Discovery and Data Synchronization

As network administrators add, delete, or modify devices on a network, regional servers, such as regional1 and regional2, discover those changes and update global servers, such as global1 in the example in this chapter, regional1 and regional2 also notify global1 of changes that administrators make to the management mode of a node it manages.

Any time global1 requests information about a node that is managed by regional1 or regional2, regional1 or regional2 responds to global1 with the requested information. global1 never talks directly to a node. There will not be duplicate SNMP queries to devices when global1 performs a discovery.

global1 synchronizes with regional1 and regional2 each time regional1 or regional2 completes a discovery. NNMi uses FDB (Forwarding Database) data to calculate layer 2 connections. FDB data is very dynamic, and varies a lot between discoveries, especially if there are multiple regionals connected to a global.

The Rediscovery Interval is adjustable on each regional, and can make a difference in the discovery accuracy between global1 and the regional managers. The shorter the Rediscovery Interval, the more accurate the discovery, and the more NNMi-generated network traffic. The longer the Rediscovery Interval, the less accurate the discovery, and the less NNMi-generated network traffic. This means that the larger your network grows, the less frequently you might want to rediscover. To set the Rediscovery Interval, do the following steps:

1. From the regional1or regional2NNMi console, click Discovery Configuration in the Configuration workspace.

2. Adjust the Rediscovery Interval according to your how often you want the regionals to initiate a discovery. The global will initiate a discovery immediately after a regional completes a discovery.

3. Click Save and Close.