Table of Contents
What is the difference between global routing and detailed routing?
Global routing first partitions the routing region into tiles and decides tile-to-tile paths for all nets, whereas detailed routing determines the exact tracks and vias for nets.
What is global route in VLSI?
Global routing in VLSI (very large scale integration) design is one of the most challenging discrete optimization problems in computational theory and practice. The algorithm ensures that all routing demands are satisfied concurrently, and the overall cost is approximately minimized.
What is meant by global routing?
Global routing is done to provide instructions to the detailed router about where to route every net. It provides the channels for interconnect to be routed. Detailed routing is where we specify the exact location of the wires/interconnects in the channels specified by the global routing.
What is Grided and Gridless routing?
Grid based and gridless routing: Routing takes place along the grid lines. The space between adjacent grid lines is called wire pitch and is equal to sum of minimum width of wires and spacing of wires. On the other hand, any model that does not follow grid based routing is termed as gridless routing model.
What is the global routing table?
The global routing table is a database maintained by IP on the switch route processor (SRP) module. It contains at most one route per protocol to each prefix in the table. It might also have a BGP route to the prefix, and a RIP route to the prefix, but no more than one route to a prefix per protocol.
What is routing track in VLSI?
User interface / operation. Layout space: Total number of routing paths, wiring cut-outs or routing ranges that run through a connection routed in the layout space.
How many routes are there in global routing table?
The size of the global Internet routing table is reaching 768k routes so the possibility of the TCAM resource exhaustion at 768k routes is coming.
What is routing in VLSI?
Answer Wiki. Routing in VLSI is to locate a set of wires in the routing space that connect all the nets in the net list .One must consider width of wires, wire crossings and capacities of channels etc.
What are virtual routes and global routes?
So, the early prediction of the route length is done based on the fan-out of the driving cell. These routes are known as the Virtual Routes. Global Routes: Once we place the standard in the floorplan, we have the actual location data of the cells in the floorplan.
How does global routing work?
In global routing, the region to be routed are divided into sectors (tiles/rectangles) called global routing cells or gcells. Then it decides tile to tile path for the nets and simultaneously trying to optimize the length, without actually making any physical connection.
What are virtual routes in floor plans?
Virtual Routes: Initially before or at the stage of the floorplan we don’t have any information about the placement of the cells. at this time we just have the knowledge of netlist which gives us the fan-out information of the cell. So, the early prediction of the route length is done based on the fan-out of the driving cell.