Flowcharts - Cisco WS-X6066-SLB-APC - Content Switching Module Software Manual

Chapter 41 Configuring QoS
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Flowcharts

Figure 41-1
more details of the traffic flow through QoS features.
Figure 41-1 Traffic Flow Through QoS Features
Ethernet
Frame enters
ingress
switch
port
ATM-LANE
Cell enters
ingress
switch
port
Traffic that is Layer 3 switched does not go through the Multilayer Switch Feature Card (MSFC or
Note
MSFC2) and retains the CoS value assigned by the Layer 3 switching engine.
Enter the show port capabilities command to see the queue structure of a port (for more information,
Note
see the
78-13315-02
Scheduling is the assignment of traffic to a queue. QoS assigns traffic based on CoS values.
Congestion avoidance is the process by which QoS reserves ingress and egress port capacity for
traffic with high-priority CoS values. QoS implements congestion avoidance with CoS value-based
drop thresholds. A drop threshold is the percentage of buffer utilization at which traffic with a
specified CoS value is dropped, leaving the buffer available for traffic with higher-priority CoS
values.
Policing is the process by which the switch limits the bandwidth consumed by a flow of traffic.
Policing can mark or drop traffic.
Except where specifically differentiated, Layer 3 switching engine refers to either:
Supervisor Engine 2 with Layer 3 Switching Engine II (Policy Feature Card 2 or PFC2)
–
Supervisor Engine 1 with Layer 3 Switching Engine WS-F6K-PFC (Policy Feature Card
–
or PFC)
shows how traffic flows through the QoS features;
L3 Switching Engine*
or
L2 Switching Engine
*PFC or PFC2
CoS = 0 for all traffic
(not configurable)
"Receive Queues" section on page 41-11
Ethernet
Transmit
egress
port
CoS = 0 for all traffic
(not configurable)
Multilayer Switch
Feature Card (MSFC)
ATM-LANE
Transmit
egress
port
and the "Transmit Queues" section on page
Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
Understanding How QoS Works
Figure 41-2 through Figure 41-7
frame
FlexWAN Module
interfaces
cell
show
41-25).
41-3