arqprotocol_rar stop-and-waitarq_c.txt

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stop-and-waitARQ.c

/* 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(&amt;buffer); /* go get something to send */ 
s.info = buffer; /* copy it into s for transmission */ 
to_physical_layer(&amt;s); /* bye bye little frame */ 
wait_for_event(&amt;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(&amt;event); /* only possibility is frame_arrival */ 
from_physical_layer(&amt;r); /* go get the inbound frame */ 
to_network_layer(&amt;r.info); /* pass the data to the network layer */ 
to_physical_layer(&amt;s); /* send a dummy frame to awaken sender */ 
} 
}