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Visualizing & Analyzing

This is the heart of Topolograph: an interactive OSPF/IS-IS graph you can probe with the same algorithms the routers use. Everything below runs against your uploaded snapshot, so experiments never affect the production network.

Shortest paths

Pick a source and a destination node and Topolograph builds the shortest path tree between them, highlighting the path(s) and showing the total IGP cost.

Shortest path tree between two nodes

When multiple equal-cost paths exist, ECMP is shown explicitly so you can see where traffic load-balances.

Topology with ECMP paths

Backup paths

Topolograph doesn't just show the primary path — it computes the backup path the network would actually use if the primary failed, including secondary backups. This answers the question every change-window raises: "if this link goes, where does the traffic go?"

Backup shortest path tree

When you reason about capacity during a failure, all links are counted, whether or not they belong to an ECMP set.

Simulating failures

Test "what if" scenarios without changing anything on the live network.

First make sure you are in failure-reaction mode: switch from the general view to the Network reaction to failure tab. On that tab a left-click on a link changes behaviour — each click simulates an adjacency going down / the link being removed from the graph. Topolograph recomputes paths instantly and shows how traffic re-routes around it.

Network reaction to removing a link

You can see the result together with statistics on the recalculated paths:

Network reaction to a removed edge, with stats

Shut a node

Simulate an entire router failing and watch traffic flow around the failed node. Right-click a node and choose Shutdown this node.

Network reaction to shutting a node

Result after shutting a node

Change an IGP metric on the fly and immediately see the effect on path selection — ideal for planning network work, draining traffic off a link, or checking a metric before applying it on the real network.

Make sure you are still on the Network reaction to failure tab. Right-click a link: a form listing the links appears. Set a new metric value next to the link you need — the re-routing result shows on the graph immediately.

Network reaction to an OSPF cost change

Network Heatmap

The Network Heatmap (under Analytics) reveals structural properties of the topology at a glance — which links and nodes carry the most paths, where your single points of failure are, and which networks have no backup path.

Network heatmap with networks

Nodes marked red carry the most networks with no backup path.

Choose None backuped networks to see networks with a single termination point: they attach to only one device, so if that device fails they become unreachable.

Heatmap highlighting non-backed-up networks

Detecting asymmetric paths

Routing that takes one path forward and a different path back can complicate firewalls, QoS and troubleshooting. Topolograph's Analytics → Asymmetric paths report finds these pairs for you.

Analytics menu — asymmetric paths

A real asymmetric path example

Where to go next