Cisco Catalyst 2928, Software Configuration Manual

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31-7
Catalyst 2928 Switch Software Configuration Guide
OL-23389-01
Chapter 31 Configuring QoS
Configuring Standard QoS
Default Standard QoS Configuration
QoS is disabled. There is no concept of trusted or untrusted ports because the packets are not modified
(the CoS and IP precedence values in the packet are not changed). Traffic is switched in pass-through
mode (packets are switched without any rewrites and classified as best effort without any policing).
When QoS is enabled with the mls qos global configuration command and all other QoS settings are at
their defaults, traffic is classified as best effort (the CoS value is set to 0) without any policing. The
default port trust state on all ports is untrusted. The default ingress and egress queue settings are
described in the
“Default Ingress Queue Configuration” section on page 31-7 and the “Default Egress
Queue Configuration” section on page 31-7 .
Default Ingress Queue Configuration
Table 31-2 shows the default ingress queue configuration when QoS is enabled.
Table 31-3 shows the default CoS input queue threshold map when QoS is enabled.
Default Egress Queue Configuration
Table 31-4 shows the default egress queue configuration for each queue-set when QoS is enabled. All
ports are mapped to queue-set 1. The port bandwidth limit is set to 100 percent and rate unlimited.
Table 31-2 Default Ingress Queue Configuration
Feature Queue 1 Queue 2
Buffer allocation 90 percent 10 percent
Bandwidth allocation
1
1. The bandwidth is equally shared between the queues. SRR sends packets in shared mode only.
4 4
Priority queue bandwidth
2
2. Queue 2 is the priority queue. SRR services the priority queue for its configured share before servicing the other queue.
0 10
WTD drop threshold 1 100 percent 100 percent
WTD drop threshold 2 100 percent 100 percent
Table 31-3 Default CoS Input Queue Threshold Map
CoS Value Queue ID–Threshold ID
0–4 1 – 1
5 2
–
1
6, 7 1 – 1
Table 31-4 Default Egress Queue Configuration
Feature Queue 1 Queue 2 Queue 3 Queue 4
Buffer allocation 25 percent 25 percent 25 percent 25 percent
WTD drop threshold 1 100 percent 200 percent 100 percent 100 percent
WTD drop threshold 2 100 percent 200 percent 100 percent 100 percent