642-889 Implementing Cisco Service Provider Next-Generation Egde Network Services

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Question 1

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

Question 2

Which Layer 2 VPN technology is implemented over an IP core network without the need
for MPLS?

  • A. VPLS
  • B. VPWS
  • C. AToM
  • D. L2TPv3


Answer : D

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

Question 3

An engineer is configuring an EoMPLS circuit on a Cisco IOS XR router interface that
removes a VLAN from the distribution layer. Which configuration accomplishes this
configuration?

  • A. interface GigabitEthernet 0/10.10 l2transport encapsulation dot1q 10 l2vpn xconnect group 103588 p2p 103588 interface GigabitEthernet 2/10.10 neighbor ipv4 10.10.10.2 pw-id 103588
  • B. interface GigabitEthernet 0/10.10 encapsulation dot1q 10 rewrite ingress tag pop 1 symmetric l2vpn xconnect group 103588 p2p 103588 interface GigabitEthernet 0/10.10 neighbor ipv4 10.10.10.2 pw-id 103588
  • C. interface GigabitEthernet 0/10.10 l2transport encapsulation dot1q 10 rewrite ingress tag pop 1 symmetric l2vpn xconnect group 103588 p2p 103588 interface GigabitEthernet 0/10.10 neighbor ipv4 10.10.10.2 pw-id 103588
  • D. interface GigabitEthernet 0/10.10 l2transport encapsulation dot1q 10 rewrite ingress tag translate 1-to-1 dot1ad 10 symmetric l2vpn xconnect group 103588 p2p 103588 interface GigabitEthernet 0/10.10 neighbor ipv4 10.10.10.2 pw-id 103588


Answer : C

Question 4

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 subnetbecause 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 subnetbecause 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

Question 5

A routing entry on a PE router has an ext-hop address of ::ffff:[IP ADDRESS]. Which
service provider technology is being deployed?

  • A. 6VPE
  • B. 6PE
  • C. 4to6 tunnel
  • D. 6to4 tunnel


Answer : B

Question 6

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

Question 7





On PE7, which interface connects to the CE7 and what is the name of the VRF that
interface is associated to? (Choose two.)

  • A. Gi0/0/0/0
  • B. Gi0/0/0/1
  • C. Gi0/0/0/2
  • D. Customer_1
  • E. Customer_A
  • F. Customer_CE7


Answer : B,C

Explanation: #show ip vrf interfaces

Question 8

When implementing VPLS on Cisco IOS XR routers, the VPLS PW neighbors can be
statically defined under which configuration mode?

  • A. bridge group
  • B. bridge-domain
  • C. vfi
  • D. mpls ldp
  • E. l2transport


Answer : C

Question 9

When implementing MPLS Layer 3 VPN services, which CE-PE routing method does not
require the use of the redistribute command to enable the customer routes to be advertised
through the MPLS cloud between the customer sites?

  • A. EIGRP
  • B. OSPF
  • C. IS-IS
  • D. BGP
  • E. static routing
  • F. OSPF or IS-IS


Answer : D

Question 10

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

Question 11

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

Question 12




On PE7, what is the pseudowire ID that connects to the 10.8.1.1 neighbor?

  • A. 70
  • B. 80
  • C. 123
  • D. 0x840001
  • E. 0x4000080


Answer : C

Question 13

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 VPNCarrier Supporting CarrierIPv4 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 14

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

Question 15

Which organization provides and promotes a standards-based description of service
provider services offering?

  • A. MEF
  • B. IETF
  • C. IEEE
  • D. ITU


Answer : A

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