[Free] Download Latest (March 2016) Cisco 642-885 Real Exam 11-20

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QUESTION 11

On Cisco IOS-XR, which BGP configuration group allows you to define address-family independent commands and address-family dependent commands for each address family?

 

A.

neighbor-group

B.

session-group

C.

af-group

D.

peer-group

 

Correct Answer: A

Explanation:

Commands relating to a peer group found in Cisco IOS Release 12.2 have been removed from Cisco IOS XR software. Instead, the af-group, session-group, and neighbor-group configuration commands are added to support the neighbor in Cisco IOS XR software:

 

The af-group command is used to group address family-specific neighbor commands within an IPv4 or IPv6 address family. Neighbors that have the same address family configuration are able to use the address family group name for their address family- specific configuration. A neighbor inherits the configuration from an address family group by way of the use command. If a neighbor is configured to use an address family group, the neighbor will (by default) inherit the entire configuration from the address family group. However, a neighbor will not inherit all ofthe configuration from the address family group if items are explicitly configured for the neighbor.

 

The session-group command allows you to create a session group from which neighbors can inherit address family-independent configuration. A neighbor inherits the configuration from a session group by way of the use command. If a neighbor is configured to use a session group, the neighbor (by default) inherits the session group’s entire configuration. A neighbor does not inherit all the configuration from a session group if a configuration is done directly on that neighbor.

 

The neighbor-group command helps you apply the same configuration to one or more neighbors. Neighbor groups can include session groups and address family groups. This additional flexibility can create a complete configuration for a neighbor. Once a neighbor group is configured, each neighbor can inherit the configuration through the use command. If a neighbor is configured to use a neighbor group, the neighbor (by default) inherits the neighbor group’s entire BGP configuration.

 

However, a neighbor will not inherit all of the configuration from the neighbor group if items are explicitly configured for the neighbor. In addition, some part of the neighbor group’s configuration could be hidden if a session group or address family group was also being used

 

 

QUESTION 12

Refer to the exhibit. Which option is the function of designing a hub and spoke confederation?

 

clip_image002

 

A.

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

B.

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

C.

increases eBGP sessions between the confederation sub ASs

D.

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

 

Correct Answer: B

QUESTION 13

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

 

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C.

A.

Multiple domains can have a single statically defined RP.

B.

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

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

D.

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

E.

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

F.

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

G.

MSDP connections typically parallel PIM-SM connections.

 

Correct Answer: CDEF

 

 

QUESTION 14

When implementing high-availability stateful switchover BGP ro
uting, 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

 

Correct Answer: A

 

 

QUESTION 15

Which protocol can be used to secure multicast in a group multicast solution where group key management is needed for secure key exchange?

 

A.

DOI

B.

ISAKMP

C.

GDOI

D.

IPsec

 

Correct Answer: C

 

 

QUESTION 16

Which two functions are supported for BGP extension MP-BGP for IP multicasting? (Choose two.)

 

A.

A network can support incongruent unicast and multicast topologies.

B.

A network can support congruent unicast and multicast topologies.

C.

MP-BGP is an enhanced BGP that carries routing information for multiple network layer protocols and IP multicast routes.

D.

MP-BGP carries single sets of routes for unicast routing and multicast routing.

E.

MP-BGP is useful when a link dedicated to multicast and unicast traffic is desired.

Correct Answer: AC

 

 

QUESTION 17

When implementing interdomain multicast routing, which mechanism can be used to advertise multicast sources in one domain to the other domains, allowing the RPs to build interdomain multicast distribution trees?

 

A.

Multiprotocol BGP

B.

PIM

C.

MSDP

D.

Auto RP

E.

BSR

F.

MLD

 

Correct Answer: C

Explanation:

Multicast Source Discovery Protocol

Multicast Source Discovery Protocol (MSDP) is a mechanism to connect multiple PIM sparse-mode domains.

MSDP allows multicast sources for a group to be known to all rendezvous point(s) (RPs) in different domains.

Each PIM-SM domain uses its own RPs and need not depend on RPs in other domains. An RP in a PIM-SM domain has MSDP peering relationships with MSDP-enabled routers in other domains.

Each peering relationship occurs over a TCP connection, which is maintained by the underlying routing system.

MSDP speakers exchange messages called Source Active (SA) messages. When an RP learns about a local active source, typically through a PIM register message, the MSDP process encapsulates the register in an SA message and forwards the information to its peers. The message contains the source and group information for the multicast flow, as well as any encapsulated data. If a neighboring RP has local joiners for the multicast group, the RP installs the S, G route, forwards the encapsulated data contained in the SA message, and sends PIM joins back towards the source. This process describes how a multicast path can be built between domains.

 

 

QUESTION 18

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

 

Correct Answer: A

 

 

 

 

 

 

 

 

 

QUESTION 19

Refer to the Cisco IOS-XR show output exhibit. Which two statements are correct? (Choose two.)

 

clip_image004

 

A.

The RPF neighbor 192.168.11.1 is the path towards the RP for the 224.1.1.1 multicast group

B.

The RP for the 224.1.1.1 multicast group is reachable over the Gi0/0/0/0 interface

C.

This router is the RP for the 224.1.1.1 multicast group

D.

Incoming 224.1.1.1 multicast group traffic will be sent out through the Gi0/0/0/0 interface

E.

Incoming 224.1.1.1 multicast group traffic will be sent out through the Gi0/0/0/2 interface

 

Correct Answer: AD

 

 

QUESTION 20

Which type of DNS record is used for IPv6 forward lookups?

 

A.

A records

B.

AAAA records

C.

PTR records

D.

MX records

 

Correct Answer: B

 

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