ISPPlanet Network Management System Series - NetPlus AutoManage

Network Discovery

Use NetPlus Node Discovery (NP_DISCO) (right) to search for SNMP agents in one or more subnets. Unlike some other monitoring products, NP_DISCO does not use ping; devices that do not speak SNMP cannot be discovered or monitored by AutoManage. Each discovered node is added to the NP_DISCO window, labeled by hostname (if entity in database) or IP address (otherwise). NP_DISCO makes creating a topology map child's play. Populating the local database using discovery results would be a great extension.

Discovered nodes can be deleted, renamed, associated with other icons, and organized into hierarchical groups (right). For a snazzier look, apply one of the supplied backgrounds or create your own bitmap—for example, line up nodes in a "LAN" layout.
	Submaps are defined by creating a group icon, then dragging nodes into the group. Right-click on any node or group to display its properties (left). For future reference, maps can be saved and printed.

Once you've created a topology map, NP_DISCO provides color-coded status and trap monitoring (see Monitoring section). For further detail, select a node and use right-click menu items to browse the agent's MIB or view received traps. Other applications can be launched from NP_DISCO by adding them to the Run menu (i.e., editing the .ini file). We added all the other AutoManage applications to our NP_DISCO Run menu, creating a single, integrated entry point into the entire suite.

Device Browse and Query
One primary function of any SNMP network management system is the ability to query configuration parameters and counters. These values are represented as objects in a management information base (MIB). Every device that speaks SNMP version 1 supports the basic Internet MIB defined by RFC 1213. A large collection of standard and enterprise MIBs have been defined for other resources. For example, in our ISP-Planet evaluation of web caches, we used a Squid MIB to query this popular open source cache.

Because every network is different and administrators have different concerns, SNMP managers must be extensible, easily accommodating new MIBs (right) . The NetPlus MIB Compiler (NP_MIB) can be used to add new MIBs to AutoManage. Compiled versions of the RFC 1213 MIB and a few other standard MIBs are included by default. To other MIBs, just specify source, destination, and description file names.

But be careful not to overwrite existing destination or description files like we did—source files are not included with the distribution. We had success with every MIB we tried to compile, except one: compiling the Squid MIB caused NP_MIB to fault. According to ACE*COMM, the culprit was lack of white space immediately before the Squid MIB's END statement. The NP_MIB parser will be updated to handle this legitimate syntax in a future release.

Three AutoManage applications are available to query SNMP agent MIBs. NetPlus MIB Walker (NP_WALK) generates SNMP GET-NEXT requests to "walk" through all objects known to an agent (left). This can be handy to discover objects supported by the agent—particularly enterprise extensions. To use NP_WALK, start by selecting an entity and context.

 

When looking for a specific object or set of objects, you'll find NetPlus MIB Browser (NP_BROWZ) or NetPlus MIB Table Grabber (NP_TABLE) more convenient. Use NP_BROWZ to get scalar objects or NP_TABLE to get tabular objects (below, left) . Select an entity, a context, and one or more MIB variables to query. AutoManage issues the series of SNMP GET or GET-NEXT requests needed to retrieve these object values, then displays the result (below, right). Queries can be saved for reuse and results can be printed, saved to a text file, or recorded in an ODBC database.

go to Part 3: Device Control / Network Monitoring