Cisco WS-C6506 - Page 1239

52-7
Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
OL-8978-04
Chapter 52 Configuring QoS
Understanding How QoS Works
Figure 52-5 PFC and PFC2 Classification, Marking, and Policing
Ye s
No
No
No
Ye s
From ingress
port or VLAN
IP
Packet?
ACL(s)
on ingress
interface?
1
Trust
received
DSCP?
1
Trust
received IP
precedence?
No
No
Ye s
Ye s
4
Set DSCP
to marked
down value
Use default
ingress ACL
To egress
interface
Ye s
No
No
Match
ACE in ACL?
Ye s
Ye s
Ye s
Ye s
77830
L3 Switching Engine (PFC/PFC2) classification, marking, and policing
Use received
DSCP
2
Set DSCP
from received
IP precedence
3
Set DSCP
from received
or port CoS
Use DSCP
from ACE
1
Traffic is from
an untrusted
port
1
Trust
received or
port CoS?
2
Specified by ACE keyword or by
port keyword and dscp ACE keyword
3
From IP precedence-to-DSCP map
4
From CoS-to-DSCP map
5
F
From DSCP-to-CoS map
1
rom DSCP markdown map
5
Derive CoS
from DSCP
Policing
rule in
ACE?
Markdown?
Out of
profile?
Drop
packet