Precise 642-885 Software 2021

NEW QUESTION 1
Refer to the exhibit.

XR4 must protect itself from a DOS attack against its BGP process from R1 by using the TTL security feature. Which configuration achieves this goal?

• A. router bgp 100neighbor 10.10.14.1 ttl-security
• B. router bgp 100neighbor 10.10.14.1 ttl-security hops 1
• C. router bgp 100neighbor 10.10.14.1 ttl-security hops 254
• D. router bgp 100neighbor 10.10.14.1 ttl-security hops 255

Answer: A

NEW QUESTION 2
In Cisco IOS-XR, the ttl-security command is configured under which configuration mode?

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

Answer: C

Explanation:
http://packetlife.net/blog/2009/nov/23/understanding-bgp-ttl-security/

NEW QUESTION 3
Refer to the exhibit.

Given the partial BGP configuration, which configuration correctly completes the Cisco IOS-XR route reflector configuration where both the 1.1.1.1 and 2.2.2.2 routers are the clients and the 3.3.3.3 router is a non-client IBGP peer?

• A. neighbor 1.1.1.1remote-as 65123 route-reflector-client neighbor 2.2.2.2remote-as 65123 route-reflector-client neighbor 3.3.3.3remote-as 65123
• B. neighbor 1.1.1.1 address-family ipv4 unicast remote-as 65123route-reflector-client neighbor 2.2.2.2address-family ipv4 unicast remote-as 65123route-reflector-client neighbor 3.3.3.3address-family ipv4 unicast remote-as 65123
• C. neighbor 1.1.1.1remote-as 65123address-family ipv4 unicast route-reflector-client neighbor 2.2.2.2remote-as 65123address-family ipv4 unicast route-reflector-client neighbor 3.3.3.3remote-as 65123
• D. neighbor 1.1.1.1 remote-as 65123neighbor 1.1.1.1 route-reflector-clientneighbor 2.2.2.2 remote-as 65123neighbor 2.2.2.2 route-reflector-clientneighbor 3.3.3.3 remote-as 65123

Answer: C

NEW QUESTION 4
Which multicast group range is reserved for SSM?

• A. 224.0.0.0/8
• B. 225.0.0.0/8
• C. 232.0.0.0/8
• D. 239.0.0.0/8

Answer: C

Explanation:
PIM-SSM Operations
PIM in Source Specific Multicast operation uses information found on source addresses for a multicast group provided by receivers and performs source filtering on traffic.
•By default, PIM-SSM operates in the 232.0.0.0/8 multicast group range for IPv4 and ff3x::/32 (where x is any valid scope) in IPv6. To configure these values, use the ssm range command.
•If SSM is deployed in a network already configured for PIM-SM, only the last-hop routers must be upgraded with Cisco IOS XR software that supports the SSM feature.
•No MSDP SA messages within the SSM range are accepted, generated, or forwarded

NEW QUESTION 5
With IPv6 multicast, which feature can be used as a replacement method for static RP configuration?

• A. PIM Snooping
• B. MLD
• C. MLD Snooping
• D. Embedded RP
• E. DHCPv6

Answer: D

NEW QUESTION 6
Refer to the exhibit.




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

Answer: AE

Explanation:
#show ip bgp

NEW QUESTION 7
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 the224.0.1.39 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

Answer: DEF

NEW QUESTION 8
Which command set is used to configure BFD support for a BGP neighbor that is reachable through GigabitEthernet 0/0/0/0 on Cisco IOS XR?

• A. router bgp 300 bfd multiplier 2bfd minimum-interval 20neighbor 10.20.20.2remote-as 200
• B. router bgp 300 bfd multiplier 2bfd minimum-interval 20neighbor 10.20.20.2remote-as 200 bfd fast-detect
• C. bfdecho disable router bgp 300neighbor 10.20.20.2remote-as 200
• D. bfdrouter bgp 300neighbor 10.20.20.2remote-as 200
• E. interface Gi0/0/0/0ipv4 verify unicast source reachable-via rx router bgp 300bfd multiplier 2bfd minimum-interval 20neighbor 10.20.20.2remote-as 200 bfd fast-detect
• F. interface Gi0/0/0/0ipv4 verify unicast source reachable-via rx bfdinterface Gi0/0/0/0 echo disable router bgp 300bfd multiplier 2bfd minimum-interval 20neighbor 10.20.20.2remote-as 200

Answer: B

NEW QUESTION 9
Refer to the Cisco IOS-XR BGP configuration exhibit.

Identify two configuration errors. (Choose two.)

• A. The neighbor-group efg is missing the ebgp-multihop 2 configuration
• B. The ttl-security configuration command is missing the option to set the number of hops
• C. The passall route policy is wrong
• D. The route-policy passall in and route-policy passall out commands should be configured under the neighbor-group efg instead of the af-group abc
• E. The maximum-prefix 10 configuration should be configured under the af-group abc instead of the neighbor-group efg

Answer: CE

Explanation:
http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a00801 0a28a.shtml

NEW QUESTION 10
Refer to the exhibit.

R5 is configured as the RP for the PIM-SM domain for AS 1020. If R3 and R4 are correctly configured, which Cisco IOS-XE configuration should be done on R5 to configure it as a PIMv3 BSR router?

• A. ip pim send-rp-announce loopback 0 scope 16 int gi1/3 , gi 1/4ip pim sparse-mode int gi 1/1ip pim bsr-border
• B. ip pim rp-candidate loopback 0 int gi1/3 , gi 1/4ip pim sparse-mode int gi 1/1ip pim bsr-border
• C. ip pim rp-candidate loopback 0 int gi1/3 , gi 1/4ip pim sparse-mode ip pim bsr-border
• D. ip pim send-rp-announce loopback 0 scope 16 int gi1/3 , gi 1/4ip pim sparse-mode ip pim bsr-border

Answer: B

NEW QUESTION 11
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

Answer: B

NEW QUESTION 12
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)#

Answer: D

Explanation:
http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a00801 0a28a.shtml

NEW QUESTION 13
Each router (RTA, RTB, and RTC) has one iBGP adjacency with the route reflector router RTD. Router RTC has an iBGP route advertised by RTA, but the same route is missing from RTB. Thenetwork engineer verifies that route filtering does not deny the route advertisement. Which action corrects the problem?

• A. RTD(config-router)#neighbor 192.168.1.1 route-reflector-client RTD(config-router)#neighbor 192.168.1.1 description RTA RTD(config-router)#neighbor 192.168.1.2 route-reflector-client RTD(config-router)#neighbor 192.168.1.2 description RTB
• B. RTC(config-router)#neighbor 192.168.1.4 route-reflector-client RTC(config-router)#neighbor 192.168.1.4 description RTD
• C. RTA(config-router)#neighbor 192.168.1.4 route-reflector-client RTA(config-router)#neighbor 192.168.1.4 description RTDRTB(config-router)#neighbor 192.168.1.4 route-reflector-client RTB(config-router)#neighbor 192.168.1.4 description RTD
• D. RTB(config-router)#neighbor 192.168.1.3 route-reflector-client RTB(config-router)#neighbor 192.168.1.3 description RTC
• E. RTB(config-router)#neighbor 192.168.1.3 route-reflector-client RTB(config-router)#bgp cluster-id 192.168.1.2RTB(config-router)#no bgp client-to-client reflection

Answer: A

NEW QUESTION 14
A network engineer must deploy an iBGP-based cloud region configuration by means of templates to reduce the overall BGP CLI required. Which three commands represent a basic configuration for a BGP peer session template on a regular Cisco IOS instance? (Choose three.)

• A. template peer-session session-template-name
• B. remote-as as-number
• C. neighbor-family config template
• D. peer-family config template
• E. as-override
• F. timers keepalive-interval hold-time

Answer: ABF

NEW QUESTION 15
Which IPv6 mechanism occurs between a provider edge router and the customer premises equipment router to allow an ISP to automate the process of assigning a block of IPv6 addresses to a customer for use within the customer network?

• A. Router Advertisement
• B. DHCPv6 Prefix Delegation
• C. DHCPv6 Lite
• D. Stateful DHCPv6

Answer: B

Explanation:
http://www.cisco.com/en/US/tech/tk872/technologies_configuration_example09186a0080b 8a116.shtml

NEW QUESTION 16
What is enabled by default on Cisco IOS-XR routers and cannot be disabled?

• A. SSH server
• B. Multicast routing
• C. IPv4 and IPv6 CEF
• D. IPv6 routing
• E. CDP
• F. BFD

Answer: C

Explanation:
Before using the BGP policy accounting feature, you must enable BGP on the router (CEF is enabled by default).

NEW QUESTION 17
Which two statements correctly describe the BGP ttl-security feature? (Choose two.)

• A. This feature protects the BGP processes from CPU utilization-based attacks from EBGP neighbors which can be multiple hops away
• B. This feature prevents IBGP sessions with non-directly connected IBGP neighbors
• C. This feature will cause the EBGP updates from the router to be sent using a TTL of 1
• D. This feature needs to be configured on each participating BGP router
• E. This feature is used together with the ebgp-multihop command

Answer: AD

Explanation:
http://packetlife.net/blog/2009/nov/23/understanding-bgp-ttl-security/

NEW QUESTION 18
Which additional feature is provided using MLDv2 that is not available in MLDv1?

• A. Multicast Address Specific Queries
• B. Source filtering
• C. Done messages
• D. Report messages

Answer: B

Explanation:
• PIM-SSM is made possible by IGMPv3 and MLDv2. Hosts can now indicate interest in specific sources using IGMPv3 and MLDv2. SSM does not require a rendezvous point (RP) to operate.

NEW QUESTION 19
Refer to the Cisco IOS-XR show output exhibit.

Which statement is correct?

• A. The [ ] indicates the configuration has a problem
• B. The [ ] indicates the 10.1.1.1 neighbor peering session has not been established
• C. The [ ] indicates the configuration was not inherited from a group
• D. The [ ] indicates the configuration has not been committed
• E. The [ ] indicates the corresponding BGP peer configuration has a mismatch configuration

Answer: C

Explanation:
show bgp neighbors
Use the show bgp neighbors command to display information about the BGP configuration for neighbors.
•Use the configuration option to display the effective configuration for the neighbor, including any settings that have been inherited from session groups, neighbor groups, or af-groups used by this neighbor.
•Use the inheritance option to display the session groups, neighbor groups, and af-groups from which this neighbor inherits configuration settings.
The following example displays sample output from the show bgp af-group command using the configuration keyword. This example shows where each configuration item was
inherited from. The default-originate command was configured directly on this address family group (indicated by [ ]). The remove-private-as command was inherited from address family group GROUP_2, which in turn inherited from address family group GROUP_3:

NEW QUESTION 20
After configuring the tunnel interface as shown in the exhibit, no IPv6 traffic is passed over the IPv4 network.

Which additional configuration is required to pass the IPv6 traffic over the IPv4 network?

• A. Configure an IPv4 address on the tunnel0 interface
• B. Configure an IPv6 static route to send the required IPv6 traffic over the tunnel0 interface
• C. The tunnel destination should be pointing to an IPv6 address instead of an IPv4 address
• D. The tunnel0 interface IPv6 address must use the 2002:://16 prefix

Answer: B

NEW QUESTION 21
A CRS router that runs Cisco IOS XR has dual routing processors installed. Which solution should be implemented to prevent OSPF adjacency flapping if the primary routing processor fails?

• A. NSR
• B. OSPF Fast Timers
• C. OSPF RE Sync
• D. router msdp
• E. NSF

Answer: A

NEW QUESTION 22
Which two actions result when a network administrator attempts to ping an IPv6 host on the LAN? (Choose two.)

• A. ARP is used to determine the MAC address of the destination host.
• B. Neighbor Discovery is used to determine the MAC address of the destination host.
• C. Neighbor Solicitation messages are sent out by the source host to determine the data link-layer address of the destination host.
• D. Neighbor Advertisement messages are sent by the source host to announce its presence on the local link.
• E. Router Solicitation messages are sent out on a specific multicast address to request the data link-layer address of the target device.
• F. Router Solicitation messages are sent to the local router on the network segment to request data link-layer information about the destination host.

Answer: BC

NEW QUESTION 23
Refer to the exhibit.

Which statement correctly explains the bgp graceful-restart command?

• A. This command is used to enable NSR and is entered on the NSR-capable router, and also on any NSR-aware peer
• B. This command is used to enable NSF and is entered on the NSF-capable router, and also on any NSF-aware peer
• C. This command is only required on the NSF-capable routers to enable BGP graceful restart with the BGP peers
• D. This command is only required on the NSF-aware routers to enable BGP graceful restart with the BGP peers
• E. This command is only required on the NSR-capable routers to enable BGP graceful restart with the BGP peers

Answer: B

Explanation:
Graceful restart is supported in recent versions of Cisco IOS software (12.0S) and is supported in Cisco IOS XR software. Graceful restart is the mechanism by which BGP routing peers avoid changes to their forwarding paths following a switchover. If the BGP peer has received this capability, it is aware that the device sending the message is nonstop forwarding (NSF)-capable. Both the NSF-capable router and its BGP peers (NSFaware peers) need to exchange the graceful restart capability in their OPEN messages, at the time of session establishment. If both peers do not exchange the graceful restart capability, the session will not be graceful restart-capable.
If the BGP session is lost during a Route Processor (RP) switchover or BGP process restart, the NSF-aware BGP peer marks all the routes associated with the NSF-capable router as stale; however, it continues to use these routes to make forwarding decisions for a set period of time. This functionality means that no packets are lost while the newly active RP is waiting for convergence of the routing information with its BGP peers.
After a failover event occurs, the NSF-capable router reestablishes the session with the BGP peer. In establishing the new session, it sends a new graceful restart message that identifies the NSF-capable router as having restarted. At this point, the routing information is exchanged between the two BGP peers. Once this exchange is complete, the NSF- capable device uses the newly received routing information to update the RIB and the Forwarding Information Base (FIB) with the new forwarding information. The NSF-aware device uses the network information to remove stale routes from its BGP table. The BGP protocol is then fully converged.
If a BGP peer does not support the graceful restart capability, it will ignore the graceful restart capability in an OPEN message but will establish a BGP session with the NSF- capable device. This functionality will allow interoperability with non-NSF-aware BGP peers (and without NSF functionality), but the BGP session with non- NSF-aware BGP peers will not be graceful restart-capable.

NEW QUESTION 24
An engineer is providing DNS for IPv6 over a currently working IPv4 domain. Which three changes are needed to offer DNS functionality for IPv6? (Choose three.)

• A. Define a new record that stores the 128-bit IPv6 address.
• B. Expand the existing IP address record to allow for 128 bits.
• C. Define the IPv6 equivalent of the in-addr.arpa.com domain of the IPv4 PTR.
• D. Modify the in-addr.arpa.com domain of the IPv4 PTR.
• E. Change the query messages.
• F. Transport IPv6 query messages by using UDP.
• G. Transport IPv6 query messages by using TCP.

Answer: ACE

NEW QUESTION 25
Refer to the exhibit.




Which three statements regarding the BGP operations are correct? (Choose three)

• A. PE5 is the route reflector with P1 and PE6 as its client
• B. PE5 is using the IS-IS route to reach the BGP next-hop for the 172.16.66.0/24 prefix
• C. PE5 has BGP route dampening enabled
• D. The BGP session between PE5 and P1 is established using the loopback interface andnext-hop-self
• E. The BGP session between PE5 and CE5 is established using the loopback interface

Answer: ACD

NEW QUESTION 26
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