this information was accurate 6 months ago...

PND is a good product but cannot really be compared directly to either HPOV or CiscoWorks.

Ciscoworks is an element manager, designed exclusively to manage Cisco kit (a bit like Compaq Insight Manager does with CPQ Servers), nothing will get closer to Cisco than Cisco works.

PND sits a level above this (and can integrate to Cisco works for detailed device management), dynamically discovering all IP4 capable devices in an enterprise (PND is an IP only product) and discovering the port-port level connectivity between them using reverse probability algorithms (Peregirne has some reasonable white papers that explain how this works).

This operation gives you a nice clean comprehensive layer 2 inventory in a self contained appliance that can be deployed to a mid sized enterprise (up to around 7500 users) in less than a week.

In terms of network management the product is similarly automated and works entirely by moinitoring traffic either directly or via the interrogation of standard information sources on network managed devices. The product therefore requires no probes and does not operate using SNMP traps, this again allows for rapid deployment and also means you won't get any local utilisation problems because of SNMP trap fault shadowing.

The product can monitor and report on the current status of your network both in terms of device and line breaks as well as more subjective monitoring types such as utilisation and jitter, a service analyser also allows for the analysis of path reliability between two points (a client and a server for example). A timewarp feature is also available to allow predictions of future reliability based upon previous trends.

For larger enterprises, multiple servers can be tied together to allow for a degree of consolidation.

PND will not attempt to get into predictive modelling at all (like Opnet for example), this may be a logical integration for the future for this type of product.

HPOV is typically a level above PND, as a multi-protocol enterprise network management system HPOV would often take fault alerts via integration from products such as PND, allowing for an effective high level enterprise management view without the pain of using resource intensive data gathering mechanisms (probes).

If you are a smaller enterprise <2500 users and are based entirely on TCP-IP then PND may well be all the network management technology you ever need. Larger users may use PND in order to create an automated 'middle-tier' in their network management model.

hope this helps