User's Manual

92 CHAPTER 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
– Detecting Devices
This operation determines which devices exist on one or more IP subnets.
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:
1 I
P Ping
2 D
evice Capability Detection
3 SNMP Type Detection
4 IP to MAC Resolution
5 End Station Type Recognition
6 Web Type Recognition
7 DNS Name Resolution
8 N
BX Phone Detection