Cisco Systems 7401ASR No Buffers, Priority and Policing Configured in the Class Policy, PXF Punts

Chapter 5 Troubleshooting

PXF Troubleshooting Information

No Buffers

If there are too many buffers configured for the output hold queue on an interface, this can use memory and result in dropped input packets. Enter the show running-configcommand and the show interfaces command to display the status of the incoming packet interfaces.

Priority and Policing Configured in the Class Policy

PXF does not support a configured priority and policing in the same class of a policy.

PXF Punts

If a feature that is supported in the PXF path appears not to be working, it could be the result of PXF failing to punt packets when it should. If you have only particular interfaces running the feature, you can configure a feature that PXF does not support on that interface to force PXF to punt packets.

QoS Fast-send and QoS Enqueue

PXF is responsible for managing the outbound traffic queues on an interface on which output QoS queueing is configured. All traffic destined for this interface must be processed by PXF, including both keepalive packets that originate in the router, known as QoS Fast-send packets, and packets that are switched in IOS, known as QoS Enqueue packets. If there is excessive traffic on the QoS Enqueue or on the QoS Fast-send path, QoS functionality can be disrupted. Use the show pxf accounting summary command to display the QoS Fast-send and QoS Enqueue packets:

Router# show pxf accounting summary

.
.
.
qos fastsend:	8
qos enqueue:	5

WFQ Queues

When there is an increase in ignored packets and in the no buffer count, it is possible that the output weighted fair queueing (WFQ) queues are too long. To specify the number of dynamic queues to be reserved for use by the class-default class as part of the default class policy, use the fair-queuepolicy-map class configuration command; for example:

Router# fair-queue

policy-map policy9 class class-default fair-queue 16 queue-limit 20

	Cisco 7401ASR Installation and Configuration Guide
5-10	OL-5419-01 B0