2.1 QoS control architecture

Along with best-effort traffic that does not require guaranteed communications quality, the growing diversification of network services has meant an increase in real-time and guaranteed bandwidth traffic. You can use QoS control on the Switch to provide communications quality appropriate for the type of traffic.

QoS control on the Switch ensures the efficient use of limited network resources, such as line bandwidth and queue buffer capacity. To satisfy the many types of communications quality required for applications, use QoS control to distribute network resources in the most appropriate manner.

The following figure shows the functional blocks for QoS control on the Switch.

Figure 2-1 Function block for QoS control of this equipment

The following table provides an overview of the functional blocks shown in the figure.

Table 2-1 Outline of each function block of QoS control

Section and functional blocks		Overview of authentication VLAN functionality
Receive processing section	Frame reception	A frame is received.
Common processing section	User priority mapping	Determines priority based on the user priority in the VLAN tag of received frames.
Flow control section	Flow detection	Detects a frame that matches a condition, such as MAC address, protocol type, IP address, TCP/UDP port number, or ICMP header.
	Marking	Updates the user priority in the DSCP or VLAN tag in the IP header.
	Priority determination	Determines the priority of frames and the queuing priority, which indicates how easily a frame can be discarded.
Send control section	Drop control	Controls whether frames can be queued or dropped according to the packet priority and queue status.
	Shaper	Controls the output order of frames from queues and the output bandwidth.
Send processing section	Frame sending	Sends frames controlled by the shaper.

QoS control on the Switch uses user priority mapping or flow control to determine the priority of received frames. User priority mapping determines the priority based on the user priority in the VLAN tag of a received frame. You can use flow control to determine the priority based on whether the frame matches a specific condition, such as the MAC address or IP address, rather than based on the user priority.

The priority determined by flow control has priority over user priority mapping. Flow control can also enforce markers in addition to priority determination. Marker and priority determination functions can operate simultaneously for flows detected by flow detection.

Send control performs drop control and uses the shaper based on the priority determined by user priority mapping or flow control.