stop-and-wait-ARQ.zip_ARQ

/* Protocol 2 (stop-and-wait) also provides for a one-directional flow of data from sender to receiver. The communication channel is once again assumed to be error free, as in protocol 1. However, this time, the receiver has only a finite buffer capacity and a finite procesing speed, so the protocol must explicitly prevent the sender from flooding the receiver with data faster than it can be handled. */ typedef enum {frame_arrival} event_type; #include "protocol.h" void sender2(void) { frame s; /* buffer for an outbound frame */ packet buffer; /* buffer for an outbound packet */ event_type event; /* frame_arrival is the only possibility */ while (true) { from_network_layer(&buffer); /* go get something to send */ s.info = buffer; /* copy it into s for transmission */ to_physical_layer(&s); /* bye bye little frame */ wait_for_event(&event); /* do not proceed until given the go ahead */ } } void receiver2(void) { frame r, s; /* buffers for frames */ event_type event; /* frame_arrival is the only possibility */ while (true) { wait_for_event(&event); /* only possibility is frame_arrival */ from_physical_layer(&r); /* go get the inbound frame */ to_network_layer(&r.info); /* pass the data to the network layer */ to_physical_layer(&s); /* send a dummy frame to awaken sender */ } }