KYLAND Technology SICOM3024P, Web Operation Manual

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Advanced Configuration
101
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Enable RSTP transparent transmission on ports A1, A2, A3, B1, B2, B3, C1, C2, D1, and
D2, as shown in Figure 98.
6.15 QoS
6.15.1 Overview
Quality of Service (QoS) enables differentiated services based on different requirements
under limited bandwidths by means of traffic control and resource allocation on IP networks.
QoS tries to satisfy the transmission of different services to reduce network congestion and
minimize congestion's impact on the services of high priority.
QoS mainly involves service identification, congestion management, and congestion
avoidance.
Service identification: Objects are identified based on certain match rules. For example, the
objects can be priority tags carried by packets, priority mapped by ports and VLANs, or
priority information mapped by quintuples. Service identification is the precondition for QoS.
Congestion management: This is mandatory for solving resource competition. Congestion
management caches packets in queues and determines the sequence of packet forwarding
based on a certain scheduling algorithm, achieving preferential forwarding for key services.
Congestion avoidance: Excessive congestion may result in damage on network resources.
Congestion avoidance monitors the use of network resources. When detecting increasing
congestion, the function adopts proactive packet discarding and tunes traffic volume to solve
the overload.
6.15.2 Principle
Each port of the switch has four cache queues, from 0 to 3 in priority ascending order.
You can configure the mapping between priority and queues. When a frame reaches the port,
the switch determines the queue for the frame according to the information in the frame
header. The switch supports five queue mapping modes for priority identification: highest
priority, port-based, DIFF, TOS/DIFF, and 802.1p.
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If the highest priority is configured on a port, then packets to be forwarded are put in