Renew 642-889 Prep 2021

NEW QUESTION 1
What is the primary difference between 6PE and 6VPE?

• A. 6VPE does not require an MPLS core.


• B. 6VPE requires an IPv6-aware core.


• C. 6VPE provides IPv6 VPN services.


• D. 6VPE tunnels IPv6 packets inside IPv4 packets.

Answer: C

Explanation:
6PE is for transporting ipv6 natively and 6VPE is for ipv6 mpls vpns

NEW QUESTION 2
Which two statements about implementing a separate MPLS VPN to provide customers Internet access are correct? {Choose two.}

• A. The Internet gateway router will act as a CE router.


• B. Customers will use separate interfaces for VPN and Internet access.


• C. Customers are assigned to the Internet VPN.


• D. Internet routes will be leaked from the PE global routing table to the customer VRF.

Answer: AC

NEW QUESTION 3
Refer to the partial Cisco IOS XR PE router configuration exhibit for supporting a Layer 3 MPLS VPN customer using EIGRP AS 20 as the CE-to-PE routing protocol.

The MPLS VPN customer is having problems receiving the EIGRP routes on the different customer site CE routers.
What is wrong with this configuration that is causing the problem?

• A. The router eigrp command is referencing the wrong AS number.


• B. The redistribute eigrp command is missing the metric transparent option.


• C. The redistribute eigrp command is referencing the wrong AS number.


• D. The redistribute bgp command is missing the subnets option.


• E. The redistribute eigrp command is missing the subnets option.

Answer: C

NEW QUESTION 4
When you are using OSPF as the CE-to-PE routing protocol in MPLS VPN implementations, an OSPF route from customerA site 1 in Area 0 will appear as which kind of OSPF route in customerA site 2, also in Area 0?

• A. intra-area


• B. interarea


• C. E1


• D. E2

Answer: B

NEW QUESTION 5
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.

NEW QUESTION 6
A customer requests Internet through its MPLS provider. Which Internet design model guarantees maximum security and easier provisioning?

• A. Internet access through global routing


• B. Internet access through route leaking


• C. Internet access through a separate VPN service


• D. Internet access through multisite

Answer: C

NEW QUESTION 7
Which option is the correct command to define an interface as Layer 2 on the Cisco ASR 9000?

• A. RP/0/RSP0/CPU0:R1{config}#int gigabitEthernet 0/6/0/0 l2transport


• B. RP/0/RSP0/CPU0:R1{config}#int gigabitEthernet 0/6/0/0 layer2


• C. RP/0/RSP0/CPU0:R1{config}#int gigabitEthernet 0/6/0/0 switchport


• D. RP/0/RSP0/CPU0:R1{config}#int gigabitEthernet 0/6/0/0 xconnect

Answer: A

Explanation:

NEW QUESTION 8
Refer the exhibit.




On PE7, how many multiprotocol IBGP routes are learned from PE8 and what is the next-hop IP address? {Choose two.}

• A. 1


• B. 2


• C. 3


• D. 10.8.1.1


• E. 172.16.8.1


• F. 192.168.108.81

Answer: BE

Explanation:
Show ip bgp vpnv4 all --- i tag field is the answer

NEW QUESTION 9
Refer to the exhibit.

PE1 and PE2 are advertising the same subnet 10.10.10.0/24 to PE3. Which PE advertised subnet is installed at the PE3 XYZ BGP table?

• A. PE2 subnet because it has the same RD value as PE3


• B. PE2 subnet because it has the same export RT value as export RT on PE3


• C. PE1 subnet because it has the same RD value as PE3


• D. PE1 subnet because it has the same export RT value as import RT on PE3

Answer: D

NEW QUESTION 10
Which two options are disadvantages of MPLS Layer 3 VPNs? {Choose two.}

• A. IP-only support


• B. lack of scalability


• C. dependency on service provider Layer 3 model


• D. complex PE-CE configuration


• E. less efficient than hub-and-spoke model

Answer: AD

NEW QUESTION 11
A customer is connecting to a Cisco IOS XR PE device via BGP. The peering session is up and the customer is advertising routes, but the provider is not receiving any. Which issue is the most likely cause?

• A. The IOS XR device drops inbound routing updates on eBGP peers without an inbound route-policy.


• B. The IOS XR device requires as-override on all eBGP customer peers.


• C. The IOS XR device requires labeled-unicast peering sessions to eBGP customers.


• D. The IOS XR device drops inbound routing updates on eBGP peers that do not send extended communities.

Answer: A

NEW QUESTION 12
Refer the exhibit.




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

NEW QUESTION 13
In which Cisco IOS XR configuration mode is the redistribute static command applied to enable the redistribution of static VRF routes between the PE routers?

• A. RP/0/RP0/CPU0:PE{config-router}#


• B. RP/0/RP0/CPU0:PE{config-bgp}#


• C. RP/0/RP0/CPU0:PE{config-bgp-vrf}#


• D. RP/0/RP0/CPU0:PE{config-bgp-vrf-af}#

Answer: D

Explanation:
http://www.cisco.com/en/US/docs/routers/asr9000/software/routing/configuration/guide/rcasr9kstat.html#wp1041 359

NEW QUESTION 14
Which VPN technology is an example of a full-mesh VPN?

• A. VTI


• B. GRE VPN


• C. Frame Relay L2 VPN


• D. MPLS L3VPN

Answer: D

NEW QUESTION 15
A network engineer is troubleshooting an MPLS Layer 3 VPN and discovers that routes are being learned by CE routers, but there is no IP connectivity. Which option is the most likely cause?

• A. The provider does not have an end-to-end label switch path.


• B. The customer does not have an end-to-end label switch path.


• C. The customer is not sharing labels with the provider.


• D. The provider is not sharing labels with the customer.


• E. The providers PE to CE routing protocol is misconfigured.


• F. The customers PE to CE routing protocol is misconfigured.

Answer: A

NEW QUESTION 16
When troubleshooting EoMPLS configuration problems, which three parameters must match between the two ends of the pseudowire configurations? {Choose three.}

• A. control word usage


• B. MTU size


• C. pseudowire ID


• D. Xconnect group name


• E. EFP subinterface number

Answer: ABC

Explanation:
Provisioning an AToM Static Pseudowire
In this configuration task, you use options in the xconnect Ethernet interface configuration command to specify a static connection, and mpls commands in xconnect mode to statically set the following pseudowire parameters:
•Set the local and remote pseudowire labels
•Enable or disable sending the MPLS control word


Haven't been able to find where MTU Must match

NEW QUESTION 17
Which option describes what differentiates a U-PE from N-PE?

• A. U-PE has all BGP routes from different BGP AFIs.


• B. N-PE has VRF configured and exported via BGP.


• C. U-PE is configured to peer BGP with all other BGP neighbors.


• D. N-PE is used to physically connect customer edge routers.

Answer: A

NEW QUESTION 18
Which two Layer 2 VPN methods support interworking between customer sites with different Layer 2 encapsulation at each end {for example, Frame Relay to Ethernet interworking}? {Choose two.}

• A. AToM


• B. VPLS


• C. GET VPN


• D. L2TPv3

Answer: AD

Explanation:
http://www.cisco.com/en/US/docs/ios/12_3t/12_3t2/feature/guide/gtl2tpv3.html#wp1040784
The Layer 2 Tunnel Protocol Version 3 feature expands on Cisco support of the Layer 2 Tunnel Protocol Version 3 {L2TPv3}. L2TPv3 is an Internet Engineering Task Force {IETF} l2tpext working group draft that provides several enhancements to L2TP for the capability to tunnel any Layer 2 payload over L2TP.
Specifically, L2TPv3 defines the L2TP protocol for tunneling Layer 2 payloads over an IP core network using Layer 2 virtual private networks {VPNs}. Benefits of this feature include the following:
•L2TPv3 simplifies deployment of VPNs
•L2TPv3 does not require Multiprotocol Label Switching
•L2TPv3 supports Layer 2 tunneling over IP for any payload http://www.cisco.com/en/US/products/ps6646/products_ios_protocol_option_home.html
Cisco Any Transport over MPLS {AToM} is a solution for transporting Layer 2 packets over an MPLS backbone. It enables Service Providers to supply connectivity between customer sites with existing data link layer {Layer 2} networks via a single, integrated, packet-based network infrastructure: a Cisco MPLS network. Without separate networks that each have network management environments, Service Providers can deliver Layer 2 connections over an MPLS backbone.
Cisco AToM provides a common framework to encapsulate and transport supported Layer 2 traffic types over an MPLS network core. Service Providers can use a single MPLS network infrastructure to offer connectivity for supported Layer 2 traffic and for IP traffic in Layer 3 VPNs.

NEW QUESTION 19
Which VPN technology allows remote sites with dynamic IP addresses to connect to a central hub?

• A. static IPsec tunnels


• B. site-to-site VPN


• C. DMPVN


• D. VRFs

Answer: C

NEW QUESTION 20
Which two statements regarding Cisco 6PE operations are correct? {Choose two.}

• A. The top label in the label stack is assigned by MP-BGP, and it is used to reach the egress PE.


• B. The inner label in the label stack is assigned by MP-BGP, and it is used for IPv6 forwarding at the egress PE.


• C. The top label in the label stack is assigned by LDP, and it is used to reach the egress PE.


• D. The inner label in the label stack is assigned by LDP, and it is used for IPv6 forwarding at the egress PE.

Answer: BC

Explanation:
http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6553/prod_presentation0900aecd80311df4.pdf

NEW QUESTION 21
What is the purpose of the route distinguisher in a service provider network?

• A. to identify which prefixes should be imported


• B. to identify customer local prefixes


• C. to identify customer global prefixes


• D. to identify which prefixes should be exported from BGP

Answer: C

NEW QUESTION 22
In Layer 3 MPLS VPN implementations, if a customer is using the same AS number at both customer sites and the PE- to-CE routing protocol is BGP, what must be enabled on the PE router?

• A. BGP AS override


• B. BGP allowas-in


• C. BGP SOO extended community


• D. BGP AS path prepending

Answer: A

Explanation:
https://supportforums.cisco.com/docs/DOC-21837
Loop prevention in BGP is done by verifying the AS number in the AS Path. If the receiving router sees its own AS number in the AS Path of the received BGP packet, the packet is dropped. The receiving Router assumes that the packet was originated from its own AS and has reached the same place from where it originated initially.
The feature could be a disaster if customers are using same AS number along the various sites and disallows customer sites having identical AS numbers to be linked by another AS number. In such a scenario, routing updates from one site will be dropped when the other site receives them.
To override this feature, AS-Override function causes to replace the AS number of originating router with the AS number of the sending BGP router. The command is neighbor ip-address as-override and can only be executed under the VPNv4 address-family

NEW QUESTION 23
Refer to the exhibit.

XR2 must be configured with a static route for 2.2.2.0/24 subnet toward CE2 into the VRF ABC table. Which configuration achieves this goal?

• A. router static vrf ABC2.2.2.0/24 10.10.24.2


• B. router static vrf ABC2.2.2.0/24 10.10.24.2address-family ipv4 unicast


• C. router static vrf ABCaddress-family ipv4 unicast 2.2.2.0/24 10.10.24.2


• D. router staticaddress-family ipv4 unicast vrf ABC2.2.2.0/24 10.10.24.2

Answer: C

NEW QUESTION 24
Which two MPLS QoS models described by RFC3270 are used for CE-PE QoS implementation? {Choose two.}

• A. best effort


• B. pipe


• C. uniform


• D. integrated services


• E. differentiated services

Answer: BC

NEW QUESTION 25
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