Fortigate 80F slow upload when connected at 1Gigabit, not with 100Mbit

[thijsoft]

Fortigate 80F, connected to 250MBit internet connection.

When using Gigabit connection, the upload speed to internet is slow, maximum 25Mbit average

When connection is made with 100Mbit switch there is no problem! 100MBit upload can be reached.

Tested with several switches and direct PC connections.

Fortigate support does not have direct solution for me, can anybody help?

[Toshi_Esumi]

First thing I would check is the uplink device's link status if it's matching with the 80F's. On 80F side, you can use "diag hard deviceinfo nic <port_name>" to see like below.

========== Link Status ==========
Admin :up
netdev status :up
autonego_setting:1
link_setting :0
speed_setting :10
duplex_setting :0
Speed :1000
Duplex :Full
link_status :Up

Toshi

[thijsoft]

Hi Toshi,

I check it:

Admin :up
netdev status :up
autonego_setting :1
link_setting :1
speed_setting :1000
duplex_setting :0
Speed :1000
Duplex :Full
link_status :Up

Settings seems to be ok. When connecting any device direct or with networkswitch at 1Gbs, the upload speed at the internet is slow. When connecting at 100Mbit, I can reach 100Mbit. I also tested with PC direct to Fiber connection (fixed IP configured at LAN settings), I can reach the maximum of 250Mbit up and down (wich the specs are of this connection).

[Toshi_Esumi]

I wouldn't rule that one out until I can get in the uplink device and check what it decided when it's connected to the 80F, which could be different when it's connected to other devices. Although the chances are low. If it's capable, I would check the log in the uplink device if any errors are recorded.

If uplink side is half duplex for example, download direction wouldn't have any problem while upload direction loses lots of packets due to collisions. That's why I would want to rule this out first.

You mentioned about several switches. Did it mean you tested like vendor_modem<->switch<->80F vs. vendor_modem<->80F? If not, the result might be different.

Toshi

[thijsoft]

The problem is that if the Lan ports on the 80F are operating at 1GBit, the upload speed to internet is slow. Around 20 / 25 Mbit. If the 80F lan port is operating at 100Mbit, the upload speed reaches 100Mbit also.

Tested with other vendor firewall/router, there is no problem.