Part Iii. Zoneranger Services; Chapter 19: Discovery - Tavve zoneranger User Manual

Part III. ZoneRanger Services

Chapter 19: Discovery

Populating the ZoneRanger Database
Most ZoneRanger management services as well as proxy services for non-SPX ZoneRanger models
require the ZoneRanger database to be populated with information about the entities that the
ZoneRanger is intended to manage, such as nodes, interfaces, and TCP ports.
The process of analyzing the network and populating the ZoneRanger database is called discovery.
The process can range from a simple analysis to identify interfaces and subnets associated with a
predefined set of configured seed nodes, to an aggressive search for network device information,
combining techniques such as seed node analysis, ping range sweeps, ARP cache and route table
searches, broadcast pings, and root cause path analysis.
The extent and aggressiveness of the network analysis that is performed is based on a variety of
configuration options. This chapter describes how discovery is configured and executed on a
ZoneRanger.
The ZoneRanger database is organized into tables based on the types of entities that can be
discovered, such as nodes, interfaces, subnets, and TCP ports. The database also includes
relationships between entities, for example, the interfaces and TCP ports associated with a node, the
interfaces on a given subnet, and so on.
ZoneRanger discovery is an automated process that can be invoked manually as needed, or
configured to run periodically. The first time discovery runs on a ZoneRanger, the database is
populated based purely on the results of analyzing configured seed nodes and ping ranges. On
subsequent discovery runs, existing database content is merged with new discovery results so that
existing entities are updated with any changes, and new entities can be added to the database.
The Discovery Algorithm
To understand the various discovery configuration options, a simplified overview of the discovery
algorithm is helpful. The ZoneRanger discovery algorithm comprises two main types of activity:
•
Accumulating addresses (that is, building a list of entity addresses to analyze)
•
Analyzing addresses (that is, analyzing the entity addresses in the list).
The simplest way to accumulate addresses is to configure seed nodes and ping ranges. Configured
seed nodes are automatically added to the list of addresses to be analyzed. Any addresses in a
configured ping range that pass the include network/exclude network filter criteria and respond to a
ping are also added to the list of addresses to be analyzed.
The primary purpose of analyzing addresses is to identify nodes, interfaces, subnets, and TCP ports,
and the relationships between these entities, to populate the database.
In addition, depending on configuration options, additional addresses may be discovered while
analyzing addresses:
•
In the interface table of a device
•
In the ARP cache of a device
•
In the route table of a device
•
As the result of entities responding to broadcast ping requests
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