Subsequent discovery

During a subsequent discovery, the MPLS Topology Server conducts a full-scope discovery on PE and P devices, but does not conduct a full-scope discovery on Multi-VRF CE or CE devices. Instead, the MPLS Topology Server conducts an SNMP discovery of just VRFs on Multi-VRF CE and CE devices.

If the MPLS-BGP cross-domain correlation feature is enabled, the MPLS Topology Server also conducts an SNMP discovery of exterior BGP (eBGP) sessions on Multi-VRF CE and CE devices.

Of course, as in previous releases, the MPLS Topology Server performs a subsequent discovery in accordance to the following algorithm:

• Performs a topology synchronization with IP Availability Manager and compares the current IP Availability Manager topology with the previously imported topology.

• Conducts discovery only on new devices, or on known devices that have a newer discovery timestamp.

  For a new device or a known PE or P device that has a newer discovery timestamp, the MPLS Topology Server conducts a full-scope discovery on the device.

  For a known Multi-VRF CE or CE device that has a newer discovery timestamp, the MPLS Topology Server conducts an SNMP discovery of just VRFs on the device.