Exam Topics The following topics are general guidelines for the content likely to be included on the exam. However, other related topics may also appear on any specific delivery of the exam. In order to better reflect the contents of the exam and for clarity purposes, the guidelines below may change at any time without notice. 642-642 QoS Exam Topics Describe the need to implement QoS on a converged network Identify problems that could lead to poor quality of service on a converged network Explain how the poor quality of service problems might be resolved Explain the methods for implementing QoS on a converged network with Cisco's routers and Catalyst Switches Describe and explain the legacy Cisco's IOS methods for implementing QoS Describe and explain the Cisco's MQC method for implementing QoS Describe and explain Cisco's AutoQoS method for implementing QoS Identify and describe different models used for ensuring QoS in a network Describe and explain the best effort model Describe and explain the IntServ QoS model Describe and explain the DiffServ QoS model Explain the key IP QoS mechanisms used to implement the DiffServ QoS model Describe and explain the operations of the QoS classifications and marking mechanisms Describe and explain the operations of the QoS congestion avoidance mechanisms Describe and explain the operations of the QoS congestion management mechanisms Describe and explain the operations of the QoS traffic conditioning mechanisms 1
Describe and explain the operations of the QoS WAN Link Efficiency mechanisms Explain and Configure AutoQoS on Cisco's routers Explain and configure the auto qos command on Cisco's routers to automatically enable QoS mechanisms Explain and Configure AutoQoS on Cisco's Catalyst Switches Explain and configure the auto qos command on Cisco's IOS based Catalyst Switches to automatically enable QoS mechanisms Explain and configure the set port qos autoqos command on Cisco's CAT based Catalyst Switches to automatically enable QoS mechanisms Configure QoS mechanisms using the Cisco's MQC method Explain and configure class-maps including nested class-maps Explain and configure policy-maps including hierarhical policy-maps Explain how a policy-map is applied to an interface using the service-policy command Configure NBAR protocol discovery and classification Configure NBAR protocol discovery on Cisco's routers Configure NBAR traffic classification using the match protocol command Enable NBAR SNMP notifications on Cisco's routers Explain the need for PDLM and the IOS command to specify the location of the PDLM file to extend the NBAR capabilities on Cisco's routers. Configure class-based markings Describe and explain the different layer 2 and layer 3 QoS markers (CoS, MPLS EXP, FR DE, ATM CLP, DSCP, IPP) Explain the need to map layer 2 QoS marking into layer 3 QoS marking Explain the different DSCP values (AF1x, AF2x, AF3x, EF, BE) Explain the different IPP values (IPP 0 to IPP 7) Explain the different set option within a policy-map (including set dscp, set ip precedence, set cos) Explain what is the trust boundary 2
Configure the QoS Pre-Classify feature Explain the QoS pre-classify feature to support QoS over GRE and IPSec tunnels Configure QoS pre-classify on GRE and IPSec tunnels Configure the QPPB classification and marking feature Explain and configure QPPB on Cisco's routers Configure LLQ and CBWFQ on Cisco's routers Explain and configure CBWFQ on Cisco's routers Explain and configure LLQ on Cisco's routers Configure QoS Trust Boundary on Cisco's Catalyst 2950 switches Explain the function of the internal DSCP value on Cisco's Catalyst Switches Explain and configure trust boundry on Cisco's Catalyst Switches (trust cos, trust dscp, trust cos passthru dscp) Explain and Configure CoS-to-DSCP and DSCP-to-CoS mappings on Cisco's Catalyst 2950 switches Configure PQ and WRR queuing on Cisco's Catalyst 2950 switches Explain and Configure PQ on Cisco's Catalyst 2950 switches Explain and Configure WRR queuing on Cisco's Catalyst 2950 switches Explain and Configure WRR queuing with an Expedited Queue on Cisco's Catalyst 2950 switches Configure CBWRED on Cisco's routers Explain and Configure IPP based CBWRED on Cisco's routers Explain and Configure DSCP based CBWRED on Cisco's routers Explain and Configure DSCP based CBWRED with ECN on Cisco's routers Configure CB traffic shaping on Cisco's routers Explain and configure average and peak rate class-based traffic shaping 3
Explain and configure average and peak rate class-based traffic shaping on FR PVCs Explain and configure adaptive class-based traffic shaping on FR PVCs Configure CB traffic policing on Cisco's routers Explain and configure single and dual token bucket class-based traffic policing Explain and configure dual rate class-based traffic policing Explain and configure multi-actions class-based traffic policing Configure LFI on PPP serial interface on Cisco's routers Explain and configure multilink PPP with interleaving on Cisco's routers Configure LFI on Frame Relay PVCs on Cisco's routers Explain and configure FRTS/FRF.12 over Frame Relay PVCs on Cisco's routers Configure CB Header Compression on Cisco's routers Configure CB TCP Header Compression on Cisco's routers Configure CB RTP Header Compression on Cisco's routers Explain Cisco's traffic classifications and markings best practice recommendations Explain the general principles for data traffic classifications Identify the Cisco's best practice markings for the routing, voice, video conferencing, streaming video, mission-critical data, call-signaling, transactional data, network management data, bulk data, scavenger data, and best effort data. Explain Cisco's Campus QoS best practice recommendations Explain the typical voice traffic latency, jitter and packer loss requirements Explain the typical video conferencing traffic latency, jitter and packer loss requirements Explain the typical video streaming traffic latency, jitter and packer loss requirements Explain the typical required QoS configurations at the Campus access layer switch, distribution layer switch and the core layer switch 4
Explain Cisco's WAN Edge QoS best practice recommendations Explain the difference between the two types of SLA (point-to-point SLA and point-to-cloud SLA) Explain the typical QoS configurations at the WAN Edge routers (The CE-PE link) Explain the differences with the typical QoS configurations at the CE and PE router using unmanaged vs managed CE service Explain Cisco's Network Core QoS best practice recommendations Explain the benefits of using a DiffServ backbone vs. a Best Effort with over-provisioning backbone Explain the typical QoS configurations at the P routers using a DiffServ backbone Troubleshoot and verify QoS configuration and operations on Cisco's routers and Catalyst Switches Use various show and debug commands to troubleshoot and verify proper router's MQC QoS configurations and operations Verify and provide statistics on the traffic running on the network using NBAR protocol discovery show commands Use various show and debug commands to troubleshoot and verify proper autoqos configurations Use various show and debug commands to troubleshoot and verify proper QPPB operations Use various show and debug commands to troubleshoot and verify proper QoS Pre-Classify operations Use various show and debug commands to troubleshoot and verify proper FRF.12 operations Use various show and debug commands to troubleshoot and verify proper Multiplink PPP with Interleaving operations Use various show commands to troubleshoot and verify proper trust boundry operations on Cisco's Catalyst 2950 switches Use various show commands to troubleshoot and verify proper COS-DSCP mapping on the Catalyst 2950 switches Use various show commands to troubleshoot and verify proper PQ, WRR, WRR with an Expedite Queue operations on Cisco's Catalyst 2950 switches 5