Chapter 5
Setup and Configuration
RUGGEDCOM ROS
User Guide
202
Managing Multicast Filtering
Section 5.9
Managing Multicast Filtering
Multicast traffic can be filtered using either static multicast groups, IGMP (Internet Group Management Protocol)
snooping, or GMRP (GARP Multicast Registration Protocol).
The following sections describe how to configure and manage multicast filtering:
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Section 5.9.1, “Multicast Filtering Concepts”
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Section 5.9.1.2, “GMRP (GARP Multicast Registration Protocol)”
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Section 5.9.2, “Viewing a List of IP Multicast Groups”
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Section 5.9.3, “Viewing a Summary of Multicast Groups”
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Section 5.9.4, “Configuring IGMP”
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Section 5.9.5, “Configuring GMRP Globally”
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Section 5.9.6, “Configuring GMRP for Specific Ethernet Ports”
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Section 5.9.7, “Managing Static Multicast Groups”
Section 5.9.1
Multicast Filtering Concepts
The following sections describe some of the concepts important to the implementation of multicast filtering in
ROS:
•
•
Section 5.9.1.2, “GMRP (GARP Multicast Registration Protocol)”
Section 5.9.1.1
IGMP
IGMP is used by IP hosts to report their host group memberships with multicast routers. As hosts join and leave
specific multicast groups, streams of traffic are directed to or withheld from that host.
The IGMP protocol operates between multicast routers and IP hosts. When an unmanaged switch is placed
between multicast routers and their hosts, the multicast streams will be distributed to all ports.This may introduce
significant traffic onto ports that do not require it and receive no benefit from it.
IGMP Snooping, when enabled, will act on IGMP messages sent from the router and the host, restricting traffic
streams to the appropriate LAN segments.
Example: IGMP In Operation
The following network diagram provides a simple example of the use of IGMP.