What are three important changes to IGMPv1 that were implemented in IGMPv2? (Choose three.)
- team-specific queries
- leave-group message
- group-specific queries
- stop-group message
- membership reports
- querier election mechanism
Explanation: IGMPv2 addressed several limitations found in IGMPv1 by introducing the following key features:
- Group-specific queries: While IGMPv1 used general queries sent to the all-hosts address (224.0.0.1), IGMPv2 added the ability for a router to query a single specific multicast group. This optimization allows the router to quickly determine if any members remain in a specific group without querying every group on the segment.
- Leave-group message: Unlike IGMPv1, which relied on timeouts to determine when a host had left a group, IGMPv2 allows hosts to actively send a leave-group message. This drastically reduces leave latency, especially when the host leaving is the last member of that group on the segment.
- Querier election mechanism: IGMPv2 implemented a standardized method to elect a single querier when multiple routers exist on the same segment. The router with the lowest unicast IP address is elected as the querier, whereas IGMPv1 lacked a formal election process.
Additionally, IGMPv2 introduced a query-interval response time to control the "burstiness" of membership reports by specifying how much time members have to respond to a query.
Related exam: Modules 8 – 13: Checkpoint Exam: Network Routing Answers (CCNP ENCOR v9)
