The value of tmnxMcacPolicyDefaultAction specifies the
action to be applied to multicast streams when they do
not match any of the multicast addresses defined in the
multicast CAC bundles for this policy.
The default action will be ignored if there is no policy
applied for the interface on which the multicast stream
is requested. In this case the protocol will handle the
request independent of the multicast CAC policy decision.
The default value of 'discard' for a policy means that
any multicast channels not configured (no entry in
tmnxMcacBdlChlEntry for this policy) on any bundle in
this policy will be dropped. The value of 'accept' means
that the channel not part of this policy can be accepted.