The value of vRtrPimNgIfMcacUnconstrainedBW specifies the bandwidth
assigned for interface's multicast cac policy traffic in kilo-bits
per second(kbps).
If the default value of '-1' is set, there is no constraint on
bandwidth allocated at the interface.
If the value of vRtrPimNgIfMcacUnconstrainedBW is set to '0' and if
a multicast cac policy is assigned on the interface, then
no group (channel) from that policy is allowed on that interface.