Enable SSM Globally

Enable Source Specific Multicast (SSM) to optimize PIM-SM by simplifying the many-to-many model (servers-to-receivers). Because most multicast applications distribute content to a group in one direction, SSM uses a one-to-many model that uses only a subset of the PIM-SM features. This model is more efficient and reduces the load on multicast routing devices.

Before you begin

  • Configure a unicast protocol, such as Routing Information Protocol (RIP) or Open Shortest Path First (OSPF), globally and on the interfaces where you want to configure PIM. For more information about RIP, see RIP configuration using EDM. For more information about OSPF, see OSPF configuration using EDM.

  • Enable PIM globally.

    Important

    Important

    After you enable PIM in SSM mode, the IGMP parameters take effect. To take full advantage of SSM, enable IGMPv3 if hosts that attach to the switch run IGMPv3 or configure the SSM table.

About this task

SSM is a global configuration. After you enable SSM on a switch, it is enabled on all interfaces that run PIM. On an SSM-enabled switch, SSM behavior is limited to the SSM group range. For non-SSM groups, the protocol behavior is PIM-SM.

Procedure

  1. In the navigation pane, expand Configuration > IP.
  2. Select PIM.
  3. Select the Globals tab.
  4. Select ssm (source specific multicast).
  5. Select the Enable check box.
  6. Select Apply.

    The system displays the following message:

    Are you sure you want to change the PIM mode? The traffic will not be stopped immediately. All Static Source Group entries in the SSM range will be deleted. Do you wish to continue?

  7. Select Yes.