When choosing between NNMi and DDMa for Layer 2 discovery, NNMi is the preferred route. HP considers NNM to be the authoritative source for Layer 2 objects. NNMi performs continuous discovery more stable and with less administrative intervention, then DDMa jobs. NNMi discovery engine filters out node for which not enough information is present (for example, if only MAC address is known), thus creating more clear and applicable topology.
There are two methods for integrating NNMi topology into BSM/UCMDB:
- NNMi – BSM topology integration;
- NNMi – UCMDB integration.
HP recommends using the NNMi - BSM topology integration method. The other integration method which uses the Data Flow Probe (formerly called DDM Probe) is still supported, but it is used more for backward compatibility with older product versions (for example NNMi 8.11+ and UCMDB 8+).
Comparison of these two methods.