92CHAPTER 4: DISCOVERING THE NETWORK

Key Concepts

The discovery process can be initiated in a number of ways detailed later

 

in this chapter. This section explains the key concepts behind the

 

discovery process itself.

 

The process is divided into two distinct operations – detecting the devices

 

that exist on the network (discovering devices), and subsequently

 

establishing how they are physically connected together (determining

 

topology). Both of these operations are divided further into several

 

stages. The main concepts associated with these operations and

 

associated stages are outlined in this section as follows:

 

How 3Com Network Director discovers devices on the network

 

How 3Com Network Director determines the network topology

 

How 3Com Network Director re-discovers information about a

 

network it already knows about

 

How scheduled discoveries work

The Discovery Process This operation determines which devices exist on one or more IP subnets.

Detecting Devices It also finds out more about each discovered device, such as its type and capabilities. The operation is initiated with a list of subnets to discover. Within each subnet 3Com Network Director attempts to locate devices across one or more specific IP ranges. You can control the ranges of devices to be detected within each subnet, but the default behavior is to attempt the full range for each subnet. Fine-tuning the discovery process, including specifying subnet ranges, is described later in this chapter.

The detecting devices part of the discovery process consists of a number of discrete stages:

1IP Ping

2Device Capability Detection

3SNMP Type Detection

4IP to MAC Resolution

5End Station Type Recognition

6Web Type Recognition

7DNS Name Resolution

8NBX Phone Detection