Best Practices Series: Network Discovery

Network discovery is, not surprisingly, the process of finding and identifying every device, server and system on your network. Mastering IT best practices around network discovery will greatly improve how you map and monitor your IT infrastructure.

Networks these days are more dynamic than their predecessors. Tracking everything on your network manually is absolutely not realistic. For starters, just think about the changes that virtualization and live migrations have brought forth.

Instead, IT pros need to have up-to-date network inventory based upon discovery and asset management – from the physical to the virtual.

Three Tools for Network Discovery

The most three common tools for continuous network discovery include the following:

• SNMP (Simple Network Management Protocol): As the leading technology used for network management, most network devices are SNMP-enabled. By using supporting technology, SNMP allows organizations to accurately understand every SNMP-enabled device on the network, as well as their impact
• Ping: Perhaps the most well-known discovery tool, manually pinging network servers was once a regular part of an sysadmin's job. These days, automated systems ping different network devices to understand their status and verify they’re online
• ARP (Address Resolution Protocol): ARP makes use of SNMP to query the cache of a device, which can then build a new database of MAC addresses based on what it discovers. This process allows for discovering neighboring devices and eventually forms a comprehensive view of the network

One best practice for network discovery is to use a solution that leverages all three of these technologies to accurately and consistently determine what’s connected to the network. Conveniently enough, our own network monitoring solution makes use of all three. This includes SNMP Smart Scan, Ping Sweep and ARP Cache Discovery, among others, to provide IT pros with real-time network discovery.

Explore Your Own Network Topology

Network efficiency is an endless pursuit for IT pros. Generating and exploring network topology maps is a best practice aimed at optimizing efficiency by gaining a deeper understanding of the network.

Virtualization and the prevalence of connected mobile devices create a constantly shifting landscape that’s hard to monitor. That’s why automatic network discovery is vital for accurate monitoring. It identifies and corrects bottlenecks that might be restraining your network and application performance.

Layer 2 and Layer 3 discovery methods should be employed to identify every device and its role. Layer 2 protocols are used to discover interconnecting links and port-to-port connectivity, while Layer 3 protocols help discover neighboring devices.

One efficient Layer 3 solution is management software that queries SNMP-enabled devices, then builds an internal database based on the information it discovers. It’s able to build an accurate network map, including device location, attributes and key role.

Another Layer 3 solution is to use active probes that scan through the network and transmit device data back to a tool using a different and secure channel.

Don’t Neglect Link Layer Discovery Protocol

While Layer 3 discovery methods are needed for dynamic networks, Layer 2 protocols have a tendency to be proprietary. Examples include Cisco CDP and Nortel NDP. These different protocols make Layer 2 discovery difficult. As such, the Link Layer Discovery Protocol (LLDP) was created to streamline discovery in these situations.

We recommend enabling LLDP globally on your network to standardize topology. This is vital for businesses with multi-vendor networks. LLDP protocols provide crucial device information to neighboring devices, which is useful to Layer 3 discovery protocols.

WhatsUp Gold network monitoring software uses LLDP and SNMP, along with ARP Cache discovery, to move through every interconnected device and form a comprehensive view of everything on the network, even if there has been no recent traffic or the device is in a blocked state.

IT managers who yearn for automatic discovery of their networks hopefully should benefit from these best practices. In our next blog about best IT practices, we’ll look at network mapping. Discovery and mapping work hand-in-hand, making understanding both a powerful asset.