HP Cisco Nexus 5000 Cisco Nexus 5000 Series Switch CLI Software Configuration - Page 474

QoS for Multicast Traffic Information About QoS If you add a system class, a queue is assigned to the class. You must reconfigure the bandwidth allocation on all affected interfaces. Bandwidth is not dedicated automatically to user-defined system classes. You can configure a strict priority queue. This queue is serviced before all other queues except the control traffic queue (which carries control rather than data traffic). QoS for Multicast Traffic The system provides six multicast queues per interface and allocates one queue for each system class. By default, all multicast Ethernet traffic is classified into the default drop system class. This traffic is serviced by one multicast queue. Optimized multicasting allows use of the unused multicast queues to achieve better throughput for multicast frames. If optimized multicast is enabled for the default drop system class, the system will use all six queues to service the multicast traffic (all six queues are given equal priority). If you define a new system class, a dedicated multicast queue is assigned for this class. This queue is removed from the set of queues available for the optimized multicast class. Optimized multicasting achieves better throughput and improves performance for multicast frames. The system provides two predefined class maps for matching broadcast or multicast traffic. These class maps are convenient for creating separate policy maps for unicast and multicast traffic. The predefined class maps are as follows: • class-all-flood The class-all-flood class map matches all broadcast, multicast, and unknown unicast traffic (across all CoS values). If you configure a policy map with the class-all-flood class map, the system automatically uses all available multicast queues for this traffic. • class-ip-multicast The class-ip-multicast class map matches all IP multicast traffic. Policy options configured in this class map apply to traffic across all Ethernet CoS values. For example, if you enable optimized multicast for this class, the IP multicast traffic for all CoS values is optimized. Note If you configure either of these predefined class maps as a no-drop class, the priority flow control capability is applied across all Ethernet CoS values. In this configuration, pause will be applied to unicast and multicast traffic. Policy for Fibre Channel Interfaces The egress queues are not configurable for native Fibre Channel interfaces. Two queues are available as follows: • A strict priority queue to serve high-priority control traffic. • A queue to serve all data traffic and low-priority control traffic. Cisco Nexus 5000 Series Switch CLI Software Configuration Guide 428 OL-16597-01