User guide

IGMP snooping IGMP snooping Functional Overview (Includes
iMG/RG Software Reference Manual (IGMP)
3-10
FIGURE 3-3 Two Hosts Join Two Different Multicast Channels
In case a multicast host is disconnected from the network, the IGMP process is able to detect such condition
checking the absence of IGMP reports on the port where the host left.
This process takes a time that is usually longer than the case where the host leaves the network in a gracefully
way. The IGMP process has to wait for no answers to the internal Generic Queries a number of times equals to
the Robustness attribute value.
The picture here below shows an example where an host disconnects from the network without sending any
IGMP leave message.