Cisco 642-889 Free Practice Questions 2021

NEW QUESTION 1
Refer the exhibit.




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

NEW QUESTION 2
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/

NEW QUESTION 3
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 4
What is an advantage of using the Cisco EVC infrastructure to implement carrier-class Ethernet services that are not available on non-EVC-capable platforms?

• A. PW redundancy
• B. interworking support
• C. PW stitching support
• D. flexible frame-matching support and VLAN tag manipulation
• E. local cross-connect support

Answer: D

Explanation: http://www.cisco.com/web/YU/events/expo_08/pdfs/Carrier_Ethernet_Marek_Moskal.pdf

NEW QUESTION 5
Which three commands represent valid QoS classifiers of traffic in case of an EoMPLS circuit? {Choose three.}

• A. match cos
• B. match mpls experimental
• C. match qos-group
• D. match fr-de
• E. match protocol
• F. match ip address prefix-list
• G. match tag

Answer: ABC

NEW QUESTION 6
When implementing H-VPLS with QinQ access on Cisco Metro Ethernet switches, which two commands enable the QinQ tagging? {Choose two.}

• A. encapsulation dot1q {customer-vlan} second-tag {sp-vlan}
• B. encapsulation dot1q {sp-vlan} second-tag {customer-vlan}
• C. switchport mode dot1q-tunnel
• D. switchport mode trunk
• E. switchport access vlan {sp-vlan}
• F. switchport access vlan {customer-vlan}

Answer: CE

NEW QUESTION 7
DRAG DROP

Answer:

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 8
With Layer 3 MPLS VPN implementations on Cisco IOS XR PE routers, an interface is assigned to a VRF using the vrf command in which configuration mode?

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

Answer: B

Explanation:

NEW QUESTION 9
What is required on a Cisco IOS XR router to assign an interface to a VRF?

• A. Assign the VRF to the interface, and then re-enable Cisco Express Forwarding on the interface.
• B. Assign the VRF to the interface, and then reset the CE-to-PE routing protocol process.
• C. Shut the interface, assign the VRF to the interface, and then no shut the interface.
• D. Remove the IP address configuration on the interface, assign the VRF to the interface, and then reconfigure the IP address on the interface.

Answer: D

Explanation: http://www.cisco.com/en/US/docs/ios_xr_sw/iosxr_r3.5/mpls/configuration/guide/gc35v3.html#wp1080845

NEW QUESTION 10
Which option is the minimal configuration required inside the L2VPN section of a Cisco IOS XR PE router to activate VPLS functionality?

• A. l2vpnbridge group test bridge-domain testinterface TenGigE0/0/0/1.30!vfi testvpn-id 600 autodiscovery bgp rd 10.10.10.1:30route-target 1:300 signaling-protocol bgp ve-id 10
• B. l2vpnbridge group test bridge-domain testinterface TenGigE0/0/0/1.30!vfi testneighbor 10.10.10.2 pw-id 1400mpls static label local 1400 remote 1500
• C. l2vpnbridge group test bridge-domain testinterface TenGigE0/0/0/1.30!vfi testneighbor 10.10.10.2 pw-id 1400
• D. l2vpnbridge group test bridge-domain testinterface TenGigE0/0/0/1.30!vfi testvpn-id 600 autodiscovery bgp rd 10.10.10.1:30route-target 1:300 signaling-protocol bgp
• E. l2vpnbridge group test bridge-domain test vfi test autodiscovery bgp rd 10.10.10.1:30route-target 1:300 signaling-protocol bgp ve-id 10

Answer: C

NEW QUESTION 11
Which three Layer 3 VPN technologies are based on the overlay model? {Choose three.}

• A. ATM virtual circuits
• B. Frame Relay virtual circuits
• C. GRE/IPsec
• D. L2TPv3
• E. MPLS Layer 3 VPNs
• F. DMVPNs

Answer: CDF

Explanation: The overlay model, where the service provider provides emulated leased lines to the customer.
The service provider provides the customer with a set of emulated leased lines. These leased lines are called VCs, which can be either constantly available {PVCs} or established on demand {SVCs}. The QoS guarantees in the overlay VPN model usually are expressed in terms of bandwidth guaranteed on a certain VC {Committed Information Rate or CIR} and maximum bandwidth available on a certain VC {Peak Information Rate or PIR}. The committed bandwidth guarantee usually is provided through the statistical nature of the Layer 2 service but depends on the overbooking strategy of the service provider The peer-to-peer model, where the service provider and the customer exchange Layer 3 routing information and the provider relays the data between the customer sites on the optimum path between the sites and without the customer's involvement.
The peer-to-peer VPN model was introduced a few years ago to alleviate the drawbacks of the overlay VPN model. In the peer-to-peer model, the Provider Edge {PE} device is a router {PE-router} that directly exchanges routing information with the CPE router. The Managed Network service offered by many service providers, where the service provider also manages the CPE devices, is not relevant to this discussion because it's only a repackaging of another service. The Managed Network provider concurrently assumes the role of the VPN service provider providing the VPN infrastructure} and part of the VPN customer role {managing the CPE device}.
The peer-to-peer model provides a number of advantages over the traditional overlay model:
Routing {from the customer's perspective} becomes exceedingly simple, as the customer router exchanges routing information with only one {or a few} PE-router, whereas in the overlay VPN network, the number of neighbor routers can grow to a large number.
Routing between the customer sites is always optimal, as the provider routers know the customer's network topology and can thus establish optimum inter-site routing.
Bandwidth provisioning is simpler because the customer has to specify only the inbound and outbound bandwidths for each site {Committed Access Rate [CAR] and Committed Delivery Rate [CDR]} and not the exact site-to-site traffic profile.
The addition of a new site is simpler because the service provider provisions only an additional site and changes the configuration on the attached PE-router. Under the overlay VPN model, the service provider must provision a whole set of VCs leading from that site to other sites of the customer VPN.
Prior to an MPLS-based VPN implementation, two implementation options existed for the peer-to-peer VPN model: The shared-router approach, where several VPN customers share the same PE-router.
The dedicated-router approach, where each VPN customer has dedicated PE-routers.

NEW QUESTION 12
Which option is a valid Cisco IOS XR BGP Layer 3 IPv4 MPLS VPN configuration?

• A. router bgp 65001no bgp default ipv4-unicast bgp log-neighbor-changesneighbor 1.2.3.4 remote-as 65001 neighbor 1.2.3.4 update-source Loopback0 address-family vpnv4neighbor 1.2.3.4 activateneighbor 1.2.3.4 send-community extended exit-address-familyaddress-family ipv4 vrf VPN redistribute ospf 100
• B. router bgp 65001no bgp default ipv4-unicast bgp log-neighbor-changesneighbor 1.2.3.4 remote-as 65001 neighbor 1.2.3.4 update-source Loopback0 address-family vpnv4neighbor 1.2.3.4 activate exit-address-familyaddress-family ipv4 vrf VPN redistribute ospf 100
• C. router bgp 100address-family vpnv4 unicast neighbor 2.2.2.2remote-as 100update-source Loopback0 address-family vpnv4 unicast!vrf VPN_A rd 100:1address-family ipv4 unicast redistribute ospf 100
• D. router bgp 100address-family vpnv4 unicast neighbor 2.2.2.2remote-as 100update-source Loopback0 address-family ipv4 unicast!vrf VPN_A rd 100:1address-family ipv4 unicast redistribute ospf 100

Answer: C

NEW QUESTION 13
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 14
When configuring an EoMPLS PW on a Cisco IOS XR router, what are the two supported transport modes? {Choose two.}

• A. ethernet {Ethernet port mode}
• B. ip {routed mode}
• C. vlan {VLAN-tagged mode}
• D. transparent {bridged mode}

Answer: AC

Explanation: http://www.cisco.com/en/US/docs/ios_xr_sw/iosxr_r3.8/mpls/configuration/guide/gc38v2.html#wp1072883
•Ethernet Port Mode
•Ethernet Remote Port Shutdown
•VLAN Mode
•Inter-AS Mode
•QinQ Mode
•QinAny Mode
•Mac-in-Mac Protocol {Provide Backbone Bridging}

NEW QUESTION 15
When using the Cisco EVC software infrastructure, a double-tagged frame with a customer VLAN of 10 and a service provider VLAN of 150 will be best matched by which encapsulation configuration?

• A. encapsulation dot1q 10 second-dot1q any
• B. encapsulation dot1q 10 second-dot1q 150
• C. encapsulation dot1q 10 second-dot1q 50-200
• D. encapsulation dot1q 10
• E. encapsulation dot1q 150

Answer: E

NEW QUESTION 16
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 17
In which configuration mode is a route distinguisher configured in a Cisco IOS XR router?

• A. config-vrf
• B. config-vrf-af
• C. config-bgp
• D. config-bgp-af
• E. config-bgp-vrf

Answer: E

Explanation: http://www.cisco.com/en/US/docs/ios_xr_sw/iosxr_r3.6/routing/configuration/guide/rc36book.pdf

NEW QUESTION 18
Which Layer 2 protocol parameters can be carried inside the control word when implementing AToM service?

• A. PW ID
• B. Frame Relay FECN, BECN, and DE bits
• C. encapsulation type
• D. VC type

Answer: B

Explanation: http://www.cisco.com/en/US/products/ps6603/products_qanda_item09186a008009d4e3.shtml#wp39173
Q. How does Frame Relay over MPLS work?
A. Traffic is encapsulated in MPLS packets and forwarded across the MPLS network. When encapsulating Frame Relay over MPLS, the Frame Relay header and the frame check sequence {FCS} are stripped from the packet. The bits for Backward Explicit Congestion Notification {BECN}, Forward Explicit Congestion Notification {FECN}, Discard Eligibility {DE} and Command/Response {C/R} are carried across the MPLS network in the "Control Word" header.

NEW QUESTION 19
When implementing Layer 3 MPLS VPNs on Cisco IOS/IOS XE PE routers, which PE-to-CE routing protocol requires a separate routing process to be created for each VRF?

• A. EIGRP
• B. RIPv2
• C. OSPF
• D. BGP

Answer: C

NEW QUESTION 20
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