The routing problem is typically solved using a two step approach: Global Routing
• Define the routing regions.
• Generate a tentative route for each net.
• Each net is assigned to a set of routing regions.
• Does not specify the actual layout of wires.
Detailed Routing
• For each routing region, each net passing through that
region is assigned particular routing tracks.
• Actual layout of wires gets fixed.
• Associated subproblems: channel routing and
switchbox routing.
Hi
Actually the layout area is divided on bins and the tool then calculates the no of tracks crossing the bin for congestion analysis and if the routing channels demanded < channels available , then we say the region is congested.