3Com 7757 Configuration Manual page 429

Table 335 IGMP Snooping messages
Message Sender Receiver Purpose
IGMP Multicas Multicast
general t router member
query and switch
message multicas and host
t switch
IGMP Multicas Multicast
group-sp t router member
ecific and switch
query multicas and host
message t switch
IGMP Host Multicast
host router
report and
message multicast
switch
Action of the multicast member switch
Query if Check if the
the message
multicast comes from
groups the original
contain router port
any
member
Query if a Send an IGMP group-specific query message to
specific the IP multicast group being queried.
IGMP
multicast
group
contains
any
member
Apply for Chec If yes, check if
joining a k if the port exists in
multicast the IP the MAC
group, or multi multicast group
respond cast
to an group
IGMP has a
query corres
message pondi
ng
MAC
multi
cast
group
If not:
Create a MAC multicast group and
■
notify the multicast router that a
member is ready to join the multicast
group.
Add the port to the MAC multicast
■
group and start the aging timer of the
port.
Add all router ports in the VLAN
■
owning this port to the MAC multicast
group.
Create an IP multicast group and add
■
the port to it.
Overview
If yes, reset the aging timer of
the router port
If not, notify the multicast router
that a member is in a multicast
group and start the aging timer
for the router port
If yes, add the IP
multicast group address
to the MAC multicast
group table.
If not, add the If yes,
port to the add
MAC multicast the
group, reset port to
the aging the IP
timer of the multica
port and check st
if the group.
corresponding
If not,
IP multicast
create
group exists.
an IP
multica
st
group
and
add
the
port to
it.
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