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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 48 Configuring IP Multicast Routing
Configuring IP Multicast Routing
Configuring SSM Mapping
• Configuring Static SSM Mapping, page 48-20 (required)
• Configuring DNS-Based SSM Mapping, page 48-20 (required)
• Configuring Static Traffic Forwarding with SSM Mapping, page 48-21 (optional)

Configuring Static SSM Mapping

Beginning in privileged EXEC mode, follow these steps to configure static SSM mapping:
Go to this URL to see SSM mapping configuration examples:
http://www.cisco.com/en/US/products/sw/iosswrel/ps5207/products_feature_guide09186a00801a6d6f.
html

Configuring DNS-Based SSM Mapping

To configure DNS-based SSM mapping, you need to create a DNS server zone or add records to an
existing zone. If the routers that are using DNS-based SSM mapping are also using DNS for other
purposes, you should use a normally configured DNS server. If DNS-based SSM mapping is the only
DNS implementation being used on the router, you can configure a false DNS setup with an empty root
zone or a root zone that points back to itself.
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 ip igmp ssm-map enable Enable SSM mapping for groups in the configured SSM range.
Note By default, this command enables DNS-based SSM mapping.
Step 3 no ip igmp ssm-map query dns (Optional) Disable DNS-based SSM mapping.
Note Disable DNS-based SSM mapping if you only want to rely on
static SSM mapping. By default, the ip igmp ssm-map global
configuration command enables DNS-based SSM mapping.
Step 4 ip igmp ssm-map static access-list
source-address Configure static SSM mapping.
The ACL supplied for access-list defines the groups to be mapped to the
source IP address entered for the source-address.
Note You can configure additional static SSM mappings. If additional
SSM mappings are configured and the router receives an
IGMPv1 or IGMPv2 membership report for a group in the SSM
range, the switch determines the source addresses associated
with the group by using each configured ip igmp ssm-map
static command. The switch associates up to 20 sources per
group.
Step 5 Repeat Step 4 to configure additional
static SSM mappings, if required.
—
Step 6 end Return to privileged EXEC mode.
Step 7 show running-config Verify your entries.
Step 8 copy running-config startup-config (Optional) Save your entries in the configuration file.