Technical Tip: Intermittent connection on SFP+ port manually negotiated at 10GB

[GGMACHAIN]

Description	This article indicates the settings to be made to avoid flaps in the SFP+ interface manually negotiated at 10GB.
Scope	FortiGate 7.4.x.
Solution	SFP+ interfaces randomly turn down or turn up when manually negotiated at 10 GB, as shown in the event logs below. First, confirm the type of transceiver in use and the configuration applied to the interface. The following command can be used to identify the transceiver mode: get system interface transceiver x2 Interface x2 - SFP/SFP+/SFP28, 10GBASE-LR The output above indicates that the transceiver in use is of the 10GBASE-LR type. Therefore, confirmation of the media type configured on the interface is required, as it must match the transceiver type to avoid the observed issues. If the media type is negotiated differently, connectivity problems may occur. The command below displays the configured media type of the interface: show system interface x2     set type physical     set mediatype sr     set speed 10000full Note: A mismatch between the configured media type and the transceiver can disrupt connectivity. A common scenario occurs when the transceiver is LR while the interface is configured as SR, causing links to remain down or fail to pass traffic. Workaround: A temporary workaround consists of manually configuring the interface speed to 1 Gbps to mitigate link flapping. Another workaround consists of manually configuring the media type to match the transceiver type in use.