3-9
QoS policies cannot be applied to dynamic VLANs, for example, VLANs created by GVRP.
Applying the QoS policy globally
You can apply a QoS policy globally to the inbound or outbound direction of all ports.
Follow these steps to apply the QoS policy globally:
To do…
Use the command…
Remarks
Enter system view
system-view
—
Apply the QoS policy globally
qos apply policy
policy-name
global
{
inbound
|
outbound
}
Required
A QoS policy containing any of the
nest
,
remark customer-vlan-id
, and
remark service-vlan-id
Actions cannot be applied globally.
Applying the QoS policy to the control plane
Packet processing units fit into the data plane and the control plane depending on their functions.
z
At the data plane are units responsible for receiving, transmitting, and switching (that is,
forwarding) packets, such as various dedicated forwarding chips. They deliver super processing
speeds and throughput.
z
At the control plane are processing units running most routing and switching protocols and
responsible for protocol packet resolution and calculation, such as CPUs. Compared with data
plane units, they allow for great packet processing flexibility but have lower throughput.
When the data plane receives packets that it cannot recognize or process, it transmits them to the
control plane. If the transmission rate exceeds the processing capability of the control plane, which
very likely occurs at times of DoS attacks, the control plane will be busy handling undesired packets
and fail to handle legitimate packets correctly or timely. As a result, protocol performance is affected.
To address this problem, you can apply a QoS policy to the control plane to take QoS actions such as
traffic filtering or rate limiting on inbound traffic, thus ensuring that the control plane can receive,
transmit, and process packets normally.
Follow these steps to apply the QoS policy to the control plane:
To do…
Use the command…
Remarks
Enter system view
system-view
—
Enter control plane view (on a
distributed device)
control-plane slot slot-number
Required
