Information About IGMP Static Group Range Support
IGMP Static Group Range Support Overview
Prior to the introduction of the IGMP Static Group Range Support feature, there was no option to specify group ranges for static group membership. Administering devices that required static group membership entries on many interfaces was challenging in some network environments because each static group had to be configured individually. The result was configurations that were excessively long and difficult to manage.
The IGMP Static Group Range Support feature introduces the capability to configure group ranges in class maps and attach class maps to the interface.
Class Maps for IGMP Static Group Range Support
A class is a way of identifying a set of packets based on its contents. A class is designated through class maps. Typically, class maps are used to create traffic policies. Traffic policies are configured using the modular quality of service (QoS) command-line interface (CLI) (MQC). The normal procedure for creating traffic policies entails defining a traffic class, creating a traffic policy, and attaching the policy to an interface.
The IGMP Static Group Range Support feature introduces a type of class map that is used to define group ranges, group addresses, Source Specific Multicast (SSM) channels, and SSM channel ranges. Once created, the class map can be attached to interfaces.
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Create an IGMP static group class map.
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Define the group entries associated with the class map.
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Attach the class map to an interface.
Unlike QoS class maps, which are defined by specifying numerous match criteria, IGMP static group class maps are defined by specifying multicast groups entries (group addresses, group ranges, SSM channels, and SSM channel ranges). Also, IGMP static group range class maps are not configured in traffic policies. Rather, the ip ignmp static-group command has been extended to support IGMP static group ranges.
Once a class map is attached to an interface, all group entries defined in the class map become statically connected members on the interface and are added to the IGMP cache and IP multicast route (mroute) table.
General Procedure for Configuring IGMP Group Range Support
To configure the IGMP Static Group Range Support feature, you would complete the following procedure:
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Create an IGMP static group class map (using the class-map type multicast-flows command).
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Define the group entries associated with the class map (using the group command).
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Attach the class map to an interface (using the ip igmp static-group command).
The class-map type multicast-flows command is used to enter multicast-flows class map configuration mode to create or modify an IGMP static group class map.
Unlike QoS class maps, which are defined by specifying numerous match criteria, IGMP static group class maps are defined by specifying multicast groups entries (group addresses, group ranges, SSM channels, and SSM channel ranges). The following forms of the group command are entered from multicast-flows class map configuration mode to define group entries to associate with the class map:
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group group-address
Defines a group address to be associated with an IGMP static group class map.
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group group-address to group-address
Defines a range of group addresses to be associated with an IGMP static group class map.
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group group-address source source-address
Defines an SSM channel to be associated with an IGMP static group class map.
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group group-address to group-address source source-address
Defines a range of SSM channels to be associated with an IGMP static group class map.
Unlike QoS class maps, IGMP static group range class maps are not configured in traffic policies. Rather, the ip igmp static-group command has been extended to support IGMP static group ranges. After creating an IGMP static group class map, you can attach the class map to interfaces using the ip igmp static-group command with the class-map keyword and class-map-name argument. Once a class map is attached to an interface, all group entries defined in the class map become statically connected members on the interface and are added to the IGMP cache and IP multicast route (mroute) table.
Additional Guidelines for Configuring IGMP Static Group Range Support
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Only one IGMP static group class map can be attached to an interface.
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If an IGMP static group class map is modified (that is, if group entries are added to or removed from the class map using the group command), the group entries that are added to or removed from the IGMP static group class map are added to or deleted from the IGMP cache and the mroute table, respectively.
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If an IGMP static group class map is replaced on an interface by another class map using the ip igmp static-group command, the group entries associated with old class map are removed, and the group entries defined in the new class map are added to the IGMP cache and mroute table.
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The ip igmp static-group command accepts an IGMP static group class map for the class-map-name argument, regardless of whether the class map configuration exists. If a class map attached to an interface does not exist, the class map remains inactive. Once the class map is configured, all group entries associated with the class map are added to the IGMP cache and mroute table.
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If a class map is removed from an interface using the no form of the ip igmp static-group command, all group entries defined in the class map are removed from the IGMP cache and mroute tables.
Benefits of IGMP Static Group Range Support
The IGMP Static Group Range Support feature provides the following benefits:
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Simplifies the administration of devices that require many interfaces to be configured with many different ip igmp static-group command configurations by introducing the capability to configure group ranges in class maps and attach class maps to the ip igmp static-group command.
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Reduces the number of commands required to administer devices that require many ip igmp static-group command configurations.