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Administration Guide

Determining the egress queue

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Determining the egress queue

To determine the egress queue value for the packet, the FortiSwitch unit uses the configured trust values (and mappings) on the port and the QoS/CoS fields in the packet.

Packets with DSCP and CoS values

If the port is set to trust DSCP, the switch uses this value to find the queue assignment in the DSCP map for the port.

If the port is set to trust Dot1p and not to trust DSCP, the switch uses the packet’s CoS value to look up the queue assignment in the Dot1p map for the port.

If the port is not set to trust Dot1p, the switch uses the default queue 0.

Packets with a CoS value but no DSCP value

The switch ignores the trust DSCP value.

  • If the port is set to trust Dot1p, the switch uses the packet’s CoS value to look up the queue assignment in the Dot1p map for the port.
  • If the port is not set to trust Dot1p, the switch uses the default queue 0.

Packets with a DSCP value but no CoS value

If the port is set to trust DSCP, the switch uses the packet’s DSCP value to look up the queue assignment in the DSCP map for the port.

If the port is set to trust Dot1p but not to trust DSCP, the switch uses the default CoS value of the port to look up the queue assignment in the Dot1p map for the port.

If the port is not set to trust Dot1p, the switch uses the default queue 0.

Determining the egress queue

To determine the egress queue value for the packet, the FortiSwitch unit uses the configured trust values (and mappings) on the port and the QoS/CoS fields in the packet.

Packets with DSCP and CoS values

If the port is set to trust DSCP, the switch uses this value to find the queue assignment in the DSCP map for the port.

If the port is set to trust Dot1p and not to trust DSCP, the switch uses the packet’s CoS value to look up the queue assignment in the Dot1p map for the port.

If the port is not set to trust Dot1p, the switch uses the default queue 0.

Packets with a CoS value but no DSCP value

The switch ignores the trust DSCP value.

  • If the port is set to trust Dot1p, the switch uses the packet’s CoS value to look up the queue assignment in the Dot1p map for the port.
  • If the port is not set to trust Dot1p, the switch uses the default queue 0.

Packets with a DSCP value but no CoS value

If the port is set to trust DSCP, the switch uses the packet’s DSCP value to look up the queue assignment in the DSCP map for the port.

If the port is set to trust Dot1p but not to trust DSCP, the switch uses the default CoS value of the port to look up the queue assignment in the Dot1p map for the port.

If the port is not set to trust Dot1p, the switch uses the default queue 0.