Network Diagramming Channel Feature

Using Diagramming for Troubleshooting Network Issues with OPNET's NetMapper Spanning Tree

By Amanda Ciccatelli
TMCnet Web Editor

When network engineers create diagrams, they usually have a limited amount of time do this tedious task. They attempt to create a physical topology diagram and put as much logical information into it as possible in a short period of time.

“You try to create a single diagram that fits all needs,” Ankit Agarwal, associate vice president of engineering at OPNET told TMCnet in an exclusive interview.

Unlike its competitors, OPNET NetMapper’s Spanning Tree creates logical diagrams, not only physical diagrams. As the name suggests, Spanning Tree creates a tree, so there is a path from every node to every other node along that particular tree, said Argarwal.

When you are troubleshooting a particular protocol, it is essential to see the network in terms of that protocol. For instance, if you have Spanning Tree running in your network, there are specific constructs in Spanning Tree that are very important pay close attention to.

 “For performance and efficiency reasons, network engineers decide ahead of time where the root of that tree is going to be, which is typically called a root bridge,” Agarwal explained.

The Spanning Tree diagram uses operational data from the network to point out the location of the root of the tree, which means that all the traffic is ultimately going to flow through that node as it goes to different areas of the Spanning Tree.

“Sometimes customers will add a new switch to the network and the switch will not be configured absolutely correctly,” he explained. “So, instead of the root bridge being in the core of the network, some other low powered switch at the edge of the network will by mistake become the root bridge because its settings are configured differently and incorrectly, and all of your traffic will start to flow through the low powered switch and it starts to slow things down.”

NetMapper’s Spanning Tree diagram would point out this problem. Spanning Tree would see the root bridge as well as what path it could start taking through the network to that root bridge. Also, it wouldn’t be so cluttered with other information that has no impact on Spanning Tree.

“These logical diagrams really help with the troubleshooting aspect and are unique to NetMapper,” Agarwal said.

In These problematic situations, the user simply has to do an App Network Path and see where the path takes them, according to Vinod Jeyachandran, vice president of engineering, and product manager at OPNET. If a switch is found, then the user can look at another cross section of the network, which would be done with Spanning Tree.

Jeyachandran said, “By taking a look at Spanning Tree you find out what went wrong. Having this view that not only tells you how the network is connected, but to slice it into different cross sections to see the traffic, becomes more important.”

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