Cisco WS-C6506 - Page 1238

52-6
Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
OL-8978-04
Chapter 52 Configuring QoS
Understanding How QoS Works
Figure 52-4 PFC3 Classification, Marking, and Policing
Ye s
Ye s
7
Set internal
DSCP
to mutated
value
Egress
DSCP
mutation?
Ye s
No
No
No
Ye s
From ingress
LAN port or VLAN
From ingress
WAN port
IP
Packet?
ACL(s)
on ingress
interface?
1
Trust
received
DSCP?
1
Trust
received IP
precedence?
No
No
Ye s
Ye s
5
Set internal
DSCP
to marked
down value
Use default
ingress ACL
Ye s
No
No
Match
ACE in ACL?
Ye s
Ye s
Ye s
Ye s
77890
PFC3 classification, marking, and policing
Use received
DSCP
2
Set internal
DSCP
from received
IP precedence
3
Set internal
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
5
From CoS-to-DSCP map
4
For traffic forwarded by PFC3, only the ingress or egress
policing rule is applied, whichever is more severe.
7
F
6
Specified by ACE keyword
From DSCP-to-CoS map
8
From egress DSCP mutation map
1
rom DSCP markdown map
4
Policing
rule in
ACE?
Markdown?
Out of
profile?
Drop
packet
Ye s
No
No
No
No
ACL(s)
on egress
interface?
6
Trust
internal
DSCP?
No
5
Set internal
DSCP
to marked
down value
Use default
egress ACL
To egress
interface
No
No
Match
ACE in ACL?
Ye s
Ye s
Ye s
Ye s
Use DSCP
from ACE
Use internal
DSCP
Traffic is
untrusted
8
Derive CoS
from internal
DSCP
4
Policing
rule in
ACE?
Markdown?
Out of
profile?
Drop
packet