monitoring process. Cisco AutoQoS provides visibility into the classes of service deployed via system logging and Simple Network Management Protocol (SNMP) traps, with notification of abnormal events (for example, VoIP packet drops). Once AutoQoS is turned on, SNMP traps generated by Cisco AutoQoS are delivered only if an SNMP server is explicitly enabled and the community string "AutoQoS" is given write permission. In the case of low-speed Frame Relay/ATM and serial links, Cisco AutoQoS must be enabled on both ends of the connection to function correctly. Also, because the fragmentation parameters are derived from the bandwidth, the bandwidth parameter on both ends of the link must be identical. The show auto qos output displays the information that Remote Monitoring (RMON) traps logging voice packet drops is enabled. This output is used for monitoring and troubleshooting. AutoQoS activates thresholds in the RMON alarm table to monitor drops in LLQ. By default, the drop threshold is set to 1 bps. Figure shows an example of an alarm event triggered by dropped packets. In some situations, as shown in the output for Frame Relay, Cisco AutoQoS also projects new traffic parameters. In Figure , Cisco AutoQoS generated the new Frame Relay map class, which is mapped to the specific DLCI using the invented map class name. Finally, the show auto qos output displays how the QoS policy was applied in the configuration. In this case, the service policy was applied to the new Frame Relay map class, which in turn was mapped to the DLCI. In addition to the contents of the interface configurations, you can also display policy maps and class maps using the show auto qos command. Access control lists (ACLs) are also displayed if Cisco AutoQoS generated them.

---

Content 5.2 Mitigating Common Cisco AutoQoS Issues 5.2.6 Modifying the Active Cisco AutoQoS Configuration with MQC If the policy maps and class maps created based on the templates generated by Cisco AutoQoS for the Enterprise do not meet the needs of the enterprise network, use the appropriate Cisco IOS commands to make the necessary changes. This issue usually occurs in two situations:

• The new Cisco AutoQoS generated configuration does not meet specific enterprise expectations.
• Network or traffic conditions have changed while Cisco AutoQoS generated the configuration, and network administrators have the necessary skills to adapt the existing QoS configuration rather than running the entire Cisco AutoQoS deployment procedure again.

Figure provides a decision map to assist you in deciding whether you need to make manual modifications. Caution
Although you can modify the policy maps and class maps, they may not be removed properly when Cisco AutoQoS for the Enterprise is disabled using the no auto qos command. You may have to remove any modified policy maps and class maps manually. Modifying the Active Cisco AutoQoS Configuration with MQC: Classification
Most commonly, Cisco AutoQoS uses NBAR and ACLs for traffic classification. However, any Cisco MQC classification mechanism can supplement or replace the configuration generated by Cisco AutoQoS. Significant skills and MQC knowledge are required to perform the modification, but this procedure can adapt the classification to even the most complex classification rules. Classification can be modified either after the Cisco AutoQoS discovery but before the generated policy templates are applied or after the policy templates generated by Cisco AutoQoS are applied. There are several ways to tune and modify the existing class maps:

• Directly at the router command-line interface (CLI) using MQC
• Using Cisco QoS Policy Manager (QPM)

However, the easiest way to tune the existing class maps is to copy them into a text editor and modify the configuration offline. Add the desired new classification and remove the undesired existing classification. When the modification is complete, copy the new classification from the editor and paste it to a router configuration prompt to push the rules through the built-in parser of the router. Figure summarizes these points with an example. If required, you can repeat the tuning procedure in an iterative process until you achieve the optimal configuration. Cisco MQC offers a broad range of classification options, to use when adding to the class map rules generated by Cisco AutoQoS. Figure summarizes these points and the table lists the most common classification options and their respective match commands. Besides these classification options, any classification supported by Cisco MQC can be used in any combination to meet specific classification requirements. Example: Classification Tuning Using the MQC
The following is an example of classification tuning using the MQC:

1. Start the Cisco AutoQoS discovery process.
   Router#configure terminal
   Router(config)#interface serial0/1/0
   Router(config-if)#bandwidth 384
   Router(config-if)#auto discovery qos
   Router(config-if)#end


2. Leave the Cisco AutoQoS discovery running for several days.
   
3. Review the Cisco AutoQoS discovery results and identify classification changes required (only the classification portion is shown).
   Router#show auto discovery qos
   <output omitted>
   !
   Suggested AutoQoS Policy for the current uptime:
   class-map match-any AutoQoS-Voice-Se0/1/0
   match protocol rtp audio
   !
   class-map match-any AutoQoS-Signaling-Se0/1/0
   match protocol h323
   !
   class-map match-any AutoQoS-Transactional-Se0/1/0
   match protocol sqlnet
   match protocol citrix
   !
   class-map match-any AutoQoS-Bulk-Se0/1/0
   match protocol exchange
   match protocol ftp
   !
   class-map match-any AutoQoS-Scavenger-Se0/1/0
   match protocol kazaa2
   !
   class-map match-any AutoQoS-Management-Se0/1/0
   match protocol ldap Necessary classification changes include these: Step 1 Also, classify Session Initiation Protocol (SIP) and Media Gateway Control Protocol (MGCP) signaling. Step 2 Classify Telnet traffic as Transactional class. Step 3 Move the SQL classification from the Transactional class to the Bulk class. Step 4 Classify all SNMP traffic coming from the IP subnet 193.87.95.0 as Management class.

1. Apply the generated Cisco AutoQoS policy template to the interface for later modification.
   Router#configure terminal
   Router(config)#interface serial0/1/0
   Router(config-if)#auto qos
   Router(config-if)#end


2. Modify the classification generated by Cisco AutoQoS according to the requirements.
   Step 1 Also, classify SIP and MGCP signaling.
   Router#configure terminal
   Router(config)#class-map AutoQoS-Signaling-Se0/1/0
   Router(config-cmap)#match protocol sip
   Router(config-cmap)#match protocol mgcp
   Router(config-cmap)#exit Step 2 Classify Telnet traffic as Transactional.
   Router(config)#class-map AutoQoS-Transactional-Se0/1/0
   Router(config-cmap)#match protocol telnet
   Router(config-cmap)#exit Step 3 Move the SQL classification from the Transactional class to the Bulk class.
   Router(config)#class-map AutoQoS-Transactional-Se0/1/0
   Router(config-cmap)#no match protocol sqlnet
   Router(config-cmap)#exit