The second question was:
* Which router (A or B) is going to send the queries to the LAN to determine if there are any more active listeners?
Answer: Obviously, only one of the routers should query the LAN to determine if there are any listening hosts. IGMP determines which router should send the queries on to the segment using the IP addresses. If R2 sends it’s query first, R1 will hear the query and determine that R2 should be the active querier on the segment because R2’s IP address is lower. The opposite could happen, and R1 might be active first, send the query and then R2 could come alive. In this case, R2 would see that it has a lower IP address and send it’s query. R1 would then hear the query from a lower IP address and reliquesh it’s duties to R2. So what happens if R2 fails? R1 has a timer called the ‘query timeout’. If that time runs out and R1 hasn’t heard a query from R2, it takes control and starts to query.