Cisco Catalyst 2975 Software Configuration Manual page 776

Configuring Standard QoS
Command
Step 5
trust [cos | dscp | ip-precedence]
Step 6 set {dscp new-dscp | ip precedence
new-precedence}
Step 7
police rate-bps burst-byte [exceed-action
{drop | policed-dscp-transmit}]
Catalyst 2975 Switch Software Configuration Guide
33-52
Purpose
Configure the trust state, which QoS uses to generate a CoS-based or
DSCP-based QoS label.
Note This command is mutually exclusive with the set command
within the same policy map. If you enter the trust command,
go to Step 6.
By default, the port is not trusted. If no keyword is specified when the
command is entered, the default is dscp.
The keywords have these meanings:
cos—QoS derives the DSCP value by using the received or default
•
port CoS value and the CoS-to-DSCP map.
dscp—QoS derives the DSCP value by using the DSCP value from
•
the ingress packet. For non-IP packets that are tagged, QoS derives
the DSCP value by using the received CoS value; for non-IP
packets that are untagged, QoS derives the DSCP value by using
the default port CoS value. In either case, the DSCP value is
derived from the CoS-to-DSCP map.
ip-precedence—QoS derives the DSCP value by using the IP
•
precedence value from the ingress packet and the
IP-precedence-to-DSCP map. For non-IP packets that are tagged,
QoS derives the DSCP value by using the received CoS value; for
non-IP packets that are untagged, QoS derives the DSCP value by
using the default port CoS value. In either case, the DSCP value is
derived from the CoS-to-DSCP map.
For more information, see the
section on page 33-57.
Classify IP traffic by setting a new value in the packet.
• For dscp new-dscp, enter a new DSCP value to be assigned to the
classified traffic. The range is 0 to 63.
For ip precedence new-precedence, enter a new IP-precedence
•
value to be assigned to the classified traffic. The range is 0 to 7.
Define a policer for the classified traffic.
By default, no policer is defined. For information on the number of
policers supported, see the
section on page 33-36.
For rate-bps, specify average traffic rate in bits per second (b/s).
•
The range is 8000 to 10000000000
For burst-byte, specify the normal burst size in bytes. The range is 8000
to 1000000.
(Optional) Specify the action to take when the rates are exceeded.
•
Use the exceed-action drop keywords to drop the packet. Use the
exceed-action policed-dscp-transmit keywords to mark down the
DSCP value (by using the policed-DSCP map) and to send the
packet. For more information, see the
Policed-DSCP Map" section on page
Chapter 33
"Configuring the CoS-to-DSCP Map"
"Standard QoS Configuration Guidelines"
"Configuring the
33-59.
Configuring QoS
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