QoS Ports and Queues Configuring QoS
page 30-28 OmniSwitch 6800/6850/9000 Network Configuration Guide March 2008
Note that on the OmniSwitch 6800 Series switch, the 802.1p bit for tagged packets received on untrusted
ports is set with the default 802.1p value. If the packet is untagged, however, then the DSCP bit is set with
the default DSCP value.
Fixed ports that are configured for 802.1Q are always trusted, regardless of QoS settings. They cannot be
configured as untrusted. For more information about configuring 802.1Q for fixed ports, see Chapter 15,
“Configuring 802.1Q.”
Mobile ports are also always trusted; however, mobile ports may or may not accept Q-tagged traffic.
Note about mobile ports. Mobile ports cannot be Q-tagged like fixed ports; however, a mobile port will
join a tagged VLAN if tagged traffic for that VLAN comes in on the mobile port and the vlan mobile-tag
command is enabled for that VLAN. For more information about enabling this command, see Chapter 4,
“Configuring VLANs.”
Ports must be both trusted and configured for 802.1Q traffic in order to accept 802.1p traffic.
The following applies to ports that are trusted (for 802.1p traffic, the ports must also be able to accept
802.1Q packets):
• The 802.1p or ToS/DSCP value is preserved.
• If the incoming 802.1p or ToS/DSCP flow does not match a policy, the switch places the flow into a
default queue and prioritizes the flow based on the 802.1p or ToS/DSCP value in the flow.
• If the incoming 802.1p or ToS/DSCP flow matches a policy, the switch queues the flow based on the
policy action.
The switch may be set globally so that all ports are trusted. Individual ports may be configured to override
the global setting.
Configuring Trusted Ports
By default, all ports (except 802.1Q-tagged ports and mobile ports) are untrusted. The trust setting may be
configured globally on the switch, or on a per-port basis.
To configure the global setting on the switch, use the qos trust ports command. For example:
-> qos trust ports
To configure individual ports as trusted, use the qos port trusted command with the desired slot/port
number. For example:
-> qos port 3/2 trusted
The global setting is active immediately; however, the port setting requires qos apply to activate the
change. For more information about the qos apply command, see “Applying the Configuration” on
page 30-54.
Using Trusted Ports With Policies
Whether or not the port is trusted is important if you want to classify traffic with 802.1p bits. If the policy
condition specifies 802.1p, the switch must be able to recognize 802.1p bits. (Note that the trusted port
must also be 802.1Q-tagged as described in “Configuring the Egress Queue Minimum/Maximum Band-
width” on page 30-27.) The 802.1p bits may be set or mapped to a single value using the policy action
802.1p command. In this example, the qos port command specifies that port 2 on slot 3 will be able to
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