An important part of Layer 2 Network Discovery is understanding the different methods by which a network can be discovered. There are two Layer 2 Network Discovery methods.
Address Resolution Protocol (ARP) Cache discovery locates network devices by reading SNMP information on your network. This scan type uses SNMP enabled devices (usually routers) to identify devices that are active on your network. In addition to using the ARP cache on each network device, ARP Cache discovery also uses many proprietary discovery protocols to find additional devices connected to the network.
The Discovery Setup wizard prompts you to enter a Seed IP Scope (IP addresses, IP address ranges – including IP subnets) that indicates where you would like the discovery to start. These devices are used as the seed of the network discovery.
Important: We recommend that you use ARP Cache discovery as your primary discovery method.
Ping Sweep discovery scans a range of IP addresses and finds the devices that respond to the ICMP or SNMP protocol.
The Network Discovery Setup wizard prompts you to enter a Seed IP Scope (IP addresses, IP address ranges including subnets) that indicates where you would like to focus your network scan.
Note: The Ping Sweep discovery method is used for very specific discovery scans. If you are unsure of your network configuration, including any of its subnetworks, ARP Cache discovery is a more appropriate method for discovering your network.
For more information about how Seed IP Scopes work in each Layer 2 discovery method, see About Seed IP Scope.
You can acccess the Advanced Discovery Settings dialog using the Advanced button. This dialog sets the maximum number of threads to use during the discovery scan, allows you to configure WhatsConnected to ping devices first, ping discovered subnets, resolve hostnames using a Domain Name System (DNS), and exclude device categories from the discovery scan.
Note: When setting the number of threads used during a scan, increasing the number of threads allows WhatsConnected to simultaneously open more connections with network devices, possibly reducing the time needed to perform the scan, however this may negatively impact network performance as the number of open connections increases.