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Configuration prerequisites

Before you can configure PIM-SM, you must prepare the router as follows:

  1. Configure an IP interface.
  2. Disable DVMRP from the interface on which you want to configure PIM-SM because you cannot configure PIM-SM and DVMRP on the same interface.

    Note Note: Changing the configuration from PIM to DVMRP, or from DVMRP to PIM, is not recommended while multicast traffic is flowing on the network.

    1. A switch can have a mix of DVMRP and PIM-SM interfaces if it is configured as an multicast border router (MBR).
    2. An interface can only be configured with one multicast routing protocol at a time (PIM-SM or DVMRP).
  3. Configure a unicast protocol (RIP or OSPF) globally and on the interfaces where you want to configure PIM-SM.
    4. PIM-SM requires a unicast protocol to use in order to multicast traffic within the network when performing the Reverse Path Forwarding (RFP) check. PIM-SM uses the information from the unicast routing table to create and maintain the shared and shortest multicast tree that enables PIM-enabled routers to communicate. The unicast routing table must contain a route to every multicast source in the network as well as routes to PIM entities like the RPs and BSR.
  4. To configure PIM-SM on an 8000 Series switch, the following configurations are required:
    5. ­ Enable PIM-SM globally.
    ­ Enable PIM-SM on individual interfaces.
    ­ Configure one or several RPs for the groups that will be used by a multicast application in the network.
    ­ Configure one or several BSRs to propagate RP information to all switches in the network.
    ­ If connecting a PIM-SM domain to a DVMRP domain, configure the switch interconnecting the domains as an MBR switch with the corresponding PIM-SM interfaces enabled with PIM-SM, and DVMRP interfaces enabled with DVMRP.

    Note Note: Routes to sources in a PIM domain should not have a lower cost through the DVMRP domain in order for multicast routing from these sources to work properly. MBR switches should be configured with this design guideline in mind.

See also:
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