H3C S5120-EI series Configuration Manual

Also see for S5120-EI Series: Configuration guide Installation manual Configuration guide Configuration guide Operation manual

Contents

H3C S5120-EI series Configuration Manual Manual pdf 34 page image

24Applying the QoS policy to a VLANYou can apply a QoS policy to a VLAN to regulate traffic of the VLAN.QoS policies cannot be applied to dynamic VLANs, such as VLANs created by GVRP.To apply the QoS policy to a VLAN:Step Command Remarks1. Enter system view. system-view N/A2. Apply the QoS policy toVLANs.qos vlan-policy policy-name vlanvlan-id-list inbound N/AApplying the QoS policy globallyYou can apply a QoS policy globally to the inbound direction of all ports.To apply the QoS policy globally:Step Command Remarks1. Enter system view. system-view N/A2. Apply the QoS policyglobally.qos apply policy policy-nameglobal inbound N/AApplying the QoS policy to the control planeA device provides the data plane and the control plane.• The data plane has units responsible for receiving, transmitting, and switching (forwarding) packets,such as various dedicated forwarding chips. They deliver super processing speeds and throughput.• The control plane has processing units running most routing and switching protocols andresponsible for protocol packet resolution and calculation, such as CPUs. Compared with dataplane units, the control plane units allow for great packet processing flexibility, but have lowerthroughput.When the data plane receives packets that it cannot recognize or process, it transmits them to the controlplane. If the transmission rate exceeds the processing capability of the control plane, which very likelyoccurs at times of DoS attacks, the control plane will be busy handling undesired packets and fail tohandle legitimate packets correctly or timely. As a result, protocol performance is affected.To address this problem, apply a QoS policy to the control plane to take QoS actions, such as trafficfiltering or rate limiting, on inbound traffic. This action ensures that the control plane can receive, transmit,and process packets properly.Configuration restrictions and guidelines• By default, devices are configured with pre-defined control plane policies, which take effect on thecontrol planes by default. A pre-defined control plane QoS policy uses the system-index to identifythe type of packets sent to the control plane. You can reference system-indexes in if-matchcommands in class view for traffic classification and then re-configure traffic behaviors for theseclasses as required. You can use the display qos policy control-plane pre-defined command todisplay them.