Netgear GS728TP100NAS 사용자 설명서

다운로드
페이지 530
331
5
5.   
Configuring Quality of Service
Use the features in the QoS tab to configure Quality of Service (QoS) settings on the switch. 
The QoS tab contains links to the following features:
339 
In a typical switch, each physical port consists of one or more queues for transmitting 
packets on the attached network. Multiple queues per port are often provided to give 
preference to certain packets over others based on user-defined criteria. When a packet is 
queued for transmission in a port, the rate at which it is serviced depends on how the queue 
is configured and possibly the amount of traffic present in the other queues of the port. If a 
delay is necessary, packets get held in the queue until the scheduler authorizes the queue for 
transmission. As queues become full, packets have no place to be held for transmission and 
get dropped by the switch.
QoS is a means of providing consistent, predictable data delivery by distinguishing between 
packets that have strict timing requirements from those that are more tolerant of delay. 
Packets with strict timing requirements are given “special treatment” in a QoS-capable 
network. With this in mind, all elements of the network must be QoS-capable. The presence 
of at least one node which is not QoS-capable creates a deficiency in the network path and 
the performance of the entire packet flow is compromised.
Class of Service
The Class of Service (CoS) queueing feature lets you directly configure certain aspects of 
switch queueing. This provides the desired QoS behavior for different types of network traffic 
when the complexities of DiffServ are not required. The priority of a packet arriving at an 
interface can be used to steer the packet to the appropriate outbound CoS queue through a 
mapping table. CoS queue characteristics that affect queue mapping, such as minimum 
guaranteed bandwidth, or transmission rate shaping are user-configurable at the queue (or 
port) level.
Eight queues per port are supported.