642-889 Actual Tests (May)

Download New Latest (May) Cisco 642-889 Actual Tests 41-50

May 17, 2015

Ensurepass

 

QUESTION 41

The Cisco IOS XR address-family ipv4 labeled-unicast and the Cisco IOS/IOS XE neighbor send-label commands are used in which MPLS implementation?

 

A.

Cisco MPLS TE

B.

CSC using MP-BGP for label exchange

C.

back-to-back VRF

D.

AToM

E.

VPLS

 

Answer: B

Explanation:

http://www.cisco.com/en/US/docs/ios/12_0s/feature/guide/fscscleb.pdf

 

The MPLS VPN–Carrier Supporting Carrier–IPv4 BGP Label Distribution feature lets you configure your carrier-supporting-carrier network to enable Border Gateway Protocol (BGP) to transport routes and Multiprotocol Label Switching (MPLS) labels between the backbone carrier provider edge (PE) routers and the customer carrier customer edge (CE) routers using multiple paths. Previously, you had to use Label Distribution Protocol (LDP) to carry the labels and an Internal Gateway Protocol (IGP) to carry the routes between PE and CE routers to achieve the same goal.

 

The benefits of using BGP to distribute IPv4 routes and MPLS label routes are:

?BGP takes the place of an IGP and LDP in a Virtual Private Network (VPN) forwarding/routing instance (VRF) table. You can use BGP to distribute routes and MPLS labels. Using a single protocol instead of two simplifies the configuration and troubleshooting.

?BGP is the preferred routing protocol for connecting two Internet service providers (ISPs), mainly because of its routing policies and ability to scale. ISPs commonly use BGP between two providers.

 

This feature enables those ISPs to use BGP.

 

 

QUESTION 42

On Cisco IOS XR platforms using the EVC infrastructure, which command is used to enable a Layer 2 VPN subinterface?

 

A.

interface gi0/0/0/0.10

switchport access vlan 10

B.

interface gi0/0/0/0.10

switchport mode tunnel dot1q-tunnel

C.

interface gi0/0/0/0.10

switchport mode trunk

D.

interface gi0/0/0/0.10

bridge-group 10

E.

interface gi0/0/0/0.10 l2transport

 

Answer: E

Explanation:

 

 

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C:\Documents and Settings\user-nwz\Desktop\1.JPG

 

 

QUESTION 43

In MPLS Layer 3 VPN implementations, which mechanism is used to control which routes are imported to a VRF?

 

A.

RT

B.

RD

C.

VC ID

D.

PW ID

E.

VRF ID

 

Answer: A

Explanation:http://blog.initialdraft.com/archives/1537/

 

 

QUESTION 44

Which CE-to-PE routing protocol implements the down bit as a loop prevention mechanism?

 

A.

RIPv2

B.

EIGRP

C.

IS-IS

D.

OSPF

E.

BGP

 

Answer: D

Explanation:https://www.racf.bnl.gov/Facility/TechnologyMeeting/Archive/06-30-04-CISCO/Using- OSPF-in-MPLS-VPNEnvironment.pdf

 

 

 

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C:\Documents and Settings\user-nwz\Desktop\1.JPG

 

 

QUESTION 45

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On PE7, which encapsulation method is used on the pseudowire that connects to the 10.8.1.1 neighbor?

 

A.

MPLS

B.

L2TPv3

C.

IP

D.

LDP

E.

Ethernet

 

Answer: B

Explanation:show xconnect all

check value is mpls or l2tp or Ethernet etc in segment field

 

 

QUESTION 46

When implementing EoMPLS on Cisco IOS XR routers, which command under the l2vpn configuration mode is used to define the pseudowire?

 

A.

pbb

B.

xconnect

C.

connect

D.

bridge

E.

bridge-domain

 

Answer: B

Explanation:http://www.cisco.com/en/US/docs/wireless/asr_901/Configuration/Guide/eompls.html

 

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C:\Documents and Settings\user-nwz\Desktop\1.JPG

 

 

QUESTION 47

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What type of routing is used between CE7 and PE7?

 

A.

OSPF

B.

BGP

C.

is-is

D.

RIPv2

E.

Static routing

 

Answer: E

Explanation:# show ip route

 

 

QUESTION 48

On Cisco IOS and IOS XE Layer 3 MPLS VPN implementations, when redistributing the customer RIP routes into MP-BGP, the RIP metric is copied into which BGP attribute?

 

A.

local preference

B.

weight

C.

MED

D.

extended community

 

Answer: C

Explanation:https://supportforums.cisco.com/thread/191993

Use the red bgp <asn> metric transparent command to preserve the RIP metrics. When RIP routes are redistributed into BGP, the route metric is stored in the BGP MED value. When BGP routes are redistributed into RIP, and the transparent keyword used, the MED value is copied back as the RIP metric. Without the transparent keyword, the metric value specified is applied to all the routes.

 

 

QUESTION 49

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On PE7, which three statements are correct regarding the MPLS VPN configurations used to support the connectivity between the CE7 and CE8 sites? (Choose three.)

 

A.

The RD is 1:1

B.

The import and export RTs are 1:1

C.

Interface GiO/0/0/0 is associated to the “default” VRF

D.

The network that connects PE7to CE7 is redistributed into multiprotocol IBGP

E.

The multiprotocol IBGP routes learned have a BGP origin code of “i”

 

Answer: BCE

Explanation:# show ip route

show ip vrf

show ip vrf detail

 

 

QUESTION 50

In Layer 3 MPLS VPN implementations, if some of the VPNv4 routes on one PE router do not appear on another PE router, what could be the problem?

 

A.

RD mismatch between the PE routers

B.

RT export and import configuration errors

C.

RD export and import configuration errors

D.

VRF name mismatch between the PE routers

 

Answer: B

Explanation:http://blog.initialdraft.com/archives/1537/

 

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