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: Functional blocking of QoS control of the Device

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

Table 2-1 Summary of QoS Control Function Blocks

Section and functional blocks		Overview of authentication VLAN functionality
Receive processing section	Frame reception	Receives frames and searches the MAC address table and routing table.
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.
	Bandwidth monitoring	Monitors the bandwidth of frame flow and assigns a penalty to frames that exceed the bandwidth.
	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. You can also use flow control to employ bandwidth monitoring and marking in addition to priority determination. Bandwidth monitoring, marking, and priority determination can operate concurrently for the frames 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.

Notes

Keep the following in mind when using the QoS control.

• When packet processing performance is exceeded in AX3660S-48XT4QW,AX3660S-24X4QW, and AX3660S-48X4QW, packets may be discarded regardless of the flow-detection setting.

• Flow control or send control cannot be set on a stack port.