The Juniper Devices default polling group is used by Network Protocol Manager for IS-IS to monitor the availability of IS-IS sessions (IS-IS adjacencies). Network Protocol Manager for IS-IS monitors the availability by monitoring the ISISInterfaces that are discovered on Juniper devices.
Because the standards-based IS-IS MIB (defined in RFC 1195) is used by Juniper devices, Network Protocol Manager for IS-IS uses SNMP to discover and monitor IS-IS topology for Juniper devices. The Juniper Devices polling group uses SNMP polling to monitor IS-IS sessions by monitoring the ISISInterfaces on the discovered Juniper devices.
The Juniper Devices polling group has a default setting and an optional setting:
ISIS JUNIPER SNMP Setting (default)
ISIS EXTERNAL Setting (optional)
The two settings are mutually exclusive, which means that only one or the other (but not both) can be specified for a Juniper Devices polling group at any given time.