Method and apparatus for providing quality of service across a switched backplane for multicast packets

A method and system is provided to enable quality of service across a backplane switch for multicast packets. For multicast traffic, an egress queue manager manages congestion control in accordance with multicast scheduling flags. A multicast scheduling flag is associated with each egress queue capable of receiving a packet from a multicast ingress queue. When the multicast scheduling flag is set and the congested egress queue is an outer queue, the egress queue manager refrains from dequeueing any marked multicast packets to the destination ports associated with the congested outer queue until the congestion subsides. When the congested egress queue is a backplane queue, the egress queue manager refrains from dequeuing any marked multicast packets to the destination ports on the destination blade associated with the congested backplane queue until the congestion subsides.