Qos For Multicast Traffic; Policy For Fibre Channel Interfaces - Cisco Nexus 5000 Series Configuration Manual

Configuring QoS
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 six multicast queues applies to Nexus 5010 and Nexus 5020. For Nexus 5548 there are 128 multicast
queues. Additionally we need to highlight these are the queues at ingress.
For the Cisco Nexus 5548 switch, Cisco NX-OS Release 5.0(2)N1(1) provides 128 multicast queues at ingress.
For the Cisco Nexus 5020 switch and the Cisco Nexus 5020 switch, 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
• class-ip-multicast
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.
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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.
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.
Cisco Nexus 5000 Series NX-OS Quality of Service Configuration Guide
QoS for Multicast Traffic
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