Cisco 15327 - Manual (Page 233)

14-25
Ethernet Card Software Feature and Configuration Guide, R7.2
Chapter 14 Configuring Quality of Service
Multicast Priority Queuing QoS Restrictions
When bandwidth is allocated to multicast priority queuing but no output policy map is applied, the
default multicast congestion bandwidth is a minimum of 10 percent of the bandwidth not allocated to
multicast priority queuing.
When an output policy-map is applied to an interface, default multicast and default unicast share the
minimum bandwidth assigned to the default class. This default class is also known as the match-any
class. The minimum bandwidth of default multicast is 10 percent of the total default class bandwidth.
Multicast Priority Queuing QoS Restrictions
The following restrictions apply to multicast priority queuing QoS:
• The bandwidth allocation and utilization configured for multicast priority queuing traffic is global
and applies to all the ports on the ML-Series card, both POS and Fast Ethernet or Gigabit Ethernet,
regardless of whether these ports carry multicast priority queuing traffic. The rate of traffic can be
reduced for all ports on the ML-Series card when this feature is configured. Default multicast traffic
uses bandwidth only on the ports where it egresses, not globally like multicast priority queuing.
• Multicast priority queuing QoS is supported only for Layer 2 bridging.
• The ML-Series card supports a maximum of two multicast priority queuing classes.
• Unlike the rest of the ML-Series card QoS, multicast priority queuing QoS is not part of the
Cisco IOS MQC.
• Priority-mcast bandwidth allocation is per port and the maximum bandwidth configurable on an
ML1000-2 with cos priority-mcast is 1000 Mbps. But the load-balancing of multicast priority
queuing increases the effective bandwidth. For example, with an ML1000-2 with Gigabit
EtherChannel (GEC) and STS-24c circuits, the user can allocate 1000 Mbps per port, but will be
able to get 2000 Mbps total effective bandwidth due to the load-balancing.
Configuring Multicast Priority Queuing QoS
To configure a priority class for multicast traffic, use the global configuration cos priority-mcast
command, defined in Table 14-5 .