Some standard MIBs assume that a particular SNMP entity contains only one instance of the MIB. Thus, the standard MIB does not have any index that allows you to directly access an instance of the MIB. In these cases, a community string indexing is provided to access each instance of the standard MIB. The syntax is [community string]@[instance number].
For example, the Catalyst switch includes one instance of the standard BRIDGE-MIB for each VLAN in the switch. If the read-only community string is public and the read-write community string is private, you can use [email protected] to read the BRIDGE-MIB for VLAN 25 and use [email protected] to read and write the BRIDGE-MIB for VLAN 33. If just public or private is used, the BRIDGE-MIB for VLAN 1 is accessed.
For SNMPV3 there are NO community strings. So the question is: how do we access the bridge mib for VLANs? Currently, when using SNMPV3, we only see the entries on VLAN 1.