Cisco 642-887 Guidance 2021

NEW QUESTION 1
An engineer wants to extend the trust boundary to a Cisco IP Phone. Which protocol should be used?

• A. CDP
• B. CoS
• C. ToS
• D. 802.1Q

Answer: A

NEW QUESTION 2
On the Cisco IOS XR, which MQC configuration is different than on the Cisco IOS and IOS XE?

• A. On the Cisco IOS XR, WRED can only be applied in the output direction.
• B. On the Cisco IOS XR, marking can only be applied in the input direction.
• C. On the Cisco IOS XR, LLQ can be applied in the input or output direction.
• D. On the Cisco IOS XR, LLQ can use up to four priority queues: level 1, level 2, level 3, and level 4.

Answer: C

NEW QUESTION 3
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: ACEF

NEW QUESTION 4
A network engineer must make a reservable maximum bandwidth of 75 Mbps on a Cisco ASR 9000 series router. Which configuration satisfies this requirement in Cisco IOS XR?

• A. 2802_FY14Q4_CORE_Q33_o1
• B. 2813_FY14Q4_CORE_Q33_o2
• C. 2824_FY14Q4_CORE_Q33_o3
• D. 2835_FY14Q4_CORE_Q33_o4

Answer: C

NEW QUESTION 5
Which two fields are in the traffic engineering topology database? (Choose two.)

• A. TE-metric
• B. IGP metric
• C. link delay
• D. LSP setup priority
• E. LDP authentication

Answer: AD

NEW QUESTION 6
An engineer deployed a Cisco MPLS TE next-hop protection over a switched environment. While testing the link protection, an excessive IGP delay in the reconvergence time is seen. Which action fixes this issue?

• A. Replace the existing link with a routed back-to back link
• B. Configure object tracking
• C. Set up more aggressive IGP timers
• D. Implements BFD on the link

Answer: B

NEW QUESTION 7
Which protocol is used to send MPLS OAM traffic over an MPLS network?

• A. ICMP
• B. IP protocol number 137
• C. TCP
• D. UDP

Answer: D

NEW QUESTION 8
When implementing MPLS TE tunnels on Cisco IOS XR routers, what is the tunnel setup and hold priority value range, and which value has the highest priority?

• A. 0-63, where 0 is the highest priority
• B. 0-63, where 63 is the highest priority
• C. 0-7, where 0 is the highest priority
• D. 0-7, where 7 is the highest priority

Answer: C

NEW QUESTION 9
A company asks an engineer to provide an explanation for implementing MPLS DiffServ- TE services. Which option is a DiffServ-TE fundamental concept that should be highlighted?

• A. expedited forwarding
• B. assured forwarding
• C. class of service
• D. class types
• E. fast reroute

Answer: D

NEW QUESTION 10
An LDP session is established between two neighbors. Over which protocol and port number do they maintain their adjacency?

• A. TCP 711
• B. UDP 646
• C. UDP 711
• D. TCP 646

Answer: D

NEW QUESTION 11
Scenario:




From PE8 router, what is the label action used to reach the P2 loopback 0 interface 10.0.2.1/32?

• A. Swap label 35 with label 16004
• B. Push label 16004
• C. Pop label 35
• D. Pop label 16009
• E. Push Label 16009
• F. Swap label 35 with label 16009

Answer: C

Explanation:
show mpls forwarding-table , find prefix 10.0.2.1 and you will see there under outgoing Label "Pop Label" (This is actually logic because the prefix is directly connected and therefore the packet will forward without label). If the router should forward any packet to that prefix, the packet should be received with Local label on PE8 (Local Label = 35), the router will remove it and forward it without Label.

NEW QUESTION 12
Which feature should you configure to enable routers to maintain MPLS label information despite link flaps on an interface?

• A. Targeted Adjacency
• B. IGP Synchronization
• C. MPLS LDP Session Protection
• D. NSR

Answer: C

NEW QUESTION 13
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

NEW QUESTION 14
Which option describes the IPv6 flow label field?

• A. a 3-bit field used for marking a traffic flow
• B. an 8-bit field used for labeling a traffic flow
• C. a 20-bit field used to tag a traffic flow throughout the network
• D. an 8-bit field out of which the first 6 are used to classify packets

Answer: C

NEW QUESTION 15
Referring to the Cisco IOS XR show command output exhibit, what are three possible reasons that the GigabitEthernet0/1/0/10 LDP IGP sync status is not ready? (Choose three.)

• A. GigabitEthernet0/1/0/10 is not configured to run LDP.
• B. Graceful restart is not configured on the peer.
• C. The LDP neighbor on GigabitEthernet0/1/0/10 is not up.
• D. The OSPF neighbor on GigabitEthernet0/1/0/10 is not up.
• E. LDP is up on GigabitEthernet0/1/0/10, but no label bindings have been received from the peer.
• F. GigabitEthernet0/1/0/10 is a member link of Bundle-Ether9000.

Answer: CDE

NEW QUESTION 16
DRAG DROP

• A. Mastered
• B. Not Mastered

Answer: A

Explanation:
Place the options in the following order: Traffic Policing
WRED LLQ
Traffic Shaping

NEW QUESTION 17
On Cisco routers, which QoS marker is only locally significant?

• A. DSCP
• B. MPLS EXP
• C. IP precedence
• D. QoS group
• E. discard eligible (DE)

Answer: D

NEW QUESTION 18
Referring to the traceroute output exhibit that is shown,

which statement is correct?

• A. There is no problem with the end-to-end LSP as indicated by the successful trace.
• B. Normal PHP operation is performed by the hop 4 router.
• C. The end-to-end LSP is broken at hop 4.
• D. At each hop, each LSR is able to perform label swapping.

Answer: C

NEW QUESTION 19
Refer to the exhibit.

A network engineer who is working for an ISP wants to override the QoS that comes from the customer. The engineer wants to set a QoS value of 5 for all traffic. What are two reasons why the configuration is not working? (Choose two.)

• A. The service-policy command should point to the service policy, not to the class map
• B. The set command should reference CoS instead of MPLS EXP bits
• C. The service-policy configuration should be set as output
• D. The policy-map configuration needs to reference class-map Custom1
• E. The number 350 in the xconnect command should appear after the encapsulation type

Answer: AD

NEW QUESTION 20
With unmanaged CE routers, at which point in the service provider network is the QoS trust boundary, and what is required at the trust boundary?

• A. between the CE and PE router and mapping of the customer traffic classes into the service provider traffic classes at the PE router ingress
• B. between the CE and PE router and trusting the QoS markings from the CE router and applying the required QoS mechanisms based on the customer QoS markings
• C. between the PE and the P router and mapping of the customer traffic classes into the service provider traffic classes at the P router ingress
• D. between the PE and P router and trusting the QoS markings from the CE router and applying the required QoS mechanisms based on the customer QoS markings
• E. between the customer network and the CE router ingress and applying the required egress QoS policy on the CE router

Answer: A

NEW QUESTION 21
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

NEW QUESTION 22
An engineer has been tasked to configure a guaranteed 2 Mbps of bandwidth for outgoing FTP traffic on interface FastEthernet 1/1/1 on Cisco IOS XR. Which method accomplishes this configuration?

• A. configure terminal class-map FTP_CLASS match protocol ftpexitpolicy-map POLICY_1 class FTP_CLASS bandwidth 2000exit exitinterface FastEthernet 1/1/1 service-policy output POLICY_1 endcommit
• B. configure terminal class-map FTP_CLASS match protocol ftpexitpolicy-map POLICY_1 class FTP_CLASS bandwidth 2000000 exitexitinterface FastEthernet 1/1/1 service-policy input POLICY_1 endcommit
• C. configure terminalaccess-list 100 permit ip any any eq 21 policy-map POLICY_1match ip access-list 100 bandwidth 2000exit exitinterface FastEthernet 1/1/1 service-policy output POLICY_1 endcommit
• D. configure terminal policy-map POLICY_1 class FTP_CLASS match protocol ftp bandwidth 2000000 exitexitinterface FastEthernet 1/1/1 service-policy input POLICY_1 endcommit

Answer: A

NEW QUESTION 23
An engineer is deploying CB-WRED across the entire core network to enforce the previously deployed CBWFQ and decides to change the WRED default to make it work with DSCP. Which policy-map command enables this new profile on regular Cisco IOS routers?

• A. random-detect
• B. random-detect dscp value
• C. random-detect dscp based
• D. random-detect precedence value

Answer: C

NEW QUESTION 24
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