This project is an Enhanced UDP implementation designed to provide reliable data transmission over an inherently unreliable UDP protocol. It introduces key mechanisms such as:
- Packet acknowledgment (ACK)
- Retransmissions upon timeout
- Sequence numbering
These features ensure data integrity and order, making UDP a more robust transport mechanism.
- Reliable Data Transfer: Implements sequence numbers and ACKs to prevent data loss.
- Timeouts & Retransmissions: Automatically detects lost packets and retransmits them.
- Packet Sequence Numbering: Ensures packets arrive in the correct order.
- Bandwidth Utilization Metrics: Calculates throughput and network efficiency.
- Customizable Buffer Size: Allows adjustment of packet size for optimized performance.
- Language: C
- Networking: UDP Sockets
- Testing Platform: CloudLab
- OS Compatibility: Linux (tested on Ubuntu)
- Build System:
Makefile - Performance Metrics: Bandwidth, Throughput Analysis
Clone the repository
git clone https://github.com/maddypaulson/enhanced-udp.git
Run the make file from the main project directory
make
Run the following command to start the receiver:
./receiver <UDP Port> <filename.txt>
Run the following command in a seperate terminal to start the sender:
./sender <receiver hostname> <receiver port> <transfer filename.txt> <num bytes to transfer>
- The buffer size controls the amount of data per packet.
- The packet header contains essential metadata for reliable transmission.
- Uses ACK timeouts (ACK_TIMEOUT_USEC) to detect lost packets.
- Limits retransmissions with MAX_RESEND_ATTEMPTS to prevent infinite loops.
- Measures throughput and bandwidth efficiency.
- Includes overhead and retransmissions in the calculation.
- Ensures packets are processed in order.
- Helps identify missing or out-of-order packets.
- Implements a reliability layer by resending packets if no acknowledgment is received.
- Uses a special packet to signal the end of transmission.
- Ensures the receiver knows when all data has been sent.
- Does not use Go-Back-N or Selective Repeat pipelining.
- Vulnerable to small packet loss, which impacts performance.
The throughput is calculated using the following formula:
where:
- totalBytesSent: The total number of bytes of the payload sent.
- sizeof(PacketHeader): The size of the header of each packet.
- sequenceNumber: The total number of packets sent.
- 8: Converts bytes to bits.
- duration: The total time taken for transmission in seconds.
The bandwidth is calculated using the following formula:
where:
- throughput is bits sent per second
- LINK_CAPACITY is the maximum amount of data that can be transmitted over a communication channel within a given time frame.
- 100 converts the value to a bandwidth percentage.
Requirement: the protocol must, in steady state (averaged over 10 seconds), utilize at least 70% of bandwidth when there is no competing traffic, and packets are not artificially dropped or reordered.
- The test was conducted using CloudLab to ensure isolated network conditions.
- The sender runs on Juno, while the receiver runs on Europa.
- A 20Mbit/s link capacity was enforced.
- The transmission duration was measured over 10 seconds.
- A 20.1 MB file (SampleVideo.mp4) was used for accurate results.
| Metric | Result |
|---|---|
| Achieved Bandwidth | 83.32% |
| Throughput | 17.47 Mb/s |
| Buffer Size | 10,000 bytes per packet |
| Link Capacity | 20 Mbit/s |
| Total Bytes Sent | 21,086,550 bytes |
| Total Bytes Received | 21,069,678 bytes |