Reference Guide

682 | PIM Source-Specific Mode (PIM-SSM)
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Enable PIM-SSM
To enable PIM-SSM:
Display address ranges in the PIM-SSM range using the command
show ip pim ssm-range from EXEC
Privilege mode.
Figure 31-2. Enabling PIM-SSM
Use PIM-SSM with IGMP version 2 Hosts
PIM-SSM requires receivers that support IGMP version 3. You can employ PIM-SSM even when receivers
support only IGMP version 1 or version 2 by translating (*,G) entries to (S,G) entries.
Translate (*,G) entries to (S,G) entries using the command
ip igmp ssm-map acl source from
CONFIGURATION mode. In a standard access list, specify the groups or the group ranges that you want
to map to a source. Then, specify the multicast source.
• When a SSM map is in place and FTOS cannot find any matching access lists for a group, it continues
to create (*,G) entries because there is an implicit deny for unspecified groups in the ACL.
• When you remove the mapping configuration, FTOS removes the corresponding (S,G) states that it
created and reestablishes the original (*,G) states.
• You may enter multiple
ssm-map commands for different access lists. You may also enter multiple
ssm-map commands for the same access list, as long as they use different source addresses.
Step Task Command Syntax Command Mode
1 Create an ACL that uses permit rules to specify what range of
addresses should use SSM. You must at least include one
rule, permit 232.0.0.0/8, which is the default range for
PIM-SSM.
ip access-list
standard name
CONFIGURATION
2 Enter the command ip pim ssm-range and specify the ACL
you created.
ip pim ssm-range
acl-name
CONFIGURATION
R1(conf)#do show run pim
!
ip pim rp-address 10.11.12.2 group-address 224.0.0.0/4
ip pim ssm-range ssm
R1(conf)#do show run acl
!
ip access-list standard ssm
seq 5 permit host 239.0.0.2
R1(conf)#do show ip pim ssm-range
Group Address / MaskLen
239.0.0.2 / 32