Thus , backpressure flow control and deflection routing are possible alternative solutions to the problem of congestion in the network. P. Palnati, M. Gerla, and E. Leonardi. Deadlockfree Routing in an Optical Interconnect for HighSpeed Wormhole Routing Networks . Technical Report CSD-950064, UCLA, 1995. Upon detection of a deadlock, one or more worms could be dropped to break the cycle.
Similar problems occur in packet networks with window based flow control.
In Myrinet, source routing is used. P. Palnati, M. Gerla, and E. Leonardi. These algorithms are difficult to design, and inevitably add latency to the connection establishment phase. Thus , this approach is considered impractical and is not pursued further. An alternative is to dedicate a pool of links from the network topology to support all QoS connections.