Cisco Certified Voice Professional

The CCVP certification recognizes the increased importance placed on IT professionals of today who are responsible for integrating voice technology into underlying network architectures. Individuals who earn a CCVP certification can help create a telephony solution that is transparent, scalable, and manageable. Earning a CCVP certification validates a robust set of skills in implementing, operating, configuring, and troubleshooting a converged IP network. The certification content focuses on Cisco Systems CallManager, quality of service (QoS), gateways, gatekeepers, IP phones, voice applications, and utilities on Cisco routers and Cisco Catalyst switches.

642-642 QoS

The QOS exam is one of the qualifying exams for the Cisco Certified Internetwork Professional, Cisco Certified Voice Professional, Cisco IP Telephony Design Specialist, Cisco IP Telephony Express Specialist, Cisco IP Telephony Operations Specialist, and Cisco IP Telephony Support Specialist certifications. The QOS 642-642 exam will test materials covered under the Implementing Cisco Quality of Service QOS v2.1 course. The exam will certify that the successful candidate has knowledge and skills necessary to configure and troubleshoot Cisco IOS routers running Quality of Service protocols in Service Provider and Enterprise environments. The exam covers topics on IP QOS, classification and marking Mechanisms, queuing mechanisms, traffic shaping and policing mechanisms, congestion avoidance mechanisms, link efficiency mechanisms, modular QOS command line interface, and QOS Best Practices.

Exam Topics

The following information provides 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.

IP QoS Fundamentals

IP QoS Components

• List and explain the models for providing Quality of Service on a network
• Explain the purpose and function of the DiffServ model
• Describe the basic format of and explain the purpose of the DSCP field in the IP header
• Define and explain the different per hop behaviors used in DSCP
• Explain the interoperability between DSCP-based and IP-precedence-based devices in a network
• Given a list of QoS actions, correctly match the QoS actions to mechanisms for implementing QoS and identify where in a network the different QoS mechanisms are commonly used

Modular QoS CLI and Auto-QoS

• Given a network requiring QoS, explain how to implement a QoS policy using MQC
• Explain how AutoQoS is used to implement QoS policy

Classification and Marking

• Explain how link layer and network layer markings are used to define service classes and the different applications represented by each of these service classes
• Given a network and a description of QoS issues, use MQC CLI commands to classify packets
• Given a network and a description of QoS issues, use class-based marking to assign packets to a specific service class
• Describe the function of Network Based Application Recognition
• Describe the purpose of pre-classification to support QoS in various VPN (IPSEC, GRE, L2TP) configurations
• Describe QoS trust boundaries and their significance in LAN based classification and marking
• Identify the different classification and marking options available on Cisco L2 and L3 switching platforms

Congestion Management Methods

• List and explain the different queuing algorithms
• Explain the components of hardware and software queuing systems on Cisco routers and how they are effected by tuning and congestion
• Describe the benefits and drawbacks of using WFQ to implement QoS
• Explain the purpose and features of Class-Based WFQ (CBWFQ)
• Explain the purpose and features of Low Latency Queuing (LLQ)
• Identify the Cisco IOS commands required to configure and monitor LLQ on a Cisco router
• Describe and explain the different queuing capabilities available on the Cisco Catalyst 2950 Switch

Congestion Avoidance Methods

• Describe the drawbacks tail drop as a congestion control mechanism
• Describe the elements of a RED traffic profile
• Describe Weighted Random Early Detection and how it can be used to prevent congestion
• Identify the Cisco IOS commands required to configure and monitor DSCP-based CB-WRED
• Explain how ECN interacts with WRED in Cisco IOS

Traffic Policing and Shaping

• Describe the purpose of traffic conditioning using traffic policing and traffic shaping and differentiate between the features of each
• Explain how network devices measure traffic rates using single rate or dual rate, single or dual token bucket mathematical models
• Identify the Cisco IOS commands required to configure and monitor single rate and dual rate CB-Policing
• Identify the Cisco IOS commands required to configure and monitor percentage based CB-Policing
• Explain how the two rate limits, average rate and peak rate, can be used to rate limit traffic
• Identify the Cisco IOS commands required to configure and monitor CB-Shaping
• Identify the Cisco IOS commands required to configure and monitor Frame Relay adaptive CB-Shaping on Frame Relay interfaces

Link Efficiency Mechanisms

• Explain the various link efficiency mechanisms and their function
• Identify the Cisco IOS commands required to configure and monitor CB header compression
• Given a list of link speeds and a specific delay requirement, determine the proper fragment size to use at each link speed and identify the typical delay requirement for VoIP packets
• Identify the Cisco IOS commands required to configure and monitor Multilink PPP with Interleaving
• Identify the Cisco IOS commands required to configure and monitor FRF.12

QoS Best Practices

• Explain the QoS requirements of the different application types
• List typical enterprise traffic classes then identify the delay, jitter, packet loss and bandwidth requirements of each traffic class
• Explain the best practice QoS implementations and configurations within the campus LAN
• Explain the best practice QoS implementations and configurations on the WAN customer edge (CE) and provider edge (PE) routers