Field
Description
All Multicast Groups
Select whether all multicast groups, i.e. the complete multicast
address range 224.0.0.0/4, are to be forwarded from the defined
Source Interface to the defined Destination Interface To do
this, check Enabled
Disable the option if you only want to forward one defined mul-
ticast group to a particular interface.
The option is not activated by default.
Multicast Group Address Only for All Multicast-Groups =
*
Enter here the address of the multicast group you want to for-
ward from a defined Source Interface to a defined Destination
Interface
Source Interface
Select the interface on your device to which the selected multic-
ast group is sent.
Destination Interface
Select the interface on your device to which the selected multic-
ast group is to be forwarded.
10.5.2 IGMP
IGMP (Internet Group Management Protocol, see RFC 3376) is used to signal the informa-
tion about group (membership) in a subnet. As a result, only the packets explicitly wanted
by a host enter the subnet.
Special mechanisms ensure that the requirements of the individual clients are taken into
consideration. At the moment there are three versions of IGMP (V1 - V3); most current sys-
tems use V3, and less often V2.
Two packet types play a central role in IGMP: queries and reports.
Queries are only transmitted from a router. If several IGMP routers exist in a network, the
router with the lowest IP address is the "querier". We differentiate here between a general
query (sent to 224.0.0.1), a group-specific query (sent to a group address) and the group-
and-source-specific query (sent to a specific group address). Reports are only sent by
hosts to respond to queries.
In this menu, you configure the interfaces on which IGMP is to be enabled.
10 Routing
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186
funkwerk TR200aw/bw