Configuring split ports

On FortiSwitch models that provide 40G/100G QSFP (quad small form-factor pluggable) interfaces, you can install a breakout cable to convert one 40G/100G interface into four 10G/25G interfaces.

This section covers the following topics:

• Notes
• Configuring a split port
• Configuring forward error correction

Notes

• Splitting ports is supported on the following FortiSwitch models:
  • FS-3032D—Ports 5 to 28 are splittable.
  • FS-3032E—Ports can be split into 4 x 25G when configured in 100G QSFP28 mode or can be split into 4 x 10G when configured in 40G QSFP mode. Use the set <port-name>-phy-mode disabled command to disable some 100G ports to allow up to sixty-two 100G/25G/10G ports.
  • FS-524D and FS-524D-FPOE—Ports 29 and 30 are splittable as 4 x 10G.
  • FS-548D and FS-548D-FPOE—Ports 53 and 54 are splittable as 4 x 10G.
  • FS-1048E—In the 4 x 100G configuration, ports 49, 50, 51, and 52 are splittable as 4 x 25G, 4 x 10G, 4 x 1G, or 2 x 50G. Only two of the available ports can be split.
  • FS-1048E—In the 4 x 4 x 25G configuration, ports 49, 50, 51, and 52 are splittable as 4 x 4 x 25G or 2 x 50G. All four ports can be split, but ports 47 and 48 are disabled.
  • FS-1048E—In the 6 x 40G configuration, ports 49, 50, 51, 52, 53, 54 are splittable as 4 x 10G or 4 x 1G.

  • FS-T1024E—Ports 25 and 26 have a maximum speed of 100G; each port can be split into four subports; each split port has a maximum speed of 25G.

  • FS-1024E—Ports 25 and 26 have a maximum speed of 100G; each port can be split into four subports; each split port has a maximum speed of 25G.

  Use the set port-configuration ? command to check which ports are supported for each model.

• Currently, the maximum number of ports supported in software is 64 (including the management port). Therefore, only 10 QSFP ports can be split. This limitation applies to all of the models, but only the 3032D, the 3032E, and the 1048E models have enough ports to encounter this limit.
• Starting in FortiOS 6.2.0, splitting ports is supported in FortiLink mode (that is, the FortiSwitch unit managed by a FortiGate unit).
• Use 10000full for the general 10G interface configuration. If that setting does not work, use 10000cr for copper connections (with copper cables such as 10GBASE-CR) or use 10000sr for fiber connections (fiber optic transceivers such as 10GBASE-SR/-LR/-ER/-ZR).

Configuring a split port

Use the following commands to configure a split port:

config switch phy-mode

set port-configuration {default | disable-port54 | disable-port41-48 | 4x100G | 6x40G | 4x4x25G}

set {<port-name>-phy-mode <single-port| 4x25G | 4x10G | 4x1G | 2x50G}

...

(one entry for each port that supports split port)

end

The following settings are available:

• disable-port54—For 548D and 548D-FPOE, only port53 is splittable; port54 is unavailable.
• disable-port41-48—For 548D and 548D-FPOE, port41 to port48 are unavailable, but you can configure port53 and port54 in split-mode.
• 4x100G—For 1048E, enable the maximum speed (100G) of ports 49 through 52. Ports 53 and 54 are disabled.
• 6x40G—For 1048E, enable the maximum speed (40G) of ports 49 through 54.
• 4x4x25G—For 1048E, enable the maximum speed (100G) of ports 49 through 52; each split port has a maximum speed of 25G. Ports 47 and 48 are disabled.
• single-port—Use the port at the full base speed without splitting it.
• 4x25G—For 100G QSFP only, split one port into four subports of 25 Gbps each.
• 4x10G—For 40G or 100G QSFP only, split one port into four subports of 10Gbps each.
• 4x1G—For 40G or 100G QSFP only, split one port into four subports of 1 Gbps each.
• 2x50G—For 100G QSFP only, split one port into two subports of 50 Gbps each.

In the following example, a FortiSwitch 3032D model is configured with ports 10, 14, and 28 set to 4x10G:

config switch phy-mode

set port5-phy-mode 1x40G

set port6-phy-mode 1x40G

set port7-phy-mode 1x40G

set port8-phy-mode 1x40G

set port9-phy-mode 1x40G

set port10-phy-mode 4x10G

set port11-phy-mode 1x40G

set port12-phy-mode 1x40G

set port13-phy-mode 1x40G

set port14-phy-mode 4x10G

set port15-phy-mode 1x40G

set port16-phy-mode 1x40G

set port17-phy-mode 1x40G

set port18-phy-mode 1x40G

set port19-phy-mode 1x40G

set port20-phy-mode 1x40G

set port21-phy-mode 1x40G

set port22-phy-mode 1x40G

set port23-phy-mode 1x40G

set port24-phy-mode 1x40G

set port25-phy-mode 1x40G

set port26-phy-mode 1x40G

set port27-phy-mode 1x40G

set port28-phy-mode 4x10G

end

In the following example, a FortiSwitch 1048E model is configured so that each port is split into four subports of 25 Gbps each.

config switch phy-mode

set port-configuration 4x4x25G

set port49-phy-mode 4x25G

set port50-phy-mode 4x25G

set port51-phy-mode 4x25G

set port52-phy-mode 4x25G

end

In the following example, the FS-T1024E model is configured so that each port is split into four subports of 25 Gbps each.

config switch phy-mode

set port25-phy-mode 4x25G

set port26-phy-mode 4x25G

end

The system applies the configuration only after you enter the end command, displaying the following message:

This change will cause a ports to be added and removed, this will cause loss of configuration on removed ports. The system will have to reboot to apply this change.

Do you want to continue? (y/n)y

To configure one of the split ports, use the notation ".x" to specify the split port:

config switch physical-port

edit "port1"

set lldp-profile "default-auto-isl"

set speed 40000full

next

edit "port2"

set lldp-profile "default-auto-isl"

set speed 40000full

next

edit "port3"

set lldp-profile "default-auto-isl"

set speed 40000full

next

edit "port4"

set lldp-profile "default-auto-isl"

set speed 40000full

next

edit "port5.1"

set speed 10000full

next

edit "port5.2"

set speed 10000full

next

edit "port5.3"

set speed 10000full

next

edit "port5.4"

set speed 10000full

next

end

Configuring forward error correction

You can set the forward error correction (FEC) state on the 25G ports of the FS-1048E and FS-3032E models with the following commands:

config switch physical-port

edit <split_port_name>

set fec-state {cl74 | detect-by-module | disabled}

end

You can set the FEC state on the 100G ports of the FS-1048E and FS-3032E models with the following commands:

config switch physical-port

edit <split_port_name>

set fec-state {cl91 | detect-by-module | disabled}

end

Use the diagnose switch physical-ports list <port_name> command to verify the current FEC state.

Starting in FortiSwitchOS 6.4.0, cl74 is enabled as the default setting for 25G ports, and cl91 is enabled as the default setting for 100G ports.

Starting in FortiSwitchOS 7.0.0, by default, the 25G and 100G ports of the FS-1048E and FS-3032E models now automatically detect whether FEC is supported by the module.

Starting in FortiSwitchOS 7.0.1, you can use the set fec-state detect-by-module command to allow split ports of the FS-1048E and FS-3032E models to automatically detect whether forward error correction (FEC) is supported by the module.