Extended ACL Support for IGMP to Support SSM in IPv4
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Extended ACL Support for IGMP to Support SSM in IPv4
Extended ACL Support for IGMP to Support SSM in IPv4
IGMP Version 3 accommodates extended access lists, which allow you to leverage an important advantage of Source Specific Multicast (SSM) in IPv4, that of basing access on source IP address. Prior to this feature, an IGMP access list accepted only a standard access list, allowing membership reports to be filtered based only on multicast group addresses.
IGMPv3 allows multicast receivers not only to join to groups, but to groups including or excluding sources. For appropriate access control, it is therefore necessary to allow filtering of IGMPv3 messages not only by group addresses reported, but by group and source addresses. IGMP extended access lists introduce this functionality. Using SSM with an IGMP extended access list (ACL) allows you to permit or deny source S and group G (S, G) in IGMPv3 reports, thereby filtering IGMPv3 reports based on source address, group address, or both.
Configuration Information
Configuration information is included in the "Customizing IGMP" chapter in the Cisco IOS IP Multicast Configuration Guide, Release 12.4T, at the following URL:
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http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124tcg/timc_c/mcbigmpt.htm
Command Reference Information
Command reference information is included in the Cisco IOS IP Multicast Command Reference, Release 12.2SR, at the following URL:
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New or Modified Commands
The following command is modified for this feature:
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Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.
© 2006 Cisco Systems, Inc. All rights reserved.
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