FortiOS 6 – Configuring QoS with managed FortiSwitch units

Configuring QoS with managed FortiSwitch units

Quality of Service (QoS) provides the ability to set particular priorities for different applications, users, or data flows.

NOTE: FortiGate does not support QoS for hard or soft switch ports.

FortiSwitch supports the following QoS configuration capabilities:

  • Mapping the IEEE 802.1p and Layer 3 QoS values (Differentiated Services and IP Precedence) to an outbound QoS queue number.
  • Providing eight egress queues on each port. l Policing the maximum data rate of egress traffic on the interface.

To configure the QoS for managed FortiSwitch units:

  1. Configure a Dot1p map.

A Dot1p map defines a mapping between IEEE 802.1p class of service (CoS) values (from incoming packets on a trusted interface) and the egress queue values. Values that are not explicitly included in the map will follow the default mapping, which maps each priority (0-7) to queue 0. If an incoming packet contains no CoS value, the switch assigns a CoS value of zero.

NOTE: Do not enable trust for both Dot1p and DSCP at the same time on the same interface. If you do want to trust both Dot1p and IP-DSCP, the FortiSwitch uses the latter value (DSCP) to determine the queue. The switch will use the Dot1p value and mapping only if the packet contains no DSCP value.

config switch-controller qos dot1p-map edit <Dot1p map name> set description <text> set priority-0 <queue number> set priority-1 <queue number> set priority-2 <queue number>

FortiGate CLI support for FortiSwitch features (on non-FortiLink ports)

set priority-3 <queue number> set priority-4 <queue number> set priority-5 <queue number> set priority-6 <queue number> set priority-7 <queue number>



  1. Configure a DSCP map.

A DSCP map defines a mapping between IP precedence or DSCP values and the egress queue values. For IP precedence, you have the following choices: o network-control—Network control o internetwork-control—Internetwork control o critic-ecp—Critic and emergency call processing (ECP) o flashoverride—Flash override o flash—Flash o immediate—Immediate

o priority—Priority o routine—Routine

config switch-controller qos ip-dscp-map edit <DSCP map name> set description <text> configure map <map_name> edit <entry name> set cos-queue <COS queue number>

set diffserv {CS0 | CS1 | AF11 | AF12 | AF13 | CS2 | AF21 | AF22 | AF23 | CS3 | AF31 | AF32 | AF33 | CS4 | AF41 | AF42 | AF43 | CS5 | EF |

CS6 | CS7} set ip-precedence {network-control | internetwork-control | critic-ecp

| flashoverride | flash | immediate | priority | routine} set value <DSCP raw value>




  1. Configure the egress QoS policy.

In a QoS policy, you set the scheduling mode for the policy and configure one or more CoS queues. Each egress port supports eight queues, and three scheduling modes are available:

  • With strict scheduling, the queues are served in descending order (of queue number), so higher number queues receive higher priority.
  • In simple round-robin mode, the scheduler visits each backlogged queue, servicing a single packet from each queue before moving on to the next one.
  • In weighted round-robin mode, each of the eight egress queues is assigned a weight value ranging from 0 to 63.

config switch-controller qos queue-policy edit <QoS egress policy name> set schedule {strict | round-robin | weighted} config cos-queue

Synchronizing the FortiGate unit with the managed FortiSwitch units

edit [queue-<number>] set description <text> set min-rate <rate in kbps> set max-rate <rate in kbps>

set drop-policy {taildrop | random-early-detection} set weight <weight value>





  1. Configure the overall policy that will be applied to the switch ports.

config switch-controller qos qos-policy edit <QoS egress policy name> set default-cos <default CoS value 0-7> set trust-dot1p-map <Dot1p map name> set trust-ip-dscp-map <DSCP map name> set queue-policy <queue policy name>



  1. Configure each switch port.

config switch-controller managed-switch edit <switch-id> config ports edit <port> set qos-policy <CoS policy>





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