Implementing Cisco Service Provider Next-Generation Core Network Services v7.0 (642-887)

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Total 133 questions

Which configuration fulfills the requirement of configuring LDP with Cisco Nonstop
Forwarding on a router with 5 minutes time to hold the forwarding table information and 1 minute retry timer value for an LDP connection?

  • A. mpls ldp graceful-restart graceful-restart forwarding state-holdtime 5 graceful-restart reconnect-timeout 1 interface GigabitEthernet0/0/0/0 !
  • B. mpls ldp graceful-restart graceful-restart forwarding state-holdtime 300 graceful-restart reconnect-timeout 60 interface GigabitEthernet0/0/0/0 !
  • C. mpls ldp nsr graceful-restart graceful-restart forwarding state-holdtime 300 graceful-restart reconnect-timeout 60 interface GigabitEthernet0/0/0/0 !
  • D. mpls ldp nsr graceful-restart graceful-restart forwarding state-holdtime 5 graceful-restart reconnect-timeout 1 interface GigabitEthernet0/0/0/0 !


Answer : B

Which Cisco IOS XR command should be used in order to enable LDP on all interfaces for which the IGP protocol is enabled?

  • A. RP/0/0/CPU0:R1(config-ospf)#mpls ldp auto-config
  • B. RP/0/0/CPU0:R1(config-ospf)#mpls ldp interface all enable
  • C. RP/0/0/CPU0:R1(config-ospf)#enable all
  • D. RP/0/0/CPU0:R1(config-ldp)#enable all


Answer : A

A service provider recently defined new SLA services that provide QoS transparency over
MPLS DiffServ-TE services. Which two tunneling modes provide QoS transparency?
(Choose two.)

  • A. short pipe mode
  • B. uniform mode
  • C. pipe mode with an explicit NULL LSP
  • D. pipe mode without a explicit NULL LSP
  • E. best effort mode


Answer : A,C

When using the tunnel mpls traffic-eng path-option 1 explicit name test command in Cisco
MPLS TE tunnel configurations, the test explicit-path configuration will consist of a list of which values?

  • A. tunnel endpoint
  • B. resource class affinity
  • C. MPLS label
  • D. IP address


Answer : D

Explanation:
tunnel mpls traffic-eng path-option
To configure a path option for a Multiprotocol Label Switching (MPLS) traffic engineering tunnel, use the tunnel mpls traffic-eng path-option command in interface configuration mode. To disable the specified path option, use the no form of this command. tunnel mpls traffic-eng path-option number {dynamic | explicit {name path-name | path-number}} [lockdown] no tunnel mpls traffic-eng path-option number {dynamic | explicit {name path-name
| path-number}} [lockdown]

Syntax Description -
number = When multiple path options are configured, lower numbered options are preferred. dynamic = Path of the LSP is dynamically calculated. explicit = Path of the LSP is an IP explicit path. name path-name = Path name of the IP explicit path that the tunnel uses with this option. path-number = Path number of the IP explicit path that the tunnel uses with this option. lockdown = (Optional) The LSP cannot be reoptimized.

Usage Guidelines -
You can configure multiple path options for a single tunnel. For example, there can be several explicit path options and a dynamic option for one tunnel. Path setup preference is for lower (not higher) numbers, so option 1 is preferred.

Examples -
The following example shows how to configure the tunnel to use a named IP explicit path:
Router(config-if)# tunnel mpls traffic-eng path-option 1 explicit name test

Which method maps MPLS EXP bit 5 to COS 5 on Cisco IOS XE?

  • A. configure terminal class-map match exp match mpls experimental topmost 5 exit policy-map EXP2Cos class exp set cos 5 exit class class-default random-detec interface fastethernet 0/0 service-policy output EXP2Cos
  • B. configure terminal class-map match exp match mpls experimental topmost 5 exit policy-map EXP2Cos class exp set cos 5 exit class class-default random-detec interface fastethernet 0/0 service-policy input EXP2Cos
  • C. configure terminal class-map match exp match mpls cos 5 exit policy-map EXP2Cos class exp set mpls experimental topmost 5 exit class class-default random-detec interface fastethernet 0/0 service-policy output EXP2Cos
  • D. configure terminal class-map match exp match mpls cos 5 exit policy-map EXP2Cos class exp set mpls experimental topmost 5 exit class class-default random-detec interface fastethernet 0/0 service-policy output EXP2Cos exit commit
  • E. configure terminal ip access-list 101 permit ip any any mpls experimental 5 class-map match exp match access-group 101 exit policy-map EXP2Cos class exp set cos 5 exit class class-default random-detec interface fastethernet 0/0 service-policy output EXP2Cos exit


Answer : A

Refer to the exhibit. From which table was the information obtained?


  • A. FIB
  • B. CEF
  • C. LIB
  • D. LFIB


Answer : D

An engineer is working in a service provider environment to troubleshoot a MPLS VPN.
The engineer determines that LDP neighborship is flapping between two routers and causing disruption to the traffic. Which LDP feature can help to solve the issue?

  • A. LDP Discovery
  • B. LDP auto-configuration
  • C. LDP graceful-restart
  • D. LDP NSF


Answer : C

A network operations center requests support to configure a Cisco MPLS TE tunnel on a
Cisco IOS XR router. Which command sets a specific bandwidth required to the corresponding Cisco MPLS TE tunnel?

  • A. rsvp interface interface-path-id bandwidth bandwidth
  • B. interface tunnel-te tunnel_id ! bandwidth bandwidth
  • C. interface tunnel-te tunnel_id ! signaled-bandwidth bandwidth
  • D. mpls traffic-eng auto-bw collect frequency value !


Answer : C

On a Cisco router, when will the router actually reserve the bandwidth for the MPLS traffic engineering tunnel?

  • A. during the autoroute process
  • B. during constraint-based routing calculations
  • C. on the receipt of the RSVP Path message
  • D. on the receipt of the RSVP Resv message


Answer : D

The Cisco IOS and IOS XE qos pre-classify command allows which kind of packet classification on IP packets that are encapsulated with GRE and IPsec?

  • A. allows for packets to be classified based on the ToS byte values before packet encryption
  • B. allows for packets to be classified based on the ToS byte values after packet encryption
  • C. allows for packets to be classified based on the packet payload before packet encryption
  • D. allows for packets to be classified based on the packet payload after packet encryption
  • E. allows for packets to be classified based on the packet header parameters other than the ToS byte values after packet encryption


Answer : E

Which four options describe the functions of the control world in an AToM environment?
(Choose four.)

  • A. It carries generic and Layer 2 payload-specific information.
  • B. It prevents fragmentation and reassembly.
  • C. It preserves the sequence of the transported frames.
  • D. It is responsible for padding all packets.
  • E. It is responsible for padding the small packets.
  • F. It enables proper load balancing without packet desequencing independent of L2VPN packet content.
  • G. It enables an optimal path for the L2VPN packet content to follow through the MPLS backbone.
  • H. It carries Layer 2 payload-specific information.


Answer : A,C,E,F

When configuring class-based WRED on Cisco routers, which WRED parameter is not user configurable on a Cisco IOS XR but is user configurable on a Cisco IOS and IOS XE?

  • A. the ingress or egress direction where the class-based WRED policy will be applied
  • B. the maximum threshold
  • C. the minimum threshold
  • D. the mark probability denominator


Answer : D

Explanation:
Comparison of Cisco IOS QoS and Cisco IOS-XR QoS
The Cisco IOS-XR software implementation of QoS is basically the same as the QoS implementation on Cisco
IOS software, with the following exceptions:
On Cisco IOS-XR software, the bandwidth command can be configured only in egress policies.
The following changes have been made to the class-map command on Cisco IOS-XR software:
Supports 4K per logical router.
Maximum number of match criteria configurable in one class map is eight.
When a class is marked as high priority using the priority command on Cisco IOS-XR software, we recommend that you configure a policer to limit the priority traffic. Limiting the priority traffic will ensure that the priority traffic does not starve all of the other traffic on the line card. Use the police command to explicitly configure the policer.
On Cisco IO-XR software, only one conform-action, exceed-action, or violate-action command can be configured at a time. To configure traffic policing, use the police command.
On Cisco IOS-XR software, policy modifications cannot be made on existing policies. Use the policy-map command to remove the policy from all attached interfaces, delete the policy map, and redefine a new policy.
When configuring a policy map on Cisco IOS-XR software, the maximum number of classes configurable in one policy map is 16, which includes both Level 1 and Level 2 classes. To configure a policy map, use the policy-map command.
When WRED is configured on Cisco IOS-XR software, the mark probability in the random- detect command is not configurableit is always set to 1.
When the random-detect exp command is used on Cisco IOS-XR software, the exponential weighting constant is not configurable and will be programmed automatically by Cisco IOS-XR software.
When access control lists (ACLs) are used in QoS class maps, the underlying deny or permit actions associated with access control entries (ACEs) are ignored. ACEs are used as a classification mechanism in order to provide appropriate QoS behavior as specified in class maps. Use ACLs that include ACEs with permit actions only.

Which two statements are correct in describing ISP environments that are running IP/MPLS in the core network? (Choose two.)

  • A. On the PE routers, each BGP route must use a unique label to reach the BGP next hop.
  • B. The BGP next hops point to the PE routers, and only the PE routers are required to run BGP.
  • C. A full mesh of IBGP sessions are required between all of the PE and P routers to ensure proper packets forwarding.
  • D. The PE and P routers run LDP to learn the labels for reaching the BGP next-hop addresses.


Answer : B,D

Which three steps are required to configure QPPB on Cisco IOS XR routers? (Choose three.)

  • A. Apply a QPPB route policy to the BGP process using the table-policy command
  • B. Apply a QPPB route policy to the BGP neighbor using the route-policy command
  • C. Define a QPPB route policy to match the customer routes, then set the IP precedence or qos-group
  • D. Define a QPPB route policy to match the customer IP precedence or qos-group markings, then set the BGP community
  • E. Enable QPPB on an interface using the ipv4 bgp policy propagation input ip- precedence|qos-group destination|source command
  • F. Enable QPPB on an interface using the ipv4 bgp policy propagation output ip- precedence|qos-group destination|source command


Answer : A,C,E

Explanation:
QoS Policy Propagation via BGP (QPPB), is a mechanism that allows propagation of quality of service (QoS) policy and classification by the sending party based on access lists, community lists and autonomous system paths in the Border Gateway Protocol
(BGP), thus helping to classify based on destination instead of source address.

On Cisco routers, which three methods can be used to map traffic into the MPLS traffic engineering tunnel? (Choose three.)

  • A. on-demand routing
  • B. static routing
  • C. optimized edge routing
  • D. policy-based routing
  • E. autoroute


Answer : B,D,E

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Total 133 questions