Cisco Catalyst 3120 User Manual

36-6
Cisco Catalyst Blade Switch 3120 for HP Software Configuration Guide
OL-12247-01
Chapter 36 Configuring QoS
Understanding QoS
After classification, the packet is sent to the policing, marking, and the ingress queueing and scheduling
stages.
Figure 36-3 Classification Flowchart
8
6834
Generate the DSCP based on
IP precedence in packet. Use
the IP-precedence-to-DSCP
map. Use the DSCP value to
generate the QoS label.
Assign default
port CoS.
Ye s
Ye s
No
No
No
Ye s N o
(Optional) Modify the
DSCP by using the
DSCP-to-DSCP-mutation
map. Use the DSCP
value to generate
the QoS label.
Read ingress interface
configuration for classification.
Assign DSCP identical
to DSCP in packet.
Check if packet came
with CoS label (tag).
Use the CoS value to
generate the QoS label.
Generate DSCP from
CoS-to-DSCP map.
Use the DSCP value to
generate the QoS label.
Ye s
Read next ACL. Is there
a match with a "permit" action?
Assign the DSCP or CoS as specified
by ACL action to generate the QoS label.
Assign the default
DSCP (0).
Are there any (more) QoS ACLs
configured for this interface?
Check if packet came
with CoS label (tag).
Use CoS
from frame.
Start
Trust CoS (IP and non-IP traffic).
IP and
non-IP
traffic
Trust DSCP or
IP precedence
(non-IP traffic).
Trust IP
precedence
(IP traffic).
Trust DSCP (IP traffic).
DoneDone
Done
Done
Assign the default po
rt
CoS and generate a
DSCP from the
CoS-to-DSCP map.
Generate the DSCP by using
the CoS-to-DSCP map.

Cisco Catalyst 3120 Specifications

General

Brand	Cisco
Model	Catalyst 3120
Category	Switch
Language	English