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Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
OL-8978-04
Chapter 52 Configuring QoS
Configuring QoS on the Switch
Configuring the Trust State of a Port
This command configures the trust state of a port (for more information, see the
“Ethernet Ingress Port
Marking, Scheduling, Congestion Avoidance, and Classification” section on page 52-12
). By default, all
ports are untrusted.
To configure the trust state of a port, perform this task in privileged mode:
Note the following syntax guidelines when configuring the trust state of a port:
•
The
trust-ipprec
and
trust-dscp
keywords are supported only with a Layer 3 switching engine.
•
1q4t
ports (except Gigabit Ethernet) do not support the
trust-ipprec
and
trust-dscp
port keywords.
You must configure a
trust-ipprec
or
trust-dscp
ACL that matches the ingress traffic to apply the
trust-ipprec
or
trust-dscp
trust state.
•
On the
1q4t
ports (except Gigabit Ethernet), the
trust-cos
port keyword displays an error message,
activates the receive-queue drop thresholds, and—as indicated by the error message—does not apply
the
trust-cos
trust state to the traffic. You must configure a
trust-cos
ACL that matches the ingress
traffic to apply the
trust-cos
trust state.
This example shows how to configure port 1/1 with the
trust-cos
keyword:
Console> (enable)
set port qos 1/1 trust trust-cos
Port 1/1 qos set to trust-cos
Console> (enable)
Note
Only the ISL or 802.1Q frames carry the CoS values. Configure the ports with the
trust-cos
keyword
only when the received traffic is ISL or 802.1Q frames carrying the CoS values that you know to be
consistent with the network policy.
Configuring the CoS Value for a Port
Note
Whether or not QoS uses the CoS value that is applied with the
set port qos ...cos
command depends on
the trust state of the port and the trust state of the traffic that is received through the port. The
set port qos ... cos
command does not configure the trust state of the port or the trust state of the traffic that
is received through the port. To use the CoS value that is applied with the
set port qos ... cos
command,
configure a trust-CoS ACL that matches the ingress traffic; or for a port that receives no tagged traffic,
configure the port to trust CoS.
The unmarked frames from the ports that are configured as trusted and all frames from the ports that are
configured as untrusted are assigned the CoS value that is specified with this command.
Task
Command
Step 1
Configure the trust state of a port.
set port qos trust
{
untrusted
|
trust-cos
|
trust-ipprec
|
trust-dscp
}
Step 2
Verify the configuration.
show port qos