Cisco 642-885 Online Practice Questions and Exam Preparation

Cisco 642-885 Online Questions & Answers

• Question 101:

  In Cisco IOS-XR, the maximum-prefix command, to control the number of prefixes that can be installed from a BGP neighbor, is configured under which configuration mode?

  A. RP/0/RSP0/CPU0:P2(config-bgp)#
  B. RP/0/RSP0/CPU0:P2(config-bgp-af)#
  C. RP/0/RSP0/CPU0:P2(config-bgp-nbr)#
  D. RP/0/RSP0/CPU0:P2(config-bgp-nbr-af)#
  D. RP/0/RSP0/CPU0:P2(config-bgp-nbr-af)#

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  http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a008010a28 a.shtml

• Question 102:

  When implementing high-availability stateful switchover BGP routing, in which situation would Cisco NSR be required?

  A. On the PE routers connecting to the CE routers which are not NSF aware or are not NSF capable
  B. On the PE routers connecting to the CE routers which support graceful restart
  C. On the PE routers connecting to the CE routers which are incapable of performing stateful switchover operations because the CE routers are only NSF aware but not NSF capable
  D. On the PE routers connecting to the CE routers which are incapable of performing stateful switchover operations because the CE routers are only NSF capable but not NSF aware
  E. On the service provider core P routers which are also NSF aware
  F. On the service provider core P routers which are also NSF capable
  A. On the PE routers connecting to the CE routers which are not NSF aware or are not NSF capable

• Question 103:

  

  

  On the PE, which two statements are correct regarding the(192.168.156.60,224.1.1.1) entry? (Choose two,)

  A. The RPF neighbor points towards the RP
  B. The RPF neighbor is reachable overthe Gi0/0/0/1 interface
  C. The OIL contains the GiO/0/0/0 interface
  D. The IIL is Null
  A. The RPF neighbor points towards the RP
  C. The OIL contains the GiO/0/0/0 interface

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  #show ip mroute

• Question 104:

  Which configuration would an engineer use to exchange IPv6 multicast routes via BGP with a neighbor that does not support the corresponding Multicast SAFI on Cisco IOS XE?

  A. router bgp 100 bgp router-id 209.165.201.10 no bgp default ipv4-unicast neighbor 2001:DB8::10 remote-as 201 neighbor 2001:DB8::10 update-source GigabitEthernet 0/10 address-family ipv6 multicast neighbor 2001:DB8::10 activate network 2001:DB8:CDCD:1::/64 exit-address-family
  B. router bgp 100 bgp router-id 209.165.201.10 no bgp default ipv4-unicast neighbor 2001:DB8::10 remote-as 201 neighbor 2001:DB8::10 update-source GigabitEthernet 0/10 address-family ipv6 neighbor 2001:DB8::10 translate-update ipv6 multicast unicast neighbor 2001:DB8::10 activate no synchronization exit address-family address-family ipv6 multicast neighbor 2001:DB8::10 activate network 2001:DB8:CDCD:1::/64 exit-address-family
  C. router bgp 100 bgp router-id 209.165.201.10 no bgp default ipv4-unicast neighbor 2001:DB8::10 remote-as 201 neighbor 2001:DB8::10 update-source GigabitEthernet 0/10 address-family ipv6 neighbor 2001:DB8::10 activate address-family ipv6 multicast neighbor 2001:DB8::10 activate network 2001:DB8:CDCD:1::/64 exit-address-family
  D. router bgp 100 bgp router-id 209.165.201.10 no bgp default ipv4-unicast neighbor 2001:DB8::10 remote-as 201 neighbor 2001:DB8::10 update-source GigabitEthernet 0/10 address-family ipv6 neighbor 2001:DB8::10 translate-update ipv6 multicast unicast no synchronization exit address-family address-family ipv6 multicast neighbor 2001:DB8::10 activate network 2001:DB8:CDCD:1::/64 exit-address-family
  E. router bgp 100 bgp router-id 209.165.201.10 no bgp default ipv4-unicast neighbor 2001:DB8::10 remote-as 201 neighbor 2001:DB8::10 update-source GigabitEthernet 0/10 address-family ipv6 neighbor 2001:DB8::10 send-label neighbor 2001:DB8::10 override-capability-neg neighbor 2001:DB8::10 activate no synchronization exit address-family address-family ipv6 multicast network 2001:DB8:CDCD:1::/64 exit-address-family
  B. router bgp 100 bgp router-id 209.165.201.10 no bgp default ipv4-unicast neighbor 2001:DB8::10 remote-as 201 neighbor 2001:DB8::10 update-source GigabitEthernet 0/10 address-family ipv6 neighbor 2001:DB8::10 translate-update ipv6 multicast unicast neighbor 2001:DB8::10 activate no synchronization exit address-family address-family ipv6 multicast neighbor 2001:DB8::10 activate network 2001:DB8:CDCD:1::/64 exit-address-family

• Question 105:

  When configuring PIM operations, what is the effect of setting the SPT threshold to infinity?

  A. The multicast source to the RP path will never switch over to the shortest path tree
  B. All the PIM routers will have more (S,G) states, thus consuming more router resources
  C. The receivers will be able to immediately switch over to the shortest path tree after receiving the first multicast packets on the shared tree via the RP
  D. The last-hop routers will never switch over to the shortest path tree and will always remain on the shared tree
  D. The last-hop routers will never switch over to the shortest path tree and will always remain on the shared tree

• Question 106:

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

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• Question 107:

  When a BGP route reflector receives an IBGP update from a non-client IBGP peer, the route reflector will then forward the IBGP updates to which other router(s)?

  A. To the other clients only
  B. To the EBGP peers only
  C. To the EBGP peers and other clients only
  D. To the EBGP peers and other clients and non-clients
  C. To the EBGP peers and other clients only

• Question 108:

  Refer to the exhibit.

  

  Which three statements are correct regarding the Cisco IOS-XR configuration? (Choose three.)

  A. This router, acting as the RP mapping agent, will send RP announcement messages to the 224.0.1.40 group
  B. This router, acting as the RP mapping agent, will send RP discovery messages to the 224.0.1.39 group
  C. This router is the RP mapping agent only for the 224.11.11.11 and 224.99.99.99 multicast groups
  D. This router is a candidate PIM-SM RP for the 224.99.99.99 multicast group
  E. This router is a candidate PIM-BIDIR RP for the 224.11.11.11 multicast group
  F. IGMPv3 is enabled on all interfaces
  G. Other routers will recognize this router as the RP for all multicast groups with this router loopback 0 IP address
  D. This router is a candidate PIM-SM RP for the 224.99.99.99 multicast group
  E. This router is a candidate PIM-BIDIR RP for the 224.11.11.11 multicast group
  F. IGMPv3 is enabled on all interfaces

• Question 109:

  Refer to the topology diagram shown in the exhibit and the partial configurations shown below.

  

  Once the attack from 209.165.201.144/28 to 209.165.202.128/28 has been detected, which additional configurations are required on the P1 IOS-XR router to implement source-based remote-triggered black hole filtering?

  ! router bgp 123 address-family ipv4 unicast redistribute static route-policy test !

  A. router static address-family ipv4 unicast 209.165.202.128/28 null0 tag 666 192.0.2.1/32 null0 tag 667 ! route-policy test if tag is 666 then set next-hop 192.0.2.1 endif if tag is 667 then set community (no-export) endif end-policy !
  B. router static address-family ipv4 unicast 209.165.201.144/28 null0 tag 666 192.0.2.1/32 null0 tag 667 ! route-policy test if tag is 666 then set next-hop 192.0.2.1 endif if tag is 667 then set community (no-export) endif end-policy !
  C. router static address-family ipv4 unicast 209.165.201.144/28 null0 tag 666 192.0.2.1/32 null0 ! route-policy test if tag is 666 then set next-hop 192.0.2.1 set community (no-export) endif end-policy
  D. router static address-family ipv4 unicast 209.165.202.128/28 null0 tag 666 192.0.2.1/32 null0 ! route-policy test if tag is 666 then set next-hop 192.0.2.1 set community (no-export) endif end-policy !
  C. router static address-family ipv4 unicast 209.165.201.144/28 null0 tag 666 192.0.2.1/32 null0 ! route-policy test if tag is 666 then set next-hop 192.0.2.1 set community (no-export) endif end-policy

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  : Source-Based RTBH Filtering With destination-based black holing, all traffic to a specific destination is dropped after the black hole has been activated, regardless of where it is coming from. Obviously, this could include legitimate traffic destined for the target. Source-based black holes provide the ability to drop traffic at the network edge based on a specific source address or range of source addresses. If the source address (or range of addresses) of the attack can be identified (spoofed or not), it would be better to drop all traffic at the edge based on the source address, regardless of the destination address. This would permit legitimate traffic from other sources to reach the target. Implementation of source-based black hole filtering depends on Unicast Reverse Path Forwarding (uRPF), most often loose mode uRPF. Loose mode uRPF checks the packet and forwards it if there is a route entry for the source IP of the incoming packet in the router forwarding information base (FIB). If the router does not have an FIB entry for the source IP address, or if the entry points to a null interface, the Reverse Path Forwarding (RPF) check fails and the packet is dropped, as shown in Figure 2. Because uRPF validates a source IP address against its FIB entry, dropping traffic from specific source addresses is accomplished by configuring loose mode uRPF on the external interface and ensuring the RPF check fails by inserting a route to the source with a next hop of Null0. This can be done by using a trigger device to send IBGP updates. These updates set the next hop for the source IP to an unused IP address that has a static entry at the edge, setting it to null as shown in Figure 2.

  

• Question 110:

  A network architect is responsible for the company's multicast network domain design. Which multicast component acts as a meeting place for sources and receivers?

  A. multicast shared tree
  B. multicast distribution point
  C. multicast rendezvous point
  D. multicast source tree
  C. multicast rendezvous point