Description
This article describes how to enable Jumbo frames on the FortiSwitches that are managed by the FortiGate (via FortiLink).
Scope
FortiGate v6.4, v7.0, v7.2.8 and v7.4, FortiSwitch: v6.4, v7.0, v7.2.3 and v7.4.
Solution
- Enable Jumbo frame on the FortiLink interface:
config system interface
edit "fortilink"
set mtu-override enable
set mtu 9000
next
end
The MTU will be valid for all the VLANs defined within the FortiLink interface.
- Make sure that all the physical ports are configured with max frame size where JUMBO frames are required. This needs to be enabled on the ports that are part of the FortiLink trunk and the ports where the server or SAN devices are connected.
The following setting needs to be configured on the switch side, because the switch side calls the FortiLink trunk, and the FortiGate calls the FortiLink interface.
config switch physical-port
edit "port1"
set max-frame-size 9216
set speed auto
set status up
set storm-control-mode disabled
next
end
- Configure the internal interface with a static IP address to enable the MTU override option. Then set the MTU as 9000.
config system interface
edit "internal"
set ip 10.255.1.3 255.255.255.0
set allowaccess ping https ssh
set type physical
set snmp-index 58
set mtu-override enable
set mtu 9000
next
end
After completing step 3, reboot the FortiSwitch for the changes to take effect on all the configured VLANs. (This is mandatory).
Verification for jumbo frames:
Create a VLAN called JUMBO: 192.168.15.1/24 under the FortiLink interface. Make sure to enable the Ping under the VLAN settings:
config system interface
edit "JUMBO"
set vdom "root"
set ip 192.168.15.1 255.255.255.0
set allowaccess ping
set device-identification enable
set role lan
set snmp-index 49
set ip-managed-by-fortiipam disable
set interface "fortilink"
set vlanid 301
next
end
Next a virtual interface was created on the FortiSwitch with the same name as shown below:
S648FFTV23-----5 (JUMBO) # show
config system interface
edit "JUMBO"
set ip 192.168.15.10 255.255.255.0
set snmp-index 65
set vlanid 301
set interface "internal"
next
end
Setting up the ping options with data size 8960 and df bit set to yes:
With these settings:
S648FFTV23-----5 # execute ping-options data-size 8900
S648FFTV23-----5 # execute ping-options df-bit yes
S648FFTV23-----5 # execute ping-options view-settings
Ping Options:
Repeat Count: 5
Data Size: 8960
Timeout: 2
Interface: auto
Interval: 1
TTL: 64
TOS: 0
DF bit: set
Source Address: auto
Pattern:
Pattern Size in Bytes: 0
Validate Reply: no
Adaptive Ping: disable
S648FFTV23-----5 # execute ping 192.168.15.1
PING 192.168.15.1 (192.168.15.1): 8960 data bytes
8968 bytes from 192.168.15.1: icmp_seq=0 ttl=255 time=0.5 ms
8968 bytes from 192.168.15.1: icmp_seq=1 ttl=255 time=0.4 ms
8968 bytes from 192.168.15.1: icmp_seq=2 ttl=255 time=0.4 ms
8968 bytes from 192.168.15.1: icmp_seq=3 ttl=255 time=0.4 ms
8968 bytes from 192.168.15.1: icmp_seq=4 ttl=255 time=0.3 ms
--- 192.168.15.1 ping statistics ---
5 packets transmitted, 5 packets received, 0% packet loss
round-trip min/avg/max = 0.3/0.4/0.5 ms
Reference articles:
