642-887 | Downloadable 642-887 Testing Engine 2021

NEW QUESTION 1
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

NEW QUESTION 2
Which Cisco IOS XR high-availability feature is used to prevent routes from being used before LDP converges?

• A. LDP session protection
• B. LDP-IGP synchronization
• C. BFD
• D. IGP session protection

Answer: B

NEW QUESTION 3
Which two features are used to provide Cisco MPLS TE node and link protection? (Choose two.)

• A. autoroute
• B. fast reroute
• C. backup tunnels
• D. BFD

Answer: BC

NEW QUESTION 4
Which affinity and mask value will match the link affinity that has 0x0F in the first 8 bits and
0x01 in the last 8 bits, and the middle 16 bits can be any value?

• A. affinity 0x0F000001 mask 0x0F000001
• B. affinity 0x0F000001 mask 0x00000000
• C. affinity 0x0F000001 mask 0x11111111
• D. affinity 0x0F000001 mask 0x11000011
• E. affinity 0x0F000001 mask 0xFF0000FF
• F. affinity 0x0F000001 mask 0x00FFFF00

Answer: E

NEW QUESTION 5
An engineer must configure a policy on a Cisco IOS XE router that achieves the following: Traffic 2 Mbps or less is transmitted
Traffic between 2 Mbps and 3 Mbps is marked with IP Precedence 4 Traffic that exceeds 3 Mbps is dropped
Which configuration achieves this policy?

• A. Option A
• B. Option B
• C. Option C
• D. Option D

Answer: C

NEW QUESTION 6
An engineer is tasked to deploy Fast Reroute for Cisco MPLS TE. Which LSR is in charge to request the Fast Reroute capability along the LSP?

• A. point of local repair
• B. tail end router
• C. ingress and egress PE routers
• D. head-end router
• E. BGP routers acting as route reflectors

Answer: D

NEW QUESTION 7
Refer to the exhibit. Which configuration error prevents this traffic-shaping policy from working?

• A. The WAN interface is starting to drop packets because no queuing mechanism is implemented.
• B. Traffic-shaping policies are applied only in the outbound direction.
• C. The class_A configuration shape peak is used to maximize the serial interface performances.
• D. The service-policy command is applied only on logical or channeled interfaces.

Answer: B

NEW QUESTION 8
An engineer wants to implement constraint-based routing. Which MPLS application should the engineer use?

• A. unicast IP routing
• B. MPLS VPN
• C. MPLS TE
• D. RSVP

Answer: C

NEW QUESTION 9
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 10
At which layer does Cisco recommend the QoS trust boundary be set for an enterprise network environment?

• A. core layer, facing the distribution layer
• B. distribution layer, facing the access layer
• C. access layer, facing the end hosts
• D. distribution layer, facing the core layer

Answer: C

NEW QUESTION 11
On the Cisco IOS XR, when using the match protocol command within a class-map to classify traffic, you noticed that the match protocol option on the Cisco IOS XR shows much fewer protocol options than on the Cisco IOS or IOS XE, like there is no option such as the match protocol yahoo-messenger command on the Cisco IOS XR. Why is this?

• A. because the Cisco IOS XR router does not have the correct software packages installed
• B. because when defining the class-map, the class-map type should be set to type inspect: class-map type inspect class-map-name command
• C. because NBAR is not supported on the Cisco IOS XR
• D. because flexible packet matching has not been enabled on the Cisco IOS XR router

Answer: C

NEW QUESTION 12
Which four options are methods by which labels can be assigned in the label stack to an IP prefix? (Choose four.)

• A. LDP
• B. CEF
• C. BGP
• D. RSVP
• E. static
• F. IGP
• G. route recursion
• H. manual tagging

Answer: ACDG

NEW QUESTION 13
Which three commands are used to troubleshoot why IP packets are not forwarded on the LSP? (Choose three.)

• A. show cef prefix/length to check the prefix information
• B. debug mpls ldp transport events to display events related to the LDP peer discovery mechanism
• C. show mpls forwarding labels <label-id> hardware egress location <node-id> to check the hardware label FIB
• D. show arp <prefix> location <node-id> for the next hop prefix
• E. show mpls ldp discovery for the corresponding label information
• F. debug mpls ea platform all to display MPLS setup events and errors

Answer: ACD

NEW QUESTION 14
Which statement describes the QoS behavior between P and PE routers of an MPLS provider network for an L3VPN service?

• A. The PE function honors DSCP markings set by the CE.
• B. The customer and provider must agree on DSCP classification and traffic priorities.
• C. Classification of customer traffic is handled by the P router.
• D. The PE function cannot map DSCP markings to MPLS EXP bits.

Answer: B

NEW QUESTION 15
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 16
A company is experiencing congestion on Internet T1 links that transport site-to-site IPsec tunnels between head offices. QoS configuration is being modified on these T1 links. Which option describes the result from this QoS configuration?

• A. VPN traffic is unaffected because the inner ToS field is encrypted and hidden from the policy
• B. The physical interface is affected by the new QoS configuration
• C. The internal VPN logical interface reflects the new QoS service policy
• D. IPsec protocol applications work independently of the QoS configuration

Answer: A

NEW QUESTION 17
In Cisco MPLS TE implementations, what can cause the tunnel bandwidth to adjust automatically based on the traffic load in the tunnel?

• A. fast reroute
• B. admin weight
• C. autobandwidth
• D. bandwidth subpool

Answer: C

NEW QUESTION 18
The regional operation center deploys a Cisco MPLS TE tunnel over the company's core network. The Cisco MPLS TE tunnel is up and no error is detected, but no traffic is traversing the tunnel. Which two issues are possible causes? (Choose two.)

• A. The provider edge router is not performing the correct redistribution.
• B. The interior gateway protocol has no knowledge of the Cisco MPLS TE tunnel.
• C. No static route has been defined to route data traffic over the Cisco MPLS TE tunnel.
• D. The customer edge router is injecting rogue IPv4 prefixes in the provider edge routing table.
• E. The end-to-end label switched path has not been established.

Answer: BC

NEW QUESTION 19
When implementing CBWFQ, where should Weighted Random Early Detection configuration be applied?

• A. route-map
• B. policy-map
• C. class-map
• D. service-policy

Answer: B

NEW QUESTION 20
A network architect recently deployed AToM solutions for large enterprises over a service provider core
network. The architect now asks to deploy QoS over the same VPN to reinforce the SLA for these customers.
Which MPLS label field can be used for this purpose?

• A. discard/eligibility field
• B. type of service
• C. last 8 bits
• D. experimental bits

Answer: D

NEW QUESTION 21
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 22
A network engineer must analyze RSVP-TE signaling on a syslog server. Which three RSVP messages are valid? (Choose three.)

• A. RSVP PATH
• B. RSVP RESERVATION
• C. RSVP ESTABLISHED
• D. RSVP PATH TEAR
• E. RSVP KILL
• F. RSVP INIT

Answer: ABD

NEW QUESTION 23
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: A

Explanation:
http://www.cisco.com/en/US/tech/tk543/tk545/technologies_tech_note09186a008017405e. shtml
The qos pre-classify command
When packets are encapsulated by tunnel or encryption headers, QoS features are unable to examine the original packet headers and correctly classify the packets. Packets traveling across the same tunnel have the same tunnel headers, so the packets are treated identically if the physical interface is congested. With the introduction of the Quality of Service for Virtual Private Networks (VPNs) feature, packets can now be classified before tunneling and encryption occur.
In this example, tunnel0 is the tunnel name. The qos pre-classify command enables the QoS for VPNs feature on tunnel0:
Router(config)# interface tunnel0
Router(config-if)# qos pre-classify

NEW QUESTION 24
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