Network Management

Network Selection Discovery options

You can specify the range of IP addresses you want to discover with the NTM Discovery wizard. After IP nodes are discovered, you can select which ones you want to include on your map. The time it takes to complete a Discovery scan relies heavily on the range of IP addresses you specify. This article provides guidelines and steps to create Discovery ranges that will accurately discover the devices you want to map without including a large number of other devices.

First published date

11/9/2018 6:57 PM

Last published date

11/9/2018 6:57 PM

Overview

This article describes how to specify the range of IP addresses you want to discover with the NTM Discovery wizard. After IP nodes are discovered, you can select which ones you want to include on your map. The time it takes to complete a Discovery scan relies heavily on the range of IP addresses you specify. This article provides guidelines and steps to create Discovery ranges that will accurately discover the devices you want to map without including a large number of other devices.

Product section

Network Topology Mapper

Resolution

Detail 

The following lists Network Selection Discovery options from the most specific to the most general option:

Specific nodes 

This option discovers only the nodes you specify by IP address. It is useful when you have an existing map and you want to add a specific node without having to discover a number of subnets or IP addresses. Add specific nodes by their IPv4 address or IPv6 address. Add the one node per line.

Discovery IP ranges 

This option discovers only the nodes you specify by IP address range. The range can be any contiguous IP address block. Multiple ranges can be included to allow for discovery of non-contiguous ranges. Nodes outside the specified range will not be discovered and the Hop Count Discovery option is ignored for IP ranges.

For example, a discovery using the range 10.110.1.1 to 10.110.3.255 defines a contiguous discovery range including all possible IP addresses between .110.1.1 and 10.110.3.255.
 
In contrast, a discovery including the starting address of 10.110.1.1 and the ending IP address of 10.110.2.255 along with an additional range of 10.110.3.1 to 10.110.3.255 will discover only those ranges and will not include the 10.110.2.0 subnet between them.

IPv6 ranges are supported.

Subnets 

This option discovers the specified subnet and all networks directly connected to devices on the specified subnet.
For example, consider a discovery for the 10.110.1.0 subnet with a subnet mask of 255.255.255.0. If the discovery finds a router on the 10.110.1.0 subnet that also has interfaces on 10.10.20.0 and 192.168.5.0 subnets, those subnets will also be scanned for devices and connectivity. Additional subnets connected to those devices on the new subnets are not scanned.

After discovering subnets, clear the checkbox next to a subnet to remove that subnet from your map. IPv6 subnets are supported.

Seed devices 

This option discovers all subnets that the specified device is aware of. By adding hop counts, this option will discover devices several networks away. You can use a seed device to discover subnets, connectivity, and network devices throughout your network. A seed device must be a layer 3 switch or router. NTM will scan the connection to the indicated device and use that information to scan directly connected devices.

 

After discovering directly connected devices, NTM will discover devices on connected subnets to the extent you have indicated in the Number of Hops option.

 

IPv6 see device addresses are supported.