
sublayers defined by the IEEE. The LLC sublayer handles
error control, flow control, framing, and MAC-sublayer
addressing. The most prevalent LLC protocol is IEEE 802.2,
which includes both connectionless and connection-oriented
variants. |
load balancingIn routing, the
ability of a router to distribute traffic over all its
network ports that are the same distance from the
destination address. Good load-balancing algorithms use both
line speed and reliability information. Load balancing
increases the utilization of network segments, thus
increasing effective network bandwidth. |
M |
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MACMedia Access Control.
Lower of the two sublayers of the data link layer defined by the
IEEE. The MAC sublayer handles access to shared media, such as
whether token passing or contention will be used. | |
MAC AddressStandardized data link layer
address that is required for every port or device that connects to a
LAN. Other devices in the network use these addresses to locate
specific ports in the network and to create and update routing
tables and data structures. MAC addresses are 6 bytes long and are
controlled by the IEEE. Also known as a hardware address, a MAC-layer
address, or a physical address. | |
MANMetropolitan-area
network. Network that spans a metropolitan area. Generally,
a MAN spans a larger geographic area than a LAN, but a smaller
geographic area than a WAN | |
MBONEMulticast backbone.
The multicast backbone of the Internet. MBONE is a virtual multicast
network composed of multicast LANs and the point-to-point tunnels
that interconnect them. | |
Mbpsmegabits per second. | |
MD5Message Digest 5.
Algorithm used for message authentication in SNMP v.2. MD5 verifies
the integrity of the communication, authenticates the origin, and
checks for timeliness. | |
meshNetwork topology in which
devices are organized in a manageable, segmented manner with many,
often redundant, interconnections strategically placed between
network nodes. | |
modemModulator-demodulator.
Device that converts digital and analog signals. At the source, a
modem converts digital signals to a form suitable for transmission
over analog communication facilities. At the destination, the analog
signals are returned to their digital form. Modems allow data to be
transmitted over voice-grade telephone lines. |
modulationProcess by which the
characteristics of electrical signals are transformed to represent
information. Types of modulation include AM, FM, and PAM. | |