ZyXEL Communications ES 3500 Series Troubleshooting Manual page 42

Identify the multicast clients, multicast servers, and multicast
stream with issue.
There are three main factors to consider when dealing with multicast:
a. Which multicast clients are affected?
b. Where is the multicast server located? Server should be directly connected to
the IGMP querier.
c. Which multicast addresses being streamed have this issue?
Once you have confirmed these three information, go to step 5.
Identify which switch is the IGMP querier.
In this example, Switch A is the IGMP querier because the multicast server sends the
multicast stream directly to Switch A.
Figure 7
If all switch in between server and client are using the defult IGMP querier port
mode "auto", then we can disregard Switch C and Switch E. The IGMP
Join/Leave of the multicast client with issue will travel across
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