[Free] Download Latest (March 2016) Cisco 642-885 Real Exam 41-50

Ensurepass

QUESTION 41

Refer to the exhibit. Which configuration ensures that RR2 does not send the same updates to PE2 that RR1 learns via PE1?

 

clip_image002

 

A.

RR1 and RR2 should have different router IDs.

B.

RR1 and RR2 should have different originator IDs.

C.

RR1 and RR2 should have the same router IDs.

D.

RR1 and RR2 should have the same cluster IDs.

 

Correct Answer: D

 

 

QUESTION 42

What must occur before an (S,G) entry can be populated in the multicast routing table?

 

A.

The (*,G) entry must have timed out

B.

The (*,G) entry OIL must be null

C.

The router must be directly connected to the multicast source

D.

The parent (*,G) entry must be created first

 

Correct Answer: D

 

 

&n
bsp;

QUESTION 43

In which four ways does DHCPv6 differ from DHCPv4? (Choose four.)

 

A.

DHCPv6 uses the same message types as DHCPv4.

B.

DHCPv4 functions without external protocols.

C.

A host discovers a DHCPv6 server by using a DHCP Discover packet.

D.

A hosts discovers a DHCPv6 server by using a DHCP Solicit packet.

E.

A DHCPv6 server replies with a DHCP Offer packet.

F.

A DHCP server replies with a DHCP Advertise message.

G.

An IPv6 host can request multiple addresses at the same time from a DHCPv6 server.

H.

An IPv6 host can request only one IP address at a time from a DHCPv6 server.

 

Correct Answer: BDFG

 

 

QUESTION 44

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)#

 

Correct Answer: D

Explanation:

http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a008010a28a.shtml

 

 

QUESTION 45

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

 

Correct Answer: C

 

 

QUESTION 46

When enabling interdomain multicast routing, which two statements are correct? (Choose two.)

 

A.

Multiprotocol BGP is used instead of PIM SM to build the intradomain and interdomain multicast distribution trees

B.

Use MSDP to enable the RPs from different domains to exchange information about active multicast sources

C.

MSDP SA packets are sent between the multiprotocol BGP peers

D.

Noncongruent unicast and multicast topologies can be supported using multiprotocol BGP

 

Correct Answer: BD

Explanation:

http://prakashkalsaria.wordpress.com/2010/08/11/mbgp-msdp/

 

MSDP In the PIM-SM model, multicast sources and receivers must register with their local RP. Actually, the router closest to the sources or receivers registers with the RP, but the key point to note is that the RP knows about all the sources and receivers for any particular group. RPs in other domains have no way of knowing about sources located in other domains. MSDP is an elegant way to solve this problem.

 

MSDP is a mechanism that allows RPs to share information about active sources. RPs know about the receivers in their local domain. When RPs in remote domains hear about the active sources, they can pass on that information to their local receivers and multicast data can then be forwarded between the domains. A useful feature of MSDP is that it allows each domain to maintain an independent RP that does not rely on other domains, but it does enable RPs to forward traffic between domains. PIM-SM is used to forward the traffic between the multicast domains.

 

The RP in each domain establishes an MSDP peering session using a TCP connection with the RPs in other domains or with border routers leading to the other domains. When the RP learns about a new multicast source within its own domain (through the normal PIM register mechanism), the RP encapsulates the first data packet in a Source-Active (SA) message and sends the SA to all MSDP peers. The SA is forwarded by each receiving peer using a modified RPF check, until the SA reaches every MSDP router in the interconnected networks–theoretically the entire multicast internet. If the receiving MSDP peer is an RP, and the RP has a (*, G) entry for the group in the SA (there is an interested receiver), the RP creates (S, G) state for the source and joins to the shortest path tree for the source. The encapsulated data is decapsulated and forwarded down the shared tree of that RP. When the packet is received by the last hop router of the receiver, the last hop router also may join the shortest path tree to the source. The MSDP speaker periodically sends SAs that include all sources within the own domain of the RP

 

http://www.cisco.com/en/US/docs/ios_xr_sw/iosxr_r3.2/routing/configuration/guide/rc32bgp.html

 

Multiprotocol BGP

Multiprotocol BGP is an enhanced BGP that carries routing information for multiple network layer protocols and IP multicast routes. BGP carries two sets of routes, one set for unicast routing and one set for multicast routing.

 

The routes associated with multicast routing are used by the Protocol Independent Multicast (PIM) feature to build data distribution trees. Multiprotocol BGP is useful when you want a link dedicated to multicast traffic, perhaps to limit which resources are used for which traffic. Multiprotocol BGP allows you to have a unicast routing topology different from a multicast routing topology providing more control over your network and resources.

In BGP, the only way to perform interdomain multicast routing was to use the BGP infrastructure that was in place for unicast routing. Perhaps you want all multicast traffic exchanged at one network access point (NAP).

If those routers were not multicast capable, or there were differing policies for which you wanted multicast traffic to flow, multicast routing could not be supported without multiprotocol BGP.

Note It is possible to configure BGP peers that exchange both unicast and multicast network layer reachability information (NLRI), but you cannot connect multiprotocol BGP clouds with a BGP cloud. That is, you cannot redistribute multiprotocol BGP routes into BGP.

 

clip_image003

clip_image004

 

 

 

 

 

 

QUESTION 47

Which two specific characteristics categorize traceroute in an IPv6 routing environment? (Choose two.)

 

A.

Traceroute can show the path to reach any destination IPv6 address.

B.

Traceroute returns an error for a link-local IPv6 address.

C.

Traceroute is based on ICMPv6 Type 1 (Destination Unreachable) reply packets to determine the network path.

D.

Traceroute is based on ICMPv6 Type 3 (Time Exceeded) reply packets to determine the network path.

E.

Traceroute is based on ICMPv6 Type 2 (Packet Too Big) reply packets to determine the network path.

F.

Traceroute for IPv6 implements a backwards compatibility option to provide a detailed report in environments running dual-stack.

 

Correct Answer: AD

 

 

QUESTION 48

Which multicast implementation is preferred for traffic that is required by a small number of receivers across a large distributed network?

 

A.

DVMRP

B.

PIM-DM

C.

PIM-SM

D.

IGMP

 

Correct Answer: C

 

 

QUESTION 49

Refer to the exhibit. Which configuration is missing to complete the configuration task of enabling BFD with the 192.168.1.1 EBGP peer?

 

clip_image006

 

A.

bfd fast-detect also needs to be enabled globally under router bgp 64500

RP/0/RSP0/CPU0:P1(config-bgp)#bfd fast-detect

B.

bfd fast-detect also needs to be enabled for the address-family under address-family

ipv4 unicast

RP/0/RSP0/CPU0:P1(config-bgp-af)#bfd fast-detect

C.

bfd fast-detect also needs to be enabled for the 192.168.1.1 neighbor under neighbor 192.168.1.1

RP/0/RSP0/CPU0:P1(config-bgp-nbr)#bfd fast-detect

D.

bfd fast-detect also needs to be enabled for the 192.168.1.1 neighbor address-family under neighbor 192.168.1.1 address-family ipv4 unicast

RP/0/RSP0/CPU0:P1(config-bgp-nbr-af)#bfd fast-detect

E.

bfd fast-detect also needs to be enabled globally on the router

RP/0/RSP0/CPU0:P1(config)#bfd fast-detect

 

Correct Answer: C

 

 

QUESTION 50

A service providerrequests more details about the recent Inter-AS MPLS VPN Option B configuration that was recently deployed. Consider this configuration:

 

router bgp 3717

 

address-family vpnv4 unicast

 

retain route-target all

 

commit

 

!

 

Which option describes why this particular command is needed?

 

A.

The ASBRcan have many working customer VRFs, so this configuration ensures the coexistence of all the route-target extended communities that belong to the all ASBR- terminated customer VRFs.

B.

When implementing the Inter-AS Option B MPLS VPN solution, all the route targets that are transmitted over the Inter-AS links need an ASBR local database to forward the customer traffic correctly.

C.

The Inter-AS Option B design implements VPNv4 communication over the Inter-AS link, hence the requirement for a route-target association for each customer VPN connected across two or more ASs.

D.

In the Inter-AS Option B design, no local VRF is maintained on the ASBR routers,so the default behavior of the operating system is to deny any route-target extended community that is encoded in the incoming iBGP updates. This configuration permits VPNv4 communication by accepting the iBGP updates even if no route targets are configured locally.

 

Correct Answer: D

 

Free VCE & PDF File for Cisco 642-885 Real Exam

Instant Access to Free VCE Files: CCNA | CCNP | CCIE …
Instant Access to Free PDF Files: CCNA | CCNP | CCIE …

Comments are closed.