Review Questions

1:	Give several reasons why replicated unicast is not a practical substitution for true multicast in a large network. ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
2:	What range of addresses is reserved for IP multicast? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
3:	How many subnets can be created from a single Class D prefix? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
4:	In what way do routers treat packets with destination addresses in the range 224.0.0.1 “224.0.0.255 differently from other multicast addresses? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
5:	Write the Ethernet MAC addresses that correspond to the following IP addresses: 239.187.3.201 224.18.50.1 224.0.1.87 ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
6:	What multicast IP address or addresses are represented by the MAC address 0100.5E06.2D54? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
7:	Why is Token Ring a poor medium for delivering multicast packets? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
8:	What is join latency? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
9:	What is leave latency? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
10:	What is a multicast DR (or querier)? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
11:	What device sends IGMP Query messages? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
12:	What device sends IGMP Membership Report messages? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
13:	How is an IGMP Membership Report message used? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
14:	What is the functional difference between a General IGMP Query and a Group-Specific IGMP Query? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
15:	Is IGMPv2 compatible with IGMPv1? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
16:	What IP protocol number signifies IGMP? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
17:	What is the purpose of the Cisco Group Membership Protocol (CGMP)? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
18:	What is the advantage of using IP Snooping rather than CGMP? What is the possible disadvantage ? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
19:	What devices send CGMP messages: routers, Ethernet switches, or both? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
20:	What is Reverse Path Forwarding? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
21:	How many hosts constitute a dense topology, and how many hosts constitute a sparse topology? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
22:	What is the primary advantage of explicit joins over implicit joins? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
23:	What is the primary structural difference between a source-based multicast tree and a shared multicast tree? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
24:	What is multicast scoping? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
25:	What are the two methods of IP multicast scoping? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
26:	From the perspective of a multicast router, what is meant by upstream and what is meant by downstream? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
27:	What is an RPF check? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
28:	What is a prune? What is a graft ? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
29:	What is a prune lifetime? What happens when a prune lifetime expires ? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
30:	What is a route dependency? How does DVMRP signal a route dependency? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
31:	Is DVMRP a dense-mode protocol or a sparse-mode protocol? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
32:	Is MOSPF a dense-mode protocol or a sparse-mode protocol? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
33:	What is the name and type number of the LSA used exclusively by MOSPF? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
34:	Can an MOSPF router establish an adjacency with an OSPF router that does not support MOSPF? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
35:	Define the following MOSPF router types: Interarea multicast forwarder Inter-AS multicast forwarder Wildcard multicast receiver ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
36:	Is CBT a dense-mode protocol or a sparse-mode protocol? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
37:	What are a CBT parent router and a CBT child router? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
38:	Describe the two ways a CBT DR can deliver packets from a source to the core and the circumstances under which each method is used. ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
39:	What is a PIM prune override? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
40:	What is a PIM forwarder? How is a forwarder selected? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
41:	What criteria does PIM use to select a DR? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
42:	What is a PIM SPT? What is a PIM RPT? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
43:	What two mechanisms are available for Cisco routers to automatically discover PIM-SM RPs? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
44:	Of the mechanisms in Question 43, which should be used in multivendor router topologies? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
45:	What is a C-RP? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
46:	What is a BSR? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
47:	What is an RP mapping agent? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
48:	What is the difference between an (S, G) mroute entry and a (*, G) mroute entry? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
49:	What is the major drawback with a bidirectional CBT tree between the source and core, as opposed to a PIM-SM unidirectional tree from the RP to the source? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
50:	What is PIM-SM source registration? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
51:	When does a Cisco router switch from a PIM-SM RPT to an SPT? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________