Why Is Network Troubleshooting So Hard?

Issues such as network failure and network slowness commonly result in a troubleshooting process that is extremely complex and long.  This is because:

• Network problems are notoriously invisible

Network problems require extensive reasoning, but existing technology doesn’t provide engineers the visual help required for this inductive process.

• A lot of inter-dependency exists inside most networks, and it is difficult to decode

A simple connection between a PC and a mail server could depend on over two dozens of variables configured properly. This dependency will mushroom once performance requirements are taken into account.

• It is hard to document the historical activities in a network and make them reference-able during troubleshooting

When a network problem occurs, human reasoning typically starts with the question of “what has changed since the last known good state of things?” A stack of static diagrams or documents can’t answer that question.

More often than not, it takes a hero to fix network problems.

The Advantage of 3-Step Map-Driven Network Troubleshooting

Map-driven network troubleshooting is a new methodology based on NetBrain’s SmartMap technology. It has three steps:

3-Step Troubleshooting Methodology (MPH):

Step1: Map Problem Areas	The ability to see problem areas is half the battle. The SmartMap is a new network diagramming technology that can build a fully annotated network map around problem areas on-the-fly. The diagram below maps out the traffic path for a slow web transaction.  Check out more ways to Map Out Problem Areas.
Step2: Probe Live Network via HeatMap	Like X-ray pictures to doctors, HeatMaps provide a diagnostic view that enable network professionals to look into the live network and discover performance hotspots. Learn more about What HeatMaps Can Do.
Step3: Historical Comparison	The question of what has been changed in your network can now be thoroughly answered. NetBrain backend processes will periodically baseline network information such as topology, configuration files, routing tables, and CAM tables.  This information can then be referenced at any moment during the troubleshooting process to instantly discover the differences between the current network and historical baseline. Find out what other kinds of Comparative Analysis NetBrain can do on-the-fly.

The key advantage of map-driven network troubleshooting is making network problems and the entire troubleshooting process visual. With the ability to clearly envision a problem or process and readily access relevant data, the propensity to reason quickly comes naturally.

Another advantage of the map-driven methodology is to facilitate problem escalation and enable collaboration. Dynamic network diagrams have the capability to embed user data and encapsulate troubleshooting processes. Instead of writing up pages of text to describe a problem and its symptoms, one dynamic network diagram (SmartMap) attached to an email will carry all necessary information.

How SmartMap Technology Works

Map-driven network troubleshooting starts with a map and ends with a map, whether the problem is resolved or escalated to other team member. The map used here is not a standard network diagram, but a dynamic network diagram. What makes the SmartMap smart and capable of handling complex troubleshooting requirements is the underlying data model composed of Smart Objects built for each network device.

A Smart Object inside a dynamic network diagram looks similar to a normal network device icon, except that the Smart Object has hundreds of attributes and can interact with both the virtual and live network during troubleshooting. In fact, these same Smart Objects drive full-scale network simulation as well.

This table shows the key capabilities of Smart Objects related to troubleshooting:

Smart Object Capabilities			Use Cases for Troubleshooting
Etc…	Virtual	Built-in logical and physical neighbor relationship	Map problem areas by extending neighbors from one device
		Decoded configuration	Reveal network design behind problem areas. Over 100 design-related parameters are decoded
		Routing table awareness	Map L3 traffic flow based on historical data. Understanding routing propagation
		CAM table awareness	Map L2 traffic flow; Modeling L2 forwarding behavior
	Live	Retrieve performance data via SNMP	Probing live network for potential hotspots; Discover live traffic flow
		Use Telnet/SSH to access device’s command line interface	Automate data collection of show-commands
		Recurring network benchmark	Take a snapshot of the live network for a baseline; Discover network changes
		Ping/Trace live network from multiple proxy points	Probe network connectivity from strategically deployed proxy points

Top-10 Features for Network Troubleshooting

Among hundreds of features related to network troubleshooting, the following 10 are most frequently used by real-world troubleshooters.

	Frequently Used Features	Sample Use Case
1	Real-time map of traffic flow	Troubleshoot a slow application
2	Performance Diagnosis with HeatMap	Discover over-utilized links or excessive delay quickly
3	Discover changes of configuration and routing table around problem areas	Troubleshoot outages caused by network changes
4	Search and map the search results	Map out problem areas with simple inputs such as an IP address or hostname
5	Automate show-command execution across multiple devices without scripting	Take a snapshot of the network before problem escalation
6	L2 connectivity mapping	Discover the switch port any PC is connected to
7	Measure advanced performance metrics such as delay, jitter and packet loss via IPSLA	Troubleshoot VoIP voice quality
8	One-click login to any device	Automatically Telnet/SSH to a network device without typing username and password
9	Top-talker drill down across a live link	Discover the malicious traffic that hogs a WAN link
10	Routing table analyzer	Discover an unstable routing entry

See It in Action

The following network troubleshooting guide is to showcase how map-driven troubleshooting can significantly shorten the time to resolve an outage. It is worth noting that although there are only a few cases listed, the troubleshooting methodology is applicable to most network troubleshooting scenarios.

• Troubleshoot Routing Protocol
• Troubleshoot BGP
• Troubleshoot OSPF
• Troubleshoot EIGRP
• Troubleshoot RIP
• Troubleshoot Static Route
• Troubleshooting VoIP
• Troubleshoot Data Center Connectivity
• Troubleshoot Multicasting
• Troubleshoot Slow Application