Update Cisco 642-885 examcollection

Q1. Which statement is correct regarding using the TTL threshold to define the delivery boundaries of multicast traffic? 

A. If a packet TTL is less than the specified TTL threshold, the packet is forwarded out of the interface 

B. If a packet TTL is greater or equal to the specified TTL threshold, the packet is forwarded out of the interface 

C. If a packet TTL is equal to the specified TTL threshold, the packet is dropped 

D. When a multicast packet arrives, the TTL threshold value is decremented by 1. If the resulting TTL threshold value is greater than or equal to 0, the packet is dropped 

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Q2. Refer to the Cisco IOS-XR configuration exhibit. 

The Cisco IOS-XR router is unable to establish any PIM neighbor relationships. What is wrong with the configuration? 

A. The configuration is missing: interface gi0/0/0/0 

ip pim sparse-mode interface gi0/0/0/1 ip pim sparse-mode interface loopback0 ip pim sparse-mode 

B. The configuration is missing: 

multicast-routing address-family ipv4 interface gi0/0/0/0 enable interface gi0/0/0/1 enable 

C. The auto-rp scoping configurations should be set to 1 not 16 

D. The RP address has not been configured using the rp-address router PIM configuration command 

E. PIM defaults to dense mode operations only, so PIM sparse mode must be enabled using the pim sparse-mode router PIM configuration command 

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Q3. What is one of the configuration errors within an AS that can stop a Cisco IOS-XR router from announcing certain prefixes to its EBGP peers? 

A. Some prefixes were mistagged with the no-export BGP community 

B. Some prefixes were set with an MED of 0 

C. The outbound BGP route policy only has set actions defined without any pass actions defined 

D. The inbound BGP route policy only has set actions defined without any pass actions defined 

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Q4. Which two statements regarding the BGP peerlngs are correct? (Choose two) 

A. On PE5,the incoming prefixes received from the 192.168.105.51 EBGP peer is limited to a maximum of 10 prefixes 

B. On PE5, the "rplin" inbound route policy is applied to the 192.168.105.51 EBGP peer 

C. On PE5, the "pass" outbound route policy is applied to the 192.168.105.51 EBGP peer 

D. PE5 has one EBGP peer (CE5) and two IBGP peers (P1 and PE6) 

E. PE5 has received a total of 60 prefixes from its neighbors 

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Q5. When configuring BFD, the multiplier configuration option is used to determine which value? 

A. The retry interval 

B. The number of BFD packets that can be lost before the BFD peer is declared "down" 

C. The minimum interval between packets accepted from the BFD peers 

D. The number of BFD echo packets that will be originated by the router 

E. The number of routing protocols that will use BFD for fast peer failure detection 

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Q6. Which two statements regarding Auto RP operations and implementations are correct? (Choose two.) 

A. Candidate RPs send RP announcements to the 224.0.1.39 multicast group, and the mapping agents send RP discovery messages to the 224.0.1.40 multicast group 

B. Every PIM-SM router must be configured with the RP mapping agent IP address 

C. Candidate RPs learn the IP address of the mapping agents via periodic RP discovery messages 

D. Administrative scoping can be configured to limit the scope of the RP announcements 

E. A Reverse Path Forwarding check is done on the RP discovery messages 

F. RP discovery messages are flooded hop by hop throughout the network as multicast to the all PIM routers multicast group with a TTL of 1 

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Q7. Which three statements regarding NAT64 operations are correct? (Choose three.) 

A. With stateful NAT64, many IPv6 address can be translated into one IPv4 address, thus IPv4 address conservation is achieved 

B. Stateful NAT64 requires the use of static translation slots so IPv6 hosts and initiate connections to IPv4 hosts. 

C. With stateless NAT64, the source and destination IPv4 addresses are embedded in the IPv6 addresses 

D. NAT64 works in conjunction with DNS64 

E. Both the stateful and stateless NAT64 methods will conserve IPv4 address usage 

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Q8. The IPv6 2002::/16 prefix is used in which kind of implementations? 

A. 6RD 

B. 6to4 

C. NAT64 

D. IPv6 Multicast 

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