Historical Comparison – Step 3 of Map-Driven Network Troubleshooting

During the troubleshooting process, the most important question is: “What has changed since the last time that the network was running properly)?”

Unfortunately, this question is not easy to answer for most networks. With the exception of configuration files, most networks lack any other baseline data that real-time troubleshooters can utilize for comparison purposes.  For example:

• There is no routing table baseline
• There is no traffic flow baseline
• There is no topology (L2 or L3) baseline

NetBrain not only provides recurring baseline capabilities for all of the above, it also parses the results of baseline comparisons and provides comparative analysis for troubleshooters. Take a routing table as an example, NetBrain will first baseline all routing data and parse every routing table field such as next hop, metric, etc.  During troubleshooting, NetBrain will compare routing tables field by field, filtering unimportant fields and revealing what’s been changed. (Note: route age is not considered during comparison)

A list of map-based comparative analysis scenarios:

Sample Comparative Analysis Scenario	Helpful NetBrain Capabilities
Configuration files change	Highlight specific lines of configuration that are different
Routing table change	Discover routing change by routing table fields, e.g. next hop or metric
Traffic path change	Map out current or historic traffic flow between two end points
L3 network topology change	Annotate in a L3 map for any topology change
L2 network topology change	Discover switch-to-switch connectivity change
L2 network connectivity change	Discover any end host added or removed from any LAN segment