When using auto detection the SFP ports on LANCOM switches can only detect the SFP module. No negotiation is done between the two connected switches. If for example a switch with a 10 GBit SFP+ module is connected to a switch with a 1 GBit SFP module the link cannot be established. Therefore the link speed must be set to a fixed value (the same value on both switches).
This article describes how the speed for the SFP ports can be set on GS-23xx, GS-3xxx or XS-51xx series switches.
Make sure, that access to the management IP address of the device is possible via another or an additional port. If a connection via the SFP port cannot be established, access to the switch is still possible.
The port configuration has to be made before plugging in the SFP module.
Go to the menu Configuration → Port → Configuration and set the speed for the SFP port (ports 23 - 26) under Speed - Configured.
1) Go to the menu System → Port Management → Port Configuration.
2) Set the speed for the used SFP port under Mode (ports 25 - 28).
1) Go to the menu System → Port → Summary → Port Summary and click the checkbox of a SFP port (ports 1 - 8) to edit its settings.
2) Check the checkbox Speed and select a port speed.