The first step is to define SNMP communities if you are using a non-public community.
1. From the FusionInventory interface in GLPI, click Network 1 then SNMP Authentication 2.
2. Click + 1 to declare a community.
3. Give a name to the switch 1, select the version 2 then enter the name of your community 3 and click on Add 4.
4. The community is added 1.