Table 9.9 is a quick reference guide to basic troubleshooting steps to try in the event of unsuccessful QoS deployment:
Table 9.9 Basic QoS Troubleshooting
Symptom
Suggested Remedy/Investigation
No connectivity
802.1p enabled on sender but not on receiver.
Non-802.1p—capable device between sender and receiver.
Failed traffic control installation; remove and reinstall QoS Packet Scheduler Service.
Registry entry MaxOutstandingSends in \Psched\Parameters set too low.
No discernible effect of QoS
End-to-end QoS signaling failure or traffic control failure. See "Troubleshooting Methodology" later in this chapter for assistance with tracing the source of the failure.
Network not congested.
No active QoS elements in those parts of the network that are congested.
Packets not tagged correctly with 802.1p.
Packets not marked correctly with DSCP.
QoS ACS policy ineffective
Policy configured in QoS ACS that is not the DSBM on the relevant segment (use the tool Wdsbm to find out which QoS ACS is the DSBM).
Verify that the QoS ACS is running under the account name of QoS ACSService . See Windows 2000 Server Help for procedural information.
RSVP messages dropped in the network
Router in path dropping RSVP messages. Use Rsping to verify integrity of RSVP path.
RSVP messages dropped due to congestion; verify 802.1p and DSCP marking for RSVP network control flow.
RSVP reservation requests rejected
Insufficient resources provisioned in intervening routers or QoS ACS.
Policy denial by QoS ACS.
Packets not tagged 802.1p
Traffic control not installed.
802.1p not enabled on interface.
QoS request denied for traffic flow.
Non-802.1p-capable interface.
Packets tagged with unexpected 802.1p tag
This is being overridden by a registry setting by the administrator.