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                          README                                   
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                         rUDP 1.0
                         17 Oct. 2014
                         author:Hugo Chan
                      
                  C++ Programs for Socket Programming 

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Contents:

1. Description
2. Implementation
3. Bugs
4. Notice

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1. Description:

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Reliable end-to-end in-order data delivery inside the application layer on top of the UDP.

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2. Implementation:

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-Finite State Machine design for implementation of interactions between the sender and receiver. -Buffer Design: ---rUDP_sender: typedef struct { char buf[MAXNUM]; int front, rear; }QueueBuf;

// Buffer Information Management 
// linked queue
typedef struct // element type
{
	int seqnum = 0;
	int length = 0;
}Info;

	typedef struct node
{ 
	Info info;
	node* next = NULL;
}InfoNodeType;

typedef struct
{
	InfoNodeType* front;
	InfoNodeType* rear;
}BufInfoManagLq;

---rUDP_receiver: typedef struct{ int seqnum; int payload_len; char seg[sizeof(Segment)]; }RecvNode;

typedef struct{
	int index = 0;
	RecvNode recv_array[10];
}RecvBuf;

-multiple threads for FSM and main function

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3. Bugs:

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the current version has something wrong with the test_sender.cpp file. Because sometimes it can only send part of the single line read from the input file. But the rUDP_sender class is fine, we can fix the issue in our application program in test_sender.cpp file.

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4. Notice:

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When receive buffer is full, it automatically adopts memory substitution(replace the last element with the new one). Also: no trunc, no fast retransmit, retransmit one each time, initial seqnum predefined, the sender leaves the acknum empty in its sent segment, the receiver leaves seqnum empty in its feedback segment, no size-limitation and reuse for the sequence number...