Hierarchical Queueing Framework

Hierarchical Queueing Framework (HQF)

Queueing
- Occurs when packets are delayed by router.
- Simplified in Ethernet Switches
  - Hardware Queues only
- Could be hierarchical
  - PVC-Queue (Frame-Relay)
    - Interface Queue (software queue)
      - Hareware queue (TX-Ring)
- Fancy queueing methods apply to software queue.
  - How traffic is processed when waiting for TxR

Modular Quality of Service Command line reference
- Allows multiple QoS methods per interface per direction.
  - Old QoS methods did not do this.
- Previously CBWFQ
- Now HQF
  - Hierarchical queueing framework
    - 12.4 and higher.

Configuration

Define traffic classes
- ‘class map’
- Define traffic match criteria
Define traffic policy
- ‘policy-map’
- Define actions
Apply Policy
- ‘service-policy [in/out]‘ on interface.

MQC Verification
- ‘show class-map’
- ‘show run class-map’
- ‘show policy-map’
- ‘show run policy-map’
- ‘show policy-map interface’

Define Traffic Classes w/ Class Map:

Class Map with a match statement

Policy Map:

The first statement we’re creating a policy map that will reference the class map we created.

Then the question mark shows all the options we have here for QoS mechanisms. Bandwidth is used for reserving a certain minimum amount of bandwidth for this type of flow. The flow can use more than what is set but if there’s high contention, then the flow will always have at least this minimum set.

In this scenario we will set a policer.

The Policer is set to 8000 bps. The conform action, ie. what to do when under 8000 bps, is set to transmit. The exceed-action, ie. what to do when over 8000 bps, is set to drop.

The last step is applying to an interface with the service-policy input command. Input or output means apply inbound or outbound on the interface.

Now on a neighboring router we’re going to send pings to this interface with a high repeat count. On the console of the neighboring router it shows that traffic is being stopped after a certain amount hits.