Approved 642-889 Paper 2021

NEW QUESTION 1
When implementing a Layer 2 transport subinterface on a Cisco IOS XR router, which encapsulation option is used to match any packets that are not matched by any other service instances?

• A. default
• B. untagged
• C. any
• D. tag

Answer: A

Explanation:

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
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 4
DRAG DROP

• A. Mastered
• B. Not Mastered

Answer: A

Explanation:
Business subscribers are an important segment of many service providers' customer base. The main business services that must be provided by the network today are:
• MPLS VPN
• Carrier Ethernet connectivity
• Managed services
Carrier Ethernet connectivity services have been defined by the Metro Ethernet Forum {MEF} to include ELine, E-LAN, and E-Tree service types, which are defined as follows:
• E-Line is based on a point-to-point Ethernet Virtual Connection. Two E-Line services are defined:
- Ethernet Private Line {EPL}: A very simple and basic point-to-point service characterized by low frame delay, frame delay variation, and frame loss ratio. No service multiplexing is allowed, and other than a committed information rate {CIR} no class of service {CoS} {Bandwidth Profiling} is allowed.
- Ethernet Virtual Private Line {EVPL}: A point-to-point service wherein service multiplexing {more than one Ethernet Virtual Connection} is allowed. The individual Ethernet Virtual Circuits can be defined with a rich set of Bandwidth Profiles and Layer 2 Control Protocol Processing methods as defined by the Metro Ethernet Forum.
• E-LAN is based on a multipoint-to-multipoint Ethernet Virtual Connection. Service multiplexing {more than one Ethernet Virtual Circuit at the same UNI} is permitted, as is the rich set of performance assurances defined by the MEF such as CIR with an associated Committed Burst Size {CBS} and Excess Information Rate {EIR}.
• E-Tree is a point-to-multipoint ELAN service in which the spoke "leaves" can communicate with the hub or "root" location but not with each other. Typical application for E-Tree is in franchise operations.

NEW QUESTION 5
In Layer 3 MPLS VPN implementations, which protocol is used to carry the VPNv4 routes from PE to PE?

• A. RSVP
• B. IGP
• C. MP-BGP
• D. LDP

Answer: C

NEW QUESTION 6
An engineer is deploying L2VPN service between two different Layer 2 encapsulations. Which feature should be set up to accomplish this task?

• A. interworking VLAN on both the provider edge routers
• B. interworking Ethernet on both the provider edge routers with VLAN tagging
• C. interworking IPv4 on both the customer edge routers
• D. interworking IPv4 on both the provider edge routers

Answer: D

NEW QUESTION 7
A customer has two sites over an MPLS cloud with Ethernet connections and requires one STP domain to be transparent over the MPLS provider. Which label-switching technology can the provider use without getting involved in learning the customer MAC addresses?

• A. L2TPV3
• B. EoMPLS
• C. VPLS
• D. H-VPLS

Answer: B

NEW QUESTION 8
Which three functions are performed by the PE router in an MPLS Layer 3 VPN? {Choose three.}

• A. exchanges routing updates with the CE router
• B. translates the CE routing information into VPNv4 routes
• C. exchanges VPNv4 routes with other PE routers over MP-BGP
• D. imports and exports RTs that are received from the P routers
• E. exchanges RDs with the P routers
• F. exchanges VPN labels with the CE routers

Answer: ABC

Explanation:
http://www.cisco.com/en/US/docs/routers/crs/software/crs_r4.1/lxvpn/configuration/guide/vc41v3.html How MPLS L3VPN Works
MPLS VPN functionality is enabled at the edge of an MPLS network. The PE router performs the following tasks:
•Exchanges routing updates with the CE router
•Translates the CE routing information into VPN version 4 {VPNv4} and VPN version 6 {VPNv6} routes
•Exchanges VPNv4 and VPNv6 routes with other PE routers through the Multiprotocol Border Gateway Protocol {MP- BGP}

NEW QUESTION 9
In MPLS Layer 3 VPN implementations, what is used at the PEs to transform the customer IPv4 prefixes into a unique 96-bit prefix?

• A. RT
• B. RD
• C. VC ID
• D. PW ID
• E. AS number

Answer: B

NEW QUESTION 10
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 11
When configuring VPLS on the Cisco ASR 9000, which three configurations are required under the l2vpn configuration mode? {Choose three.}

• A. bridge-group
• B. bridge-domain
• C. xconnect
• D. vfi
• E. encapsulation

Answer: ABD

Explanation:

NEW QUESTION 12
Refer to the Cisco IOS XR router output exhibit,

which method is being used to transport IPv6 traffic over the service provider network?

• A. 6PE
• B. 6VPE
• C. native IPv6
• D. native IPv4
• E. dual stack

Answer: B

Explanation:
NOT SURE THIS MATCHES ANSWER

NEW QUESTION 13
Which three possible misconfigurations can occur on the backbone IGP section of an MPLS Layer 3 VPN setup? {Choose three.}

• A. configuring the LDP router ID with an incorrect loopback interface
• B. configuring the wrong AS number on a client eBGP peering
• C. configuring the wrong area number on a PE-CE OSPF link
• D. decreasing the MPLS MTU
• E. disabling MPLS on a core link
• F. disabling MPLS LDP sync in the IGP routing process

Answer: ADE

NEW QUESTION 14
A PE configured with VRF ABC needs to export only subnet 1.1.1.1/32 with RT 100:100 without losing its original RT 200:200 to a remote PE. Which configuration is correct?
A}
B}
C}
D}

• A. Exhibit A
• B. Exhibit B
• C. Exhibit C
• D. Exhibit D

Answer: C

NEW QUESTION 15
Which Layer 2 encapsulations can AToM solution support with interworking IP feature enable?

• A. Ethernet to ATM AAL5
• B. ATM AAL5 to Frame Relay
• C. PPP to Frame Relay
• D. multipoint PPP to Frame Relay

Answer: A

NEW QUESTION 16
Which three options are features of MPLS Layer 2 VPNs? {Choose three.}

• A. Routing occurs on customer devices.
• B. Routing occurs on service provider and customer devices.
• C. Customer sites appear to be on the same LAN.
• D. Customer sites appear to be on different LANs in the same routing domain.
• E. A routing protocol must be configured between the CE and PE device.
• F. Traffic between CE and PE is forwarded in Layer 2 format.

Answer: ACF

NEW QUESTION 17
Which two methods can be used for VPLS PW signaling? {Choose two.}

• A. static
• B. BGP
• C. IGP
• D. LDP
• E. RSVP

Answer: BD

Explanation:

NEW QUESTION 18
Which method can be used to discover targeted LDP neighbors dynamically when configuring VPLS between PE routers?

• A. BGP autodiscovery
• B. VPLS peers under the VFI
• C. VPWS
• D. BGP

Answer: A

NEW QUESTION 19
Which VPN technology uses the Group Domain of Interpretation as the keying protocol and IPsec for encryption that is often deployed over a private MPLS core network?

• A. DMVPN
• B. GET VPN
• C. SSL VPN
• D. L2TPv3

Answer: B

Explanation:
http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6586/ps6635/ps7180/deployment_guide_c07_554 713.html

NEW QUESTION 20
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 21
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