Download New Latest (May) Cisco 642-887 Actual Tests 41-50

Ensurepass

 

QUESTION 41

Which three network services can be implemented using MPLS within the service provider IP NGN core? (Choose three.)

 

A.

Layer 2 VPNs

B.

Layer 3 VPNs

C.

traffic engineering

D.

IntServ traffic engineering tunnels

E.

encrypted LSPs

 

Answer: ABC

 

 

QUESTION 42

Scenario:

 

 

 

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On P2IOS-XR router what is targeted LDP hellos hold time on LDP session with 10.0.1.1:0 LDP ID?

 

A.

90 sec

B.

10 sec

C.

3 sec

D.

8.6 sec

 

Answer: A

Explanation: Issue on P2: show mpls ldp discovery (details).

Ps: The command show mpls ldp parameter is not Implemented. Look at the end, you will see the hello and the holdtime values for the target neighbour. Be careful he is asking for “targeted LDP hellos hold time”. No other command will work!!! At the end of the show result you will see something looks like the following:

 

LDP discovery sources:

 

Targeted Hello 10.0.2.1 -> 10.0.1.1 active, passive; Hello: 30 sec

holdtime: 90 sec

 

 

QUESTION 43

A DSCP value of 41 in decimal corresponds to which IP precedence value?

 

A.

3 ?Flash

B.

4 ?Flash Override

C.

5 ?Critical

D.

6 ?Internet Control

E.

7 ?Network Control

 

Answer: C

Explanation:= INT(41/8)

The AF behavior group defines four separate AF classes with Class 4 having the highest priority. Within each class, packets are give
n a drop precedence (high, medium or low). The combination of classes and drop precedence yields twelve separate DSCP encodings from AF11 through AF43 (see table)

 

 

 

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QUESTION 44

Which QoS mechanism is used for congestion avoidance?

 

A.

LLQ

B.

CBWFQ

C.

WRED

D.< /span>

LFI

E.

traffic policing

 

Answer: C

 

 

QUESTION 45

In Cisco MPLS TE implementations, what can cause the tunnel bandwidth to adjust automatically based on the traffic load in the tunnel?

 

A.

fast reroute

B.

admin weight

C.

autobandwidth

D.

bandwidth subpool

 

Answer: C

 

 

QUESTION 46

When configuring LLQ (strict priority queue) on a traffic class using the Cisco IOS XR priority command on a Cisco ASR9K router, which additional QoS command is required for this traffic class?

 

A.

shape

B.

police

C.

random-detect

D.

bandwidth

 

Answer: B

Explanation:The Low Latency Queueing feature brings strict priority queueing to Class-Based Weighted Fair Queueing (CBWFQ).

 

 

QUESTION 47

In which two Cisco IOS XR configuration modes can mpls ldp igp sync be configured? (Choose two.)

 

A.

config-ldp

B.

config-if

C.

config-ospf-ar

D.

config-ospf

E.

config-isis

 

Answer: CD

 

 

QUESTION 48

Implementing IPoDWDM interfaces on Cisco CRS routers eliminates the need for which network component?

 

A.

ROADM

B.

external transponders

C.

electrical-optical-electrical converters

D.

electrical cross-connect

 

Answer: B

Explanation:IP over DWDM (IPoDWDM) is a technology used in telecommunications networks to integrate IP Routers and Switches in the OTN (Optical Transport Network).

 

 

QUESTION 49

Which affinity value will be matched by the affinity bit mask of the affinity 0xFF00000A mask 0xFFFF000F command?

 

A.

0xFFFF000A

B.

0xFF00EEEA

C.

0xFF000000

D.

0x00000000

E.

0x11110001

 

Answer: B

Explanation:0xFF00000A 11111111000000000000000000001010

0xFFFF000F 11111111111111110000000000001111

0xFF00EEEA 11111111000000001110111011101010

 

 

QUESTION 50

The Cisco IOS and IOS XE qos pre-classify command allows which kind of packet classification on IP packets that are encapsulated with GRE and IPsec?

 

A.

allows for packets to be classified based on the ToS byte values before packet encryption

B.

allows for packets to be classified based on the ToS byte values after packet encryption

C.

allows for packets to be classified based on the packet payload before packet encryption

D.

allows for packets to be classified based on the packet payload after packet encryption

E.

allows for packets to be classified based on the packet header parameters other than the ToS byte values after packet encryption

 

Answer: A

Explanation:http://www.cisco.com/en/US/tech/tk543/tk545/technologies_tech_note09186a008017405e.

shtml

The qos pre-classify command When packets are encapsulated by tunnel or encryption headers, QoS features are unable to examine the original packet headers and correctly classify the packets. Packets traveling across the same tunnel have the same tunnel headers, so the packets are treated identically if the physical interface is congested. With the introduction of the Quality of Service for Virtual Private Networks (VPNs) feature, packets can now be classified before tunneling and encryption occur. In this example, tunnel0 is the tunnel name. The qos pre-classify command enables the QoS for VPNs feature on tunnel0:

Router(config)# interface tunnel0

Router(config-if)# qos pre-classify

 

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