Cisco Cisco IOS Software Release 12.2(33)SRE
1
Extended ACL Support for IGMP to Support SSM
in IPv4
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.
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.
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:
Command Reference Information
Command reference information is included in the
Cisco IOS IP Multicast Command Reference
,
Release 12.2SR, at the following URL:
New or Modified Commands
The following command is modified for this feature:
•
ip igmp access-group
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.
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.