Cisco 642-437 Questions And Answers, Up To Date Cisco 642-437 Dump On Sale

Welcome to download the newest Flydumps MB6-700 VCE dumps: http://www.flydumps.com/MB6-700.html

Important Info — Cisco 642-437 new study guide are designed to help you pass the exam in a short time.Everything you need can be found in the new version Cisco 642-437 exam dumps.Visit Flydumps.com to get more valid information.

QUESTION: 1
The show policy-map interface command output is showing too many random drops for the mission-critical traffic class. What can be changed to reduce the random drops?
A. Increase the WRED max-threshold value for the mission-critical traffic class.
B. Increase the WRED min-threshold value for the mission-critical traffic class.
C. Decrease the WRED drop probability denominator for the mission-critical traffic class.
D. Decrease the queue-limit for the mission-critical traffic class.
E. Enable fair-queue within the mission-critical traffic class.
Answer: B
Explanation:
Weighted Fair Queuing (WFQ) is a dynamic process that divides bandwidth among queues based on weights. The process is designed to be fair, such that WFQ ensures that all traffic is treated fairly, with regard to its weight. There are several forms of WFQ, including Class-based Weighted Fair Queuing (CBWFQ) and Low Latency Queuing (LLQ). CBWFQ is probably the form of WFQ that is most commonly being deployed these days. CBWFQ works quite a bit like CQ, but the algorithm is more efficient and the configuration is quite a bit easier to understand. With CBWFQ, classes are created and traffic is assigned to those classes, as explained earlier in this chapter. Bandwidth is then assigned to those classes, and the amount of bandwidth assigned to a given class determines the amount of scheduling that class receives. In other words, the bandwidth statement on a given class determines the minimum amount of bandwidth that packets belonging to that class receive in the event of congestion. In the recent past, a PQ was added to the CBWFQ mechanism, specifically to handle VoIP traffic. This addition was necessary because, although CBWFQ did an excellent job of dividing up the available bandwidth, CBWFQ did not give any specific regard to the delay or jitter being introduced by queuing packets. The LLQ mechanism is CBWFQ with a single PQ, which receives strict scheduling priority. To go back to airline analogies, this is the equivalent of preboarding courtesies that are often offered to persons with special needs or those traveling with small children. In spite of the fact that these people may not be in first class, or elite frequent fliers, they are moved directly to the front of the line and put on the plane first because they have special needs. In the case of VoIP traffic, it may not be the most important traffic on your network, but it has very specific requirements for delay and jitter and, therefore, must be moved to the front of the line for transmission. Catalyst switches use classification to appropriate queuing frames for transmission. Although Catalyst switches only support the Cisco IOS features WFQ, CBWFQ, and LLQ on WAN interfaces, Ethernet interfaces use similar forms of queuing but vary in configuration and behavior.

QUESTION: 2
For which service is assured forwarding PHB used?
A. Best effort
B. Expedited forwarding
C. Guaranteed bandwidth
D. Class selector
Answer: C

Explanation:
With the introduction of the DSCP markings, there were significantly more possible markings for packets (0-63 are the possible markings for packets). Because there were so many more possible markings, the IETF decided to standardize what some of the codepoints meant. In part, this is to provide backward compatibility to IP precedence and, in part, this is to facilitate certain types of behaviors that were seen as fundamental to the DiffServ architecture. The following definition of a per-hop behavior is taken from Section 2.4 of RFC 2475: A per-hop behavior (PHB) is a description of the externally observable forwarding behavior of a DS node applied to a particular DS behavior aggregate … In general, the observable behavior of a PHB may depend on certain constraints on the traffic characteristics of the associated behavior aggregate, or the characteristics of other behavior aggregates. RFC 2597: The Assured Forwarding PHB Other than those defined in RFC 2474, there are two main PHBs, RFC 2597 defines the first of these. It is called the assured forwarding (AF) PHB, and the concept behind the PHB is to provide a level of assurance as to a given packet’s probability of being forwarded during congestion. RFC 2597 defines four classes, and each class is completely independent of the other classes. In addition, each class has three level of “drop precedence” to which packets of that class can be assigned.
QUESTION: 3
What are the two queuing options to the Catalyst 2950? (Choose two)
A. IP3Q
B. 2P2Q
C. 4Q
D. 1P2QIT

Answer: A, C

QUESTION: 4
What is the class selector PHB used for in the differentiated services model?
A. Best-effort service
B. Low-delay service
C. Bandwidth guarantee
D. Backward compatibility
Answer: D

Explanation:
With the introduction of the DSCP markings, there were significantly more possible markings for packets (0-63 are the possible markings for packets). Because there were so many more possible markings, the IETF decided to standardize what some of the codepoints meant. In part, this is to provide backward compatibility to IP precedence and, in part, this is to facilitate certain types of behaviors that were seen as fundamental to the DiffServ architecture. The following definition of a per-hop behavior is taken from Section 2.4 of RFC 2475: A per-hop behavior (PHB) is a description of the externally observable forwarding behavior of a DS node applied to a particular DS behavior aggregate … In general, the observable behavior of a PHB may depend on certain constraints on the traffic characteristics of the associated behavior aggregate, or the characteristics of other behavior aggregates. RFC 2597: The Assured Forwarding PHB Other than those defined in RFC 2474, there are two main PHBs, RFC 2597 defines the first of these. It is called the assured forwarding (AF) PHB, and the concept behind the PHB is to provide a level of assurance as to a given packet’s probability of being forwarded during congestion. RFC 2597 defines four classes, and each class is completely independent of the other classes. In addition, each class has three level of “drop precedence” to which packets of that class can be assigned.
QUESTION: 5
DRAG DROP
Match the IOS QoS feature on the left to the appropriate QoS mechanism on the right.

Answer:
Explanation:
A protocol-dependent switching process handles traffic arriving at a router interface. The switching process includes delivery of traffic to an outgoing interface buffer. First-in, first-out (FIFO) queuing is the classic algorithm for packet transmission. With FIFO, transmission occurs in the same order as messages are received. Until recently, FIFO queuing was the default for all router interfaces. If users require traffic to be reordered, the department or company must establish a queuing policy other than FIFO queuing. Cisco IOS software offers three alternative queuing options:
1.
Weighted fair queuing (WFQ) prioritizes interactive traffic over file transfers in order to ensure satisfactory response time for common user applications.

2.
Class-based weighted fair queuing (CBWFQ) in IOS 12.2 prioritizes traffic based on user-defined classes.

3.
Low latency queuing (LLQ) (IOS 12.2) brings strict priority queueing to Class-Based Weighted Fair Queuing (CBWFQ).
QUESTION: 6
Which other protocol does the auto qos voip cisco-phone command require to operate between the switch port and the IP phone?
A. RTP

B. Skinny Protocol
C. CDP
D. RTCP
E. VTP
F. DTP
Answer: C

Explanation:
Through the use of dot1q trunks, voice traffic from an IP Phone connected to an access port can reside on a separate VLAN and subnet. The workstation attached to the IP Phone might still reside on the access, or native, VLAN. This additional VLAN on an access port for voice traffic is referred to as a voice VLAN in Cisco IOS Software and auxiliary VLAN in CatOS. Subsequently, with the use of voice VLANs, all voice traffic is tagged to and from the Cisco IP Phone and Catalyst switch. The Catalyst switches use Cisco Discovery Protocol (CDP) to inform the IP Phone of the voice VLAN ID. By default, Cisco IP Phone voice traffic has a CoS value of 5. Here an example logical depiction of a voice VLAN. A common network design is to deploy both voice VLANs with trusting configurations for Cisco IP telephony applications (such as Cisco IP Phones). Another QoS option for IP Phones is extended trust. The switch can inform the IP Phone via CDP whether to trust ingress frames on its P1 port. The IP Phone may also be informed to overwrite the CoS value of the ingress frames on the P1 port with a specific CoS value. By default, the IP Phone does not trust frames arriving on the P1 port and rewrites the CoS value to 0 of any tagged frames. Untagged frames do not have CoS value. Extended trust is a feature available to any device that can interpret the CDP fields describing the voice VLAN information. At the time of publication, Cisco IP Phones and other Cisco appliances are the only devices to use this feature.
QUESTION: 7
What are the four types of per-hop behavior used with DSCP? (Choose four)
A. Expedited forwarding
B. Default
C. Class-bit
D. Assured forwarding
E. Class-selector
F. Express forwarding
Answer: A, B, D, E
Explanation:

With the introduction of the DSCP markings, there were significantly more possible markings for packets (0-63 are the possible markings for packets). Because there were so many more possible markings, the IETF decided to standardize what some of the codepoints meant. In part, this is to provide backward compatibility to IP precedence and, in part, this is to facilitate certain types of behaviors that were seen as fundamental to the DiffServ architecture. The following definition of a per-hop behavior is taken from Section 2.4 of RFC 2475: A per-hop behavior (PHB) is a description of the externally observable forwarding behavior of a DS node applied to a particular DS behavior aggregate … In general, the observable behavior of a PHB may depend on certain constraints on the traffic characteristics of the associated behavior aggregate, or the characteristics of other behavior aggregates. RFC 2597: The Assured Forwarding PHB Other than those defined in RFC 2474, there are two main PHBs, RFC 2597 defines the first of these. It is called the assured forwarding (AF) PHB, and the concept behind the PHB is to provide a level of assurance as to a given packet’s probability of being forwarded during congestion. RFC 2597 defines four classes, and each class is completely independent of the other classes. In addition, each class has three level of “drop precedence” to which packets of that class can be assigned. Expedited Forwarding (EF) PHB:
-Ensures minimum departure rate
-Guarantees bandwidth : The class is guaranteed an amount of bandwidth with prioritized forwarding
– Policies bandwidth : The class is not allowed to exceed the guaranteed amount
-Packets requiring Expedited Forwarding should be marked with DSCP binary Value.
QUESTION: 8
Which four of the following are required to calculate the LLQ priority bandwidth requirement for the voice traffic class? (Choose three)
A. Codec type
B. IP/UDP/RTP header lengths and Layer 2 overhead.
C. IP Phone Skinny Protocol overhead.
D. Number of concurrent VoIP calls to support.
E. Voice digitalization overhead.
Answer: A, B, D

Explanation:
The Low Latency Queuing (LLQ) feature provides strict priority queuing for class-based weighted fair queuing (CBWFQ), reducing jitter in voice conversations. Configured by the priority command, strict priority queuing gives delay-sensitive data, such as voice, preferential treatment over other traffic. With this feature, delay-sensitive data is sent first, before packets in other queues are treated. LLQ is also referred to as priority queuing/class-based weighted fair queuing (PQ/CBWFQ) because it is a combination of the two techniques. For CBWFQ, the weight for a packet belonging to a specific class is derived from the bandwidth assigned to the class during configuration. Therefore, the bandwidth assigned to the packets of a class determines the order in which packets are sent. All packets are serviced equally, based on weight. No class of packets may be granted strict priority. This scheme poses problems for voice and video traffic that is largely intolerant of delay, especially variation in delay. For voice traffic, variations in delay introduce irregularities of transmission, which manifest as jitter in the conversation. To enqueue a class of traffic to the strict priority queue, configure the priority command for the class after specifying the class within a policy map.
The Flydumps New Cisco 642-437 practice tests helps the user to keep a check on their learning and understanding and improve for the Cisco 642-437 exam. Flydumps makes you pass your exam much easier.

Flydumps MB6-700 dumps with PDF + Premium VCE + VCE Simulator: http://www.flydumps.com/MB6-700.html