The diagonal model for the channel routing problem consists of using diagonal tracks instead of the horizontal and vertical tracks used in the Manhattan model. Using this approach, a lower bound is given for the minimum channel width. This lower bound is equal to d, the density of the channel, which is defined as the maximum number of nets crossing a vertical line. This result is the same as for the classical Manhattan model. The authors present a routing algorithm for this diagonal model, which performs the routing with a channel width not exceeding 2 d + 3, instead of d + O ( &sqrt;m ) for the best algorithm using the Manhattan model, where m is the number of nets.

This algorithm may be better, but experimental results comparing the two models are lacking. Nevertheless, this paper is interesting, gives novel results, and is well written.