CCNP BCMSN Exam Cram 2 (Exam Cram 642-811)

Question 1

With a _________, each destination receives a separate packet.

  • A. Unicast

  • B. Broadcast

  • C. Multicast

A1:

Answer A is correct. With a unicast, each destination receives a separate packet. With a broadcast or multicast, each destination receives the same packet, making answers B and C incorrect.

Question 2

Which multicast address is used to send information to all RPs in a subnet?

  • A. 224.0.0.1

  • B. 224.0.0.2

  • C. 224.0.0.5

  • D. 224.0.0.6

A2:

Answer B is correct. When information needs to be sent to all RPs on a segment, use 224.0.0.2 as a multicast address. 224.0.0.1 is the all-host group (all devices), making answer A incorrect. Answers C and D are incorrect because OSPF uses these addresses.

Question 3

What protocol is used by an RP to discover which end stations want to receive multicast traffic?

  • A. PIM

  • B. CGMP

  • C. ICMP

  • D. IGMP

A3:

Answer D is correct. IGMP is used to determine what clients are participating in multicast groups. Answer A is incorrect because PIM is used to route multicast traffic. Answer B is incorrect because CGMP is used to help switches learn locations of multicast clients. Answer C is incorrect because this is used to test IP connections.

Question 4

In IGMPv2, the router with the _________ IP address is elected as the active querier.

  • A. Lowest

  • B. Highest

A4:

Answer A is correct. The IGMPv2 active querier is elected based on the RP with the lowest IP address. Because it is the lowest, answer B is incorrect.

Question 5

Which version of IGMP allows a client to determine which sources can be used for multicast feeds?

  • A. v1

  • B. v2

  • C. v3

  • D. v2 and v3

A5:

Answer C is correct. IGMPv3 supports INCLUDE and EXCLUDE report messages, where an EXCLUDE report message can be used to specify the source addresses wanted for a specific multicast feed. Therefore, answers A, B, and D are incorrect.

Question 6

Which distribution tree uses a rendezvous point to build a single-tree structure for multicast routing?

  • A. PIM

  • B. Source

  • C. Shared

  • D. CGMP

A6:

Answer C is correct. Shared distribution trees have a rendezvous point that's used to build a single-tree instance for all multicast traffic. Answer A is incorrect because PIM is used to route multicast traffic it isn't a tree structure. Answer B is incorrect because source-based trees have a separate tree structure for each multicast feed. Answer D is incorrect because CGMP is used by switches to learn about participating multicast clients.

Question 7

The president of your company will be making a live presentation on Friday at 3 p.m. and every employee needs to see it. In what mode would you configure PIM for this multicast feed?

  • A. Sparse

  • B. Dense

A7:

Answer B is correct. Use dense mode if most clients need to see the multicast feed. Sparse mode is used when only a few, geographically dispersed clients need to see a feed, making answer A incorrect.

Question 8

PIM-DM uses ______ to build its distribution tree.

  • A. Spanning tree

  • B. IGMP

  • C. Reverse path forwarding

  • D. Rendezvous point

A8:

Answer C is correct. Reverse path forwarding is used to build PIM-DM's tree. Answer A is incorrect because spanning tree is used by switches to remove Layer 2 loops. Answer B is incorrect because IGMP is used to discover multicast participating clients. Answer D is incorrect because a rendezvous point is used in PIM-SM.

Question 9

Which method is recommended to control the switching of multicast traffic?

  • A. VLANs

  • B. IGMP snooping

  • C. Static multicast CAM entries

  • D. CGMP

A9:

Answer D is correct. CGMP is recommended to intelligently switch multicast traffic. VLANs and static multicast CAM entries don't scale well, making answers A and C incorrect. IGMP snooping has performance problems on lower-end switches, making answer B incorrect.

Question 10

If you have two multicast feeds, one where everyone needs to see the multicast feed and the other where only a handful need to see it, which PIM mode would you use with the ip pim Interface command?

  • A. dense-mode

  • B. sparse-mode

  • C. sparse-dense-mode

  • D. spare-and-dense-mode

A10:

Answer C is correct. When you have different multicast feeds with different user needs, use the ip pim sparse-dense-mode command. Answer A is incorrect because dense-mode should be used only when all devices need to see all multicast feeds. Answer B is incorrect because sparse-mode should be used when only a small number of users need to see all multicast feeds. Answer D is incorrect because it is a nonexistent parameter.

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