Cisco Systems 3750E manual 36-53

Chapter 36 Configuring QoS

Configuring Standard QoS

	Command	Purpose
Step 5
	trust [cos dscp ip-precedence]	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 “Configuring the CoS-to-DSCP Map”
		section on page 36-63.
Step 6 set {dscp new-dscpip precedence		Classify IP traffic by setting a new value in the packet.
	new-precedence}	• 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.
Step 7
	police rate-bpsburst-byte[exceed-action	Define a policer for the classified traffic.
	{drop policed-dscp-transmit}]	By default, no policer is defined. For information on the number of
		policers supported, see the “Standard QoS Configuration Guidelines”
		section on page 36-35.
		• For rate-bps,specify average traffic rate in bits per second (b/s).
		The range is 8000 to 1000000000.
		• 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 “Configuring the
		Policed-DSCP Map” section on page 36-65.

	Catalyst 3750-E and 3560-E Switch Software Configuration Guide
OL-9775-02		36-53