Glossary
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NS3550-8T-2S Industrial Managed Switch User Manual
QCL
QoS Control List. It is the list table of QCEs, containing QoS
control entries that classify a specific QoS class on specific
traffic objects.
Each accessible traffic object contains an identifier to its QCL.
The privileges determine specific traffic object to specific QoS
class.
QL
QL In SyncE is the Quality Level of a given clock source. This
is received on a port in a SSM indicating the quality of the
clock received in the port.
QoS
Quality of Service. It is a method to guarantee a bandwidth
relationship between individual applications or protocols.
A communications network transports a multitude of
applications and data, including high-quality video and delay-
sensitive data such as real-time voice. Networks must provide
secure, predictable, measurable, and sometimes guaranteed
services, and QoS can help to provide this.
QoS Class
Every incoming frame is classified to a QoS class, which is
used throughout the device for providing queuing, scheduling,
and congestion control guarantees to the frame according to
what was configured for that specific QoS class. There is a one
to one mapping between QoS class, queue, and priority. A
QoS class of 0 (zero) has the lowest priority.
R
RARP
Reverse Address Resolution Protocol. It is a protocol that is
used to obtain an IP address for a given hardware address,
such as an Ethernet address. RARP is the complement of
ARP.
RADIUS
Remote Authentication Dial In User Service. It is a networking
protocol that provides centralized access, authorization, and
accounting management for people or computers to connect to
and use a network service.
RDI
Remote Defect Indication. It is a OAM functionallity that is used
by a MEP to indicate defect detected to the remote peer MEP.
Router Port
A router port is a port on the Ethernet switch that connects it to
the Layer 3 multicast device.
RSTP
In 1998, the IEEE with document 802.1w introduced an
evolution of STP: the Rapid Spanning Tree Protocol, which
provides for faster spanning tree convergence after a topology
change. Standard IEEE 802.1D-2004 now incorporates RSTP
and obsoletes STP, while at the same time being backwards-
compatible with STP.