Ericsson ECN330, User Manual

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Glossary
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1553-KDU 137 365 Uen D 2006-06-16
Bandwidth
The difference between the highest and lowest
frequencies available for network signals. Also
synonymous with wire speed, the actual speed
of the data transmission along the cable.
BOOTP
Boot protocol used to load the operating
system for devices connected to the network.
Class of Service (CoS)
CoS is supported by prioritizing packets based
on the required level of service, and then
placing them in the appropriate output queue.
Data is transmitted from the queues using
weighted round-robin service to enforce
priority service and prevent blockage of lower-
level queues. Priority may be set according to
the port default, the packet’s priority bit (in the
VLAN tag), TCP/UDP port number, IP
Precedence bit, or DSCP priority bit.
Collision
A condition in which packets transmitted over
the cable interfere with each other. Their
interference makes both signals unintelligible.
Collision Domain
Single CSMA/CD LAN segment.
CSMA/CD
Carrier Sense Multiple Access/Collision Detect
is the communication method employed by
Ethernet and Fast Ethernet.
Differentiated Services (DiffServ)
DiffServ
provides quality of service on large
networks by employing a well-defined set of
building blocks from which a variety of
aggregate forwarding behaviors may be built.
Each packet carries information (DS byte)
used by each hop to give it a particular
forwarding treatment, or per-hop behavior, at
each network node.
DiffServ
allocates different
levels of service to users on the network with
mechanisms such as traffic meters, shapers/
droppers, packet markers at the boundaries of
the network.
Differentiated Services Code Point
Service (DSCP)
DSCP uses a six-bit tag to provide for up to 64
different forwarding behaviors. Based on
network policies, different kinds of traffic can
be marked for different kinds of forwarding.
The DSCP bits are mapped to the Class of
Service categories, and then into the output
queues.
Domain Name Service (DNS)
A system used for translating host names for
network nodes into IP addresses.
Distance Vector Multicast Routing
Protocol (DVMRP)
A distance-vector-style routing protocol used
for routing multicast datagrams through the
Internet. DVMRP combines many of the
features of RIP with Reverse Path Forwarding
(RPF).