Guidelines And Limitations - Cisco Nexus 7000 Series Configuration Manual

Guidelines and Limitations

• You must be familiar with "Using Modular QoS CLI."
• You are logged on to the switch.
• You are in the default VDC. A VDC is a logical representation of a set of system resources. You can use
Guidelines and Limitations
The network QoS policy has the following configuration guidelines and limitations:
Note These guidelines and limitations are applicable to all F-Series edge, M3, and FabricPath mode ports.
• You must configure and apply a network qos policy only to the default VDC.
• Selecting a template with a no-drop CoS value does not automatically give no-drop behavior to it. The
• When the port MTU is configured on an interface, it overrides the network qos MTU.
• In releases earlier than Cisco NX-OS Release 6.2(1), the Fabric Extender (FEX) interfaces do not support
• The FEX port channel requires a minimum MTU setting of 1058 for traffic with CoS 5–CoS 7. The FEX
• Changing the network qos policy is a disruptive operation and it can cause traffic drops on any or all
• DCB network qos policies pertain to F-Series modules. DCE network qos policies are created only when
PFC and F1 Series Module Ports
• When PFC is enabled on a port, precision time protocol (PTP) is not supported on the port.
• The pong utility is not supported on a VDC when PFC is enabled on any of the ports in the same VDC.
• PFC is not supported when PTP is enabled on the same port or when the pong utility is enabled in the
Configuring iSCSI
• As a best practice, both iSCSI and FCoE should be configured on the same CoS (vl) in the network-qos
Cisco Nexus 7000 Series NX-OS Quality of Service Configuration Guide
142
the switchto vdc command with a VDC number.
no-drop behavior is enabled for those CoS values only on ports where priority flow control (PFC) is
successfully negotiated or turned on.
the MTU changes made to a QoS policy template.
fails when the MTU is less than 1058 and does not register with the switch.
ports across VDCs.
DCE network enabled line cards are inserted into a chassis.
same VDC.
policy for the default-nq-7e-policy and default-nq-6e-policy templates.
• Avoid using CoS 4 for iSCSI in the default-nq-6e-policy template.
(CoS 4 is reserved for no-drop control traffic.)
• Avoid using CoS 4 for iSCSI in the default-nq-4e-policy template.
Configuring Network QoS