Multicast CCIE-ENTERPRISE-INFRASTRUCTURE Practice Questions (Page 7)

Questions 31–35

1. 31expert · hard

   A network engineer is designing a PIM-SM network for a video conferencing application. The application has many short-lived multicast sessions. The engineer wants to minimize the state in the core routers. Which design is most appropriate?

   • AUse PIM-DM to flood and prune, which minimizes state.
   • BUse a shared tree with a high SPT threshold to keep traffic on the shared tree.
   • CUse a static RP to reduce RP discovery overhead.
   • DUse a shared tree with a low SPT threshold to switch to SPT quickly.
   Reveal Solution Discussion Select an answer first
2. 32application · medium

   A network engineer is troubleshooting multicast forwarding on a router that runs OSPF. Multicast packets from source 192.168.1.10 arrive on interface GigabitEthernet0/1, but the router drops them. The unicast route to 192.168.1.10 points to GigabitEthernet0/2. What is the most likely cause of the drops?

   • AThe multicast group is not registered with the RP.
   • BThe RPF check fails because the incoming interface does not match the unicast reverse path.
   • CIGMP snooping is disabled on the router.
   • DPIM is not enabled on GigabitEthernet0/1.
   Reveal Solution Discussion Select an answer first
4. 33expert · hard

   A multicast router has two equal-cost paths to the source network. The router receives a multicast packet on one of the paths. How does the RPF check handle this situation?

   • AThe RPF check passes if the packet arrives on any of the equal-cost paths.
   • BThe router performs a per-packet load balance and only accepts packets on the first path.
   • CThe router uses the path with the lowest IP address for the RPF check.
   • DThe RPF check fails because there is no single best path.
   Reveal Solution Discussion Select an answer first
5. 34application · medium

   A small campus network uses PIM-DM for a live video distribution system. The network has redundant links between routers. After a multicast source begins transmitting, duplicate packets are observed on some segments. What mechanism in PIM-DM resolves this duplication?

   • APIM assert messages elect a single forwarder on a multi-access network.
   • BThe RPF check automatically prunes the redundant link.
   • CPIM-DM uses a designated router election to select one path.
   • DIGMP snooping filters duplicate packets on the access layer.
   Reveal Solution Discussion Select an answer first
6. 35application · medium

   A service provider is deploying a new multicast service using PIM-SM. They want receivers to initially join a shared tree to reduce state in the core, but they also want to optimize the path for high-bandwidth streams after a threshold is exceeded. Which configuration should be used?

   • AUse Auto-RP to automatically select the RP and rely on that for path optimization.
   • BConfigure PIM-SM with an RP and enable the last-hop router to switch to the shortest-path tree (SPT) when traffic exceeds a threshold.
   • CConfigure static RP but disable SPT switchover to keep all traffic on the shared tree.
   • DUse PIM-DM to build the tree from the source directly.
   Reveal Solution Discussion Select an answer first