3.3.3 Notes on using bandwidth monitoring

<Structure of this section>

(1) Use bandwidth monitoring on VLAN interfaces

In some models and stacked configurations, there are combinations of ports that can be used when bandwidth monitoring is performed on VLAN interfaces. The following table lists the available port combinations. Do not use bandwidth monitoring for combinations that are not applicable.

Table 3-8: Available port combinations
Model	Configuration
Model	Standalone	Stack
AX2630S-48T4XW AX2630S-48P4XW	Port 1~24,49~50, Or Port 25~48,51~54 Combination of	Within one member switch, Port 1~24,49~50, Or Port 25~48,51~54 Combination of
All other cases	No limit	Within a single member switch

(2) Relationship between Bandwidth Monitoring, Transmit Ethernet Interface, and Transmit Queue

In the following cases, compliance frames may be discarded on the transmit Ethernet interface or the transmit queue:

When the monitoring bandwidth value specified in bandwidth monitoring is set to a value greater than the bandwidth value of the transmit Ethernet interface or transmit queue of the applicable flow
When a flow that does not use bandwidth monitoring and a flow that uses bandwidth monitoring are sent to the same transmit Ethernet interface or transmit queue

In particular, when using multiple bandwidth monitoring for multiple flows, pay attention to the sum of the monitored bandwidth values for each bandwidth monitoring.

(3) Using Maximum Bandwidth Control for TCP Frames

When the maximum bandwidth control is used, TCP slow start is repeated and the data-transfer rate may become extremely slow.

To prevent the above operation, use minimum bandwidth monitoring to perform the "Decrease the queuing priority so that frames are easily discarded" operation. This setting ensures that frames that exceed the contracted bandwidth will not be discarded immediately, but will be discarded only when the output line is congested.

(4) Simultaneous operation with other functions

If a frame is received from a port specified by the port-to-port forwarding blocking functionality, the frame is discarded, but the frame is subject to bandwidth monitoring.