3Com Switch 8800 Configuration Guide Chapter 29 PIM-SM Configuration29-4It should be noted that at least one router in an entire PIM-SM domain should beconfigured with Candidate-RPs and Candidate-BSRs.29.2.1 Enabling MulticastRefer to Chapter 26 Common Multicast Configuration.29.2.2 Enabling PIM-SMThis configuration can be effective only after multicast is enabled.Perform the following configuration in VLAN interface view.Table 29-1 Enabling PIM-SMOperation CommandEnable PIM-SM on an interface pim smDisable PIM-SM on an interface undo pim smRepeat this configuration to enable PIM-SM on other interfaces. Only one multicastrouting protocol can be enabled on an interface at a time.Once enabled PIM-SM on an interface, PIM-DM cannot be enabled on the sameinterface and vice versa.29.2.3 Entering the PIM ViewRefer to 28.2.4 Entering the PIM View.29.2.4 Configuring the Time Intervals for Ports to Send Hello PacketsIn general, PIM-SM broadcasts Hello packets on the PIM-SM-enabled port periodicallyto detect PIM neighbors and determine the designated router (DR).For details, refer to 28.2.3 Configuring the Time Intervals for Ports to Send HelloPackets.29.2.5 Configuring Candidate-BSRsIn a PIM domain, one or more candidate BSRs should be configured. A BSR (BootstrapRouter) is elected among candidate BSRs. The BSR takes charge of collecting andadvertising RP information.The automatic election among candidate BSRs is described as follows:One interface which has started PIM-SM must be specified when configuring the routeras the candidate BSR.
