The only VCs eligible for idling are those with a current 1-second activity rate less than or equal to the value configured by the ip pim minimum-vc-rate interface configuration command on the ATM interface. Activity level is measured in packets per second (pps).
The VC with the least amount of activity below the configured ip pim minimum-vc-rate pps rate is idled.
If the ip pim minimum-vc-rate command is not configured, all VCs are eligible for idling.
If other VCs are at the same activity level, the VC with the highest fanout (number of leaf routers on the multipoint VC) is idled.
The activity level is rounded to three orders of magnitude (less than 10 pps, 10 to 100 pps, and 100 to 1000 pps). Therefore, a VC that has 40 pps activity and another that has 60 pps activity are considered to have the same rate, and the fanout count determines which one is idled. If the first VC has a fanout of 5 and the second has a fanout of 3, the first one is idled.
Idling a VC means releasing the multipoint VC that is dedicated for the multicast group. The traffic of the group continues to be sent; it is moved to the static map VC. Packets will flow over a shared multipoint VC that delivers packets to all PIM neighbors.
If all VCs have a 1-minute rate greater than the pps value, the new group (that exceeded the ip pim vc-count number) will use the shared multipoint VC.
