The value of sapIgmpSnpgCfgMcacPrRsvMndBW specifies the bandwidth
pre-reserved for all the mandatory channels on a given interface
in kilo-bits per second(kbps).
If the value of sapIgmpSnpgCfgMcacUnconstBW is '0', no mandatory
channels are allowed. If the value of sapIgmpSnpgCfgMcacPrRsvMndBW
is '-1', then all mandatory and optional channels are allowed.
If the value of sapIgmpSnpgCfgMcacPrRsvMndBW is equal to the
value of sapIgmpSnpgCfgMcacUnconstBW, then all the unconstrained
bandwidth on a given interface is allocated to mandatory channels
configured through multicast CAC policy on that interface and no
optional groups (channels) are allowed.
The value of sapIgmpSnpgCfgMcacPrRsvMndBW should always be less
than or equal to that of sapIgmpSnpgCfgMcacUnconstBW. An attempt
to set the value of sapIgmpSnpgCfgMcacPrRsvMndBW greater than
that of sapIgmpSnpgCfgMcacUnconstBW will result in inconsistent
value error.