Configuration Guide User guide

FastIron Configuration Guide 1963
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Chapter
51
Quality of Service
Table 328 lists the individual Brocade FastIron switches and the Quality of Service (QoS) features
they support. These features are supported in the Layer 2, base Layer 3, edge Layer 3, and full
Layer 3 software images, except where explicitly noted.
QoS overview
Quality of Service (QoS) features are used to prioritize the use of bandwidth in a switch. When QoS
features are enabled, traffic is classified as it arrives at the switch, and processed through on the
basis of configured priorities. Traffic can be dropped, prioritized for guaranteed delivery, or subject
to limited delivery options as configured by a number of different mechanisms.
This chapter describes how QoS is implemented and configured in FastIron devices.
Classification is the process of selecting packets on which to perform QoS, reading the QoS
information, and assigning a priority to the packets. The classification process assigns a priority to
packets as they enter the switch. These priorities can be determined on the basis of information
contained within the packet or assigned to the packet as it arrives at the switch. Once a packet or
traffic flow is classified, it is mapped to a forwarding priority queue.
Packets on Brocade devices are classified in up to eight traffic classes with values from 0 to 7.
Packets with higher priority classifications are given a precedence for forwarding.
TABLE 328 Supported QoS features
Feature FESX
FSX 800
FSX 1600
FWS FCX ICX 6610 ICX 6430
ICX 6450
802.1p Quality of Service (QoS):
• Strict Priority (SP)
• Weighted Round Robin (WRR)
• Combined SP and WRR
• 8 priority queues
Yes Yes Yes Yes Yes
802.1p priority override Yes Yes Yes Yes Yes
802.1p marking Yes Yes Yes Yes Yes
DiffServ support Yes Yes Yes Yes Yes
DSCP-based QoS Yes Yes Yes Yes Yes
QoS mappings Yes Yes Yes Yes Yes
User-configurable scheduler profiles No No Yes Yes Yes