Path-Based Routing

Given a packet with a destination address of 1011, the third switching module in the top row uses the most significant bit, a 1, to direct the packet to the right output port which is connected to the seventh module on the second row. This modules uses the second most significant bit, a 0, to direct the packet out the left port which is connected to the fifth module in the third row. This module uses the third most significant bit, a 1, to direct the packet out of the right port which is connected to the sixth module in the bottom row. This modules uses the least significant bit, a 1, to direct the packet out of the right port.

The advantages of a path-based routing is that the hardware is simple and that the routing decision can be made with only the destination address.

The disadvantages of path-based routing is that it only works for certain topologies and that it is sensitive to any fault induced changes to these topologies.