Cisco 642-887 Free Practice Questions

NEW QUESTION 1
Only based on the Cisco IOS XR policy-map configuration exhibit,

which statement is correct?

• A. All DSCP AF41 marked packets will be dropped when the average queue length reaches 12,000 packets.
• B. DSCP AF11 marked packets will be randomly dropped when the average queue length reaches 10,000 packets.
• C. DSCP AF11 and AF41 marked packets are guaranteed a minimum bandwidth of 1 Mb/s.
• D. DSCP AF11 and AF41 marked packets are guaranteed a maximum bandwidth of 1 Mb/s.

Answer: B

NEW QUESTION 2
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 3
DRAG DROP

• A. Mastered
• B. Not Mastered

Answer: A

Explanation:
All network packets are treated exactly the same—Best Effort
It divides traffic classes and applies a different level of service for each class--Diffserv Traffic-handling characteristics are based on signaling events from network-based applications-- intServ
All network packets are treated exactly the same-- Best Effort
It divides traffic classes and applies a different level of service for each class-- Diffserv Traffic-handling characteristics are based on signaling events from network-based applications-- intServ

NEW QUESTION 4
Which are typical class-based marking policies that are implemented on service provider IP NGN PE routers?

• A. On the PE ingress, classify the customer traffic and then mark with qos-grou
• B. On the PE egress, classify based on the qos-group and then mark with mpls exp.
• C. On the PE ingress, classify the customer traffic and then mark with mpls ex
• D. On the PE egress, classify based on the mpls exp and then mark with qos-group.
• E. On the PE ingress, trust the customer QoS marking
• F. On the PE egress, classify based on the customer QoS markings and then mark with qos-group.
• G. On the PE ingress, trust the customer QoS marking
• H. On the PE egress, classify based on the customer QoS markings and then mark with mpls exp.

Answer: A

NEW QUESTION 5
When configuring LLQ (strict priority queue) on a traffic class using the Cisco IOS XR priority command on a Cisco ASR9K router, which additional QoS command is required for this traffic class?

• A. shape
• B. police
• C. random-detect
• D. bandwidth

Answer: B

Explanation:
The Low Latency Queueing feature brings strict priority queueing to Class-Based Weighted Fair Queueing (CBWFQ).

NEW QUESTION 6
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 7
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 8
Which two advantages are reasons that service providers might deploy MPLS? (Choose two.)

• A. to avoid using IGP in the core
• B. to facilitate smooth migrations between legacy WAN technologies
• C. to reduce the throughput overhead of full IPv4/IPv6 headers when traversing the core
• D. to reduce the computational requirements that are placed on router CPUs
• E. to reduce configuration and feature requirements in the core

Answer: CD

NEW QUESTION 9
DS-TE implementations on Cisco routers support which bandwidth pool(s) and class type(s)? (Choose two.)

• A. global pool only
• B. subpool only
• C. global pool and subpool
• D. class-type 0 only
• E. class-type 1 only
• F. class-type 0 and class-type 1

Answer: CF

Explanation:
Differential Service Tunnels
Differential Service Traffic Engineering (TE) is an extension of the regular MPLS Traffic Engineering (MPLSTE) feature. Regular TE does not provide bandwidth guarantees to different traffic classes. A single bandwidth pool (global pool) is used in regular TE that is shared by all traffic. In order to support various class of service (CoS), the ability to provide multiple bandwidth pools is required. These bandwidth pools then can be treated differently based on the requirement for the traffic class using that pool.
In RSVP global and subpools reservable bandwidths are configured on a per interface basis to accommodate TE tunnels on the node. Available bandwidth from all configured bandwidth pools is advertised using Interior Gateway Protocol (IGP). RSVP is used to signal the TE tunnel with appropriate bandwidth pool requirements.

NEW QUESTION 10
Referring to the show output exhibit, which statement is correct?

• A. The P1 router is receiving label information for the 10.0.2.1/32 prefix from two LDP peers.
• B. The P1 router is receiving label information for the 10.7.1.1/32 prefix from two LDP peers.
• C. The P1 router is using the IMP-NULL local label for the 10.7.1.1/32 prefix because 10.7.1.1/32 is the loopback interface IP address on the P1 router.
• D. The P1 router will perform PHP for the 10.7.1.1/32 and 10.7.10.1./32 prefixes.

Answer: B

NEW QUESTION 11
Which of the following three statements are correct regarding IPv6 QoS? (Choose three.)

• A. The traffic class field in the IPv6 header can be used to set specific precedence or DSCP values.
• B. A 20-bit flow label field enables per-flow processing.
• C. DS-TE is not supported by IPv6.
• D. Per-hop behavior in IPv6 networks is based on EXP bits.
• E. IPv6 QoS features are configured using the modular QoS CLI on Cisco routers.

Answer: ABE

Explanation:
http://www.cisco.com/en/US/technologies/tk648/tk872/technologies_white_paper0900aecd 8026004d.pdf

NEW QUESTION 12
Which two factors must you consider when configuring MPLS EXP? (Choose two.)

• A. MPLS EXP marking is supported in the egress direction
• B. A packet that IP ToS classifies at ingress can be reclassified by MPLS EXP at egress
• C. MPLS EXP marking is supported in the ingress direction
• D. MPLS EXP classification for bridged MPLS packets on EVCs is supported
• E. A packet that MPLS classifies at ingress can be reclassified by IP ToS at egress

Answer: CE

NEW QUESTION 13
Refer to the exhibit. From which table was the information obtained?

• A. FIB
• B. CEF
• C. LIB
• D. LFIB

Answer: D

NEW QUESTION 14
On Cisco routers, how is hierarchical QoS implemented?

• A. Within the parent policy, reference another child policy using the policy-map command.
• B. Within the child policy, reference another parent policy using the policy-map command.
• C. Use the policy-map command within a service-policy to implement nested policy-maps.
• D. Within the parent policy-map, reference another child policy-map using the service- policy command.

Answer: D

NEW QUESTION 15
Which option is the correct definition of the LB on a Cisco router?

• A. a table used by switching functions to forward labeled packets
• B. a table that holds the next hop for destination prefixes
• C. a label-based adjacency table
• D. a table that stores remote and local label bindings

Answer: A

NEW QUESTION 16
Which QoS mechanism is used for congestion avoidance?

• A. LLQ
• B. CBWFQ
• C. WRED
• D. LFI
• E. traffic policing

Answer: C

NEW QUESTION 17
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 18
LDP session protection uses which one to maintain the LDP session between LDP neighbors?

• A. LDP NSF
• B. LDP NSR
• C. backup-targeted LDP hellos
• D. BFD
• E. LDP-IGP synchronization

Answer: C

NEW QUESTION 19
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: AC

NEW QUESTION 20
Which two options are true regarding the Pipe and Short Pipe MPLS tunneling models? (Choose two.)

• A. In Short Pipe mode QoS is done on the PE-to-CE link based on the customer’s PHB markings
• B. In Pipe mode QoS is done on the PE-to-CE link based on the service provider’s PHB markings
• C. In Pipe mode QoS is done on the PE-to-CE link based on the customer’s PHB markings
• D. In Short Pipe mode QoS is done on the PE-to-CE link based on the service provider’s PHB markings
• E. Short Pipe mode does not need MPLS usage, but Pipe mode does

Answer: AB

NEW QUESTION 21
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