Configuring Traffic Shaping

Traffic shaping is similar to that of traffic policing. Traffic shaping buffers packets that need to be dropped by traffic policing by means of buffer and token bucket.

Usage Scenario

When the traffic volume on a network is heavy, nonconforming packets are directly discarded. If the upstream router sends a large volume of data traffic, the downstream network may be congested or a great number of packets are dropped. To prevent this situation, configure traffic shaping on the outbound interface of the upstream router to limit the traffic. Traffic shaping enables packets to be transmitted at an even rate and improves the allocation of bandwidth resources between the upstream and downstream networks.

Traffic shaping is carried out using buffers and token buckets. If packets are sent at a high rate, nonconforming packets are not dropped. Instead, such packets are placed in buffer queues. Under the control of token buckets, buffered packets are sent at an even rate by queue scheduling priority when the network is idle. As a result, packet retransmissions in case of packet dropping is prevented.

Differentiated service (DiffServ) is used to guarantee the bandwidth for behavior aggregate (BA) data traffic. The NetEngine 8000 F uses the queue scheduling mechanism to allocate resources to the services of different classes, such as expedited forwarding (EF) and assured forwarding (AF) queues. You do not need to configure queue management.

Currently, the NetEngine 8000 F supports traffic shaping only for the outgoing traffic on interfaces.

Pre-configuration Tasks

Before configuring traffic shaping, complete the following tasks:

Configure parameters for physical interfaces.
Configure link layer attributes for interfaces to ensure their normal operating.
Configure IP addresses for interfaces.
Enable a routing protocol for communication between devices.

Procedure

Configure interface-based traffic shaping.
1. Run system-view
  The system view is displayed.
2. Run interface interface-type interface-number
  The interface view is displayed.
3. Run port shaping { shaping-value | shaping-percentage shaping-percentage-value } [ pbs pbs-value ] [ weight-mode ]
  Traffic shaping is configured for outgoing traffic on the interface.
  
  To allocate shaping values based on the weight values of member interfaces, run the port shaping shaping-value [ weight-mode ] command.
4. Run port-queue cos-value { { pq | wfq weight weight-value | lpq } | shaping { shaping-value | shaping-percentage shaping-percentage-value } [ pbs pbs-value ] | port-wred wred-name | low-latency } ^* outbound
  A scheduling policy is configured for a specific PQ.
5. Run port-queue-alarm cos-value { discard-packet discard-packet-number | discard-byte discard-byte-number | discard-packet-ratio discard-packet-coefficient discard-packet-exponent } [ interval interval-time ]
  The packet loss alarm function for port queues is enabled.
6. Run commit
  The configuration is committed.
Configure traffic shaping based on a sub-interface queue.
1. Run system-view
  The system view is displayed.
2. Run sub-port-queue sub-port-queue-name
  The sub-interface queue profile view is displayed.
3. Run shaping shaping-value [ pbs pbs-value ] outbound
  A shaping value is configured for sub-interface queues.
  
  Run weight weight-value outbound
  
  A weight is configured for sub-interface queues.
4. Run quit
  Return to the system view.
5. Run interface interface-type interface-number
  The sub-interface view is displayed.
6. Run sub-port-queue sub-port-queue-name outbound [ group group-name ]
  The sub-interface queue profile is applied to the sub-interface.
7. Run commit
  The configuration is committed.
8. Run quit
  Return to the system view.
Configure traffic shaping in the slot view.
1. Run system-view
  The system view is displayed.
2. Run slot slot-id
  The slot view is displayed.
3. Run port shaping shaping-value bind mtunnel
  A peak rate is set at which the MTunnel interface in the distributed multicast VPN can send data.
4. Run commit
  The configuration is committed.

Verifying the Configuration

After you configure traffic shaping, check whether the configuration takes effect.

Run the display interface [ interface-type [ interface-number ] ] command to check traffic information on a specific interface.
Run the display service-template configuration [ verbose [ service-template-name ] ] command to check a user-defined service profile.
Run the display port-wred configuration [ verbose [ port-wred-name ] ] command to check the configuration of a port WRED object.
Run the display port-queue configuration interface interface-type interface-number outbound command to check the detailed PQ configuration.
Run the display port-queue statistics [ slot slot-id | interface interface-type interface-number ] [ cos-value ] outbound command to check PQ statistics.
Run the display port-queue statistics [ cos-value ] outbound command to check PQ statistics.