22 February, 2020

Verified Cisco 642-885 Bootcamp

Proper study guides for Abreast of the times Cisco Deploying Cisco Service Provider Advanced Routing (SPADVOUTE) certified begins with Cisco 642-885 preparation products which designed to deliver the Certified 642-885 questions by making you pass the 642-885 test at your first time. Try the free 642-885 demo right now.

Free demo questions for Cisco 642-885 Exam Dumps Below:

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Total 131 questions Full Exam Access

Question 1

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?

Some prefixes were mistagged with the no-export BGP community

Some prefixes were set with an MED of 0

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

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

Question 2

Which two statements correctly describe the RPF check when a multicast packet arrives at a router? (Choose two.)

The router looks up the source address in the unicast routing table to determine if the packet has arrived on the interface that is on the reverse path back to the source

The router looks up the destination address in the unicast routing table to determine if the packet has arrived on the interface that is on the reverse path back to the destination

If the packet has arrived on the interface leading back to the destination, the RPF check passes and the packet is forwarde

If the RPF check fails, the packet is dropped

If the packet has arrived on the interface leading back to the source, the RPF check passes and the packet is forwarde

If the RPF check fails, the packet is dropped

Question 3

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

This feature protects the BGP processes from CPU utilization-based attacks from EBGP neighbors which can be multiple hops away

This feature prevents IBGP sessions with non-directly connected IBGP neighbors

This feature will cause the EBGP updates from the router to be sent using a TTL of 1

This feature needs to be configured on each participating BGP router

This feature is used together with the ebgp-multihop command

Question 4

Refer to the exhibit.
642-885 dumps exhibit

Which option is the function of designing a hub and spoke confederation?

allows transit backbone area 66000 to be a blackhole for non-transit ASs

reduces the iBGP mesh, iBGP mesh will be in sub non-transit ASs

increases eBGP sessions between the confederation sub ASs

allows transit backbone area and non-transit ASs to run the same IGP

Question 5

Which configuration for implementing 6PE on an IS-IS-enabled Cisco IOS XR router is correct?

interface GigabitEthernet0/0/0/0 ipv6 address 2001:DB8:DD11::1/64 router isis ipv6-tunnet 49.0000.0000.00010.00address-family ipv6 unicast single-topologyredistribute bgp 200interface GigabitEthernet0/0/0/0 address-family ipv6 unicast router bgp 200bgp router-id 209.165.202.129 address-family ipv4 unicast address-family ipv6 unicast redistribute isis ipv6-tun neighbor 209.165.202.130remote-as 200address-family ipv4 unicast address-family ipv6 labeled-unicast

interface GigabitEthernet0/0/0/0 ipv6 address 2001:DB8:DD11::1/64 router isis ipv6-tunnet 49.0000.0000.00010.00address-family ipv6 unicast single-topologyrouter bgp 200bgp router-id 209.165.202.129 address-family ipv4 unicast address-family ipv6 unicast redistribute isis ipv6-tun neighbor 209.165.202.130remote-as 200address-family ipv4 unicast address-family ipv6 labeled-unicast

interface GigabitEthernet0/0/0/0 ipv6 address 2001:DB8:DD11::1/64 router isis ipv6-tunnet 49.0000.0000.00010.00address-family ipv6 unicast single-topologyinterface GigabitEthernet0/0/0/0 address-family ipv6 unicast router bgp 200bgp router-id 209.165.202.129 address-family ipv4 unicast address-family ipv6 unicast redistribute staticneighbor 209.165.202.130remote-as 200address-family ipv4 unicast address-family ipv6 labeled-unicast

interface GigabitEthernet0/0/0/0 ipv6 address 2001:DB8:DD11::1/64 router isis ipv6-tunnet 49.0000.0000.00010.00address-family ipv6 unicast single-topologyinterface GigabitEthernet0/0/0/0 address-family ipv6 unicast router bgp 200bgp router-id 209.165.202.129 address-family ipv4 unicast address-family ipv6 unicastredistribute connected redistribute isis ipv6-tun neighbor 209.165.202.130remote-as 200address-family ipv4 unicast address-family ipv6 labeled-unicast

interface GigabitEthernet0/0/0/0 ipv6 address 2001:DB8:DD11::1/64 router isis ipv6-tunnet 49.0000.0000.00010.00address-family ipv6 unicast single-topologyinterface GigabitEthernet0/0/0/0 address-family ipv6 unicast router bgp 200bgp router-id 209.165.202.129 address-family ipv4 unicast address-family ipv6 unicast redistribute connected redistribute isis ipv6-tun neighbor 209.165.202.130remote-as 200address-family ipv4 unicast

Question 6

Which four operations are components of MSDP in interdomain multicast setup? (Choose four.)

Multiple domains can have a single statically defined RP.

RPs interconnect between domains with UDP connections to pass source active messages.

RPs interconnect between domains with TCP connections to pass source active messages.

RPs send source active messages for internal sources to MSDP peers.

Source active messages are Peer-RPF checked before accepting or forwarding.

RPs learn about external sources via source active messages and may trigger (S,G) joins on behalf of local receivers.

MSDP connections typically parallel PIM-SM connections.

Question 7

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

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

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

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

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

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

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

My answer: -

Reference answer: AD

Reference analysis:

Auto-RP
Automatic route processing (Auto-RP) is a feature that automates the distribution of group- to-RP mappings in a PIM network. This feature has these benefits:
It is easy to use multiple RPs within a network to serve different group ranges. It allows load splitting among different RPs.
It facilitates the arrangement of RPs according to the location of group participants.
It avoids inconsistent, manual RP configurations that might cause connectivity problems. Multiple RPs can be used to serve different group ranges or to serve as hot backups for each other. To ensure that Auto-RP functions, configure routers as candidate RPs so that they can announce their interest in operating as an RP for certain group ranges. Additionally, a router must be designated as an RP-mapping agent that receives the RP- announcement messages from the candidate RPs, and arbitrates conflicts. The RPmapping agent sends the consistent group-to-RP mappings to all remaining routers. Thus, all routers automatically determine which RP to use for the groups they support auto- rp candidate-rp
To configure a router as a Protocol Independent Multicast (PIM) rendezvous point (RP) candidate that sends messages to the well-known CISCO-RP-ANNOUNCE multicast group
(224.0.1.39), use the auto-rp candidaterp command in PIM configuration mode. To return to the default behavior, use the no form of this command. auto-rp candidate-rp type interface-path-id scope ttl-value [ group-list access-listname ] [ interval seconds ] [bidir] no auto-rp candidate-rp type interface-path-id scope ttl-value [ group-list access-listname] [ interval seconds ] [bidir]

Question 8

Which informationdoes the multicast supported router need to forward the multicast traffic over the source or shared tree?

source address

multicast address

destination address

mGRE headers

MDT Data

Question 9

DRAG DROP

Solution:
The amount of time for the penalty to decrease to one-half of its current value - 60 Suppress a route when its penalty exceeds this value - 2400
If a flapping route penalty decreases and falls below this value , the route is unsuppressed
- 600
The maximum time a route can be suppressed – 240
642-885 dumps exhibit

SO bgp dampening 60 600 2400 240 is:
60 half life
600 reuse
2400 suppress
240 max-suppress-time

Does this meet the goal?

Yes

Question 10

R1 is designated as the PIM RP within the SP core. Which two configuration parameters must be used to enable and activate R1 as the BSR and RP for the core environment? (Choose two.)

ip pim send-rp-announce loopback0 scope 16

ip pim bsr-candidate loopback0

ip pim send-rp-discovery loopback0 scope 16

ip pim rp-candidate loopback0

ip pim send-RP-announce loopback0 scope 16 group-list 1

Question 11

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?

NSR

OSPF Fast Timers

OSPF RE Sync

router msdp

NSF

Question 12

When verifying multicast configurations and operations on Cisco IOS-XR routers, which two statements regarding show commands are correct? (Choose two.)

Use the show route ipv4 multicast command to display the incoming and outgoing interface lists for each of the joined multicast groups

Use the show pim rpf command to display the RPF information for the RP or for the multicast source

Use the show mrib route command to display the (*, G) and (S, G) states information on the router

Use the show mrib route command to display the configured static multicast routes

Question 13

Refer to the configuration exhibit, taken from a Cisco IOS-XR router.
642-885 dumps exhibit

Which configuration change is required to properly enable this router as the signaling router for implementing source-based RTBH filtering?

Set community (no-export) in the route policy

Pass in the route policy

Set local-preference 1000 in the route policy

The 192.0.2.1/32 static route should be tagged as 666 (tag 666)

Question 14

Which difference occurs between intradomain and interdomain routing technology?

PIM is used in intradomain routing technology and uses reverse path forwarding mechanism to implement optimize multicast data forwarding.

MSDP is used in intradomain routing technology to discover the multicast source.

Interdomain routing technology uses MSDP and M-BGP for exchanging multicast routing information.

RP is not needed in intradomain routing technology, but RP is needed in interdomain routing technology to receive multicast traffic.

Question 15

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?

RP/0/RSP0/CPU0:P2(config-bgp)#

RP/0/RSP0/CPU0:P2(config-bgp-af)#

RP/0/RSP0/CPU0:P2(config-bgp-nbr)#

RP/0/RSP0/CPU0:P2(config-bgp-nbr-af)#

Question 16

Which statement is correct regarding MP-BGP?

MP-BGP can indicate whether an advertised prefix (NLRI) is to be used for unicast routing, multicast RPF checks or for both using different SAFIs.

MP-BGP uses a single BGP table to maintain all the unicast prefixes for unicast forwarding and all the unicast prefixes for RPF checks.

MP-BGP can be used to propagate multicast state information, which eliminates the need to use PIM for building the multicast distribution trees.

MP-BGP enables BGP to carry IP multicast routes used by MSDP to build the multicast distribution trees.

My answer: -

Reference answer: A

Reference analysis:

Protocol Independent Multicast
Protocol Independent Multicast (PIM) is a routing protocol designed to send and receive multicast routing updates. Proper operation of multicast depends on knowing the unicast paths towards a source or an RP. PIM relies on unicast routing protocols to derive this reverse-path forwarding (RPF) information. As the name PIM implies, it functions independently of the unicast protocols being used. PIM relies on the Routing Information Base (RIB) for RPF information. If the multicast subsequent address family identifier (SAFI) is configured for Border Gateway Protocol (BGP), or if multicast intact is configured, a separate multicast unicast RIB is created and populated with the BGP multicast SAFI routes, the intact information, and any IGP information in the unicast RIB. Otherwise, PIM gets information directly from the unicast SAFI RIB. Both multicast unicast and unicast databases are outside of the scope of PIM.
The Cisco IOS XR implementation of PIM is based on RFC 4601 Protocol Independent Multicast - Sparse
Mode (PIM-SM): Protocol Specification. For more information, see RFC 4601 and the Protocol Independent Multicast (PIM): Motivation and Architecture Internet Engineering Task Force (IETF) Internet draft

Question 17

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.)

template peer-session session-template-name

remote-as as-number

neighbor-family config template

peer-family config template

as-override

timers keepalive-interval hold-time

Question 18

A network engineer is working for an ISP and a current eBGP customer requests to enable the BGP TTL security feature. The engineer sees from the current established BGP session that the eBGP peer is directly connected and the ebgp-multihop feature is already in use with a value of one. Which two actions are needed on the Cisco IOS XR router to accomplish the task? (Choose two.)

Configure the neighbor with the command ttl-security.

Disable the eBGP-multihop feature.

Clear the BGP session for the configuration change to take effect.

Enable the BGP TTL security and the BGP peer resets automatically for the change to take effect.

Configure the neighbor with the command ttl-security 254.

Question 19

Which four statements are correct regarding MSDP configurations and operations? (Choose four.)

The MSDP peers are also typically the RPs in respective routing domains.

SA messages are flooded to all other MSDP peers without any restrictions

On Cisco IOS, IOS-XE, and IOS-XR, the router can be configured to cache the SA messages to reduce the join latency

SA messages are used to advertise active sources in a domain

MSDP establishes neighbor relationships with other MSDP peers using TCP port 639

MSDP peerings on Cisco IOS, IOS-XE, and IOS-XR support MD5 or SHA1 authentication

Question 20

Which multicast routing protocol is used to forward multicast data along the optimal path from source to receivers?

PIM DM

PIM Bi-Dir

PIM SM

SSM

IGMP

MSDP

Question 21

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

The retry interval

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

The minimum interval between packets accepted from the BFD peers

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

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

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Total 131 questions Full Exam Access