tcp/quic lab finished

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+# Computer Network Experiment: TCP vs QUIC (Linux Guide)
+
+This guide adapts the Windows-based experiment manual for a Linux environment.
+
+## 1. Prerequisites
+
+Ensure you have the following installed:
+- `gcc` (Compiler)
+- `quiche` library (Headers and Shared Object installed)
+- `openssl` (For certificates)
+- `tcpdump` or `wireshark` (For packet capture)
+- `iproute2` (For `tc` traffic control)
+
+## 2. Compilation
+
+Compile all programs using the provided Makefile:
+
+```bash
+make
+```
+
+This will generate:
+- `tcp_server`, `tcp_client` (Task 1)
+- `quic_server`, `quic_client` (Task 2)
+- `tcp_perf_server`, `tcp_perf_client` (Task 3 Performance)
+- `quic_perf_server`, `quic_perf_client` (Task 3 Performance)
+
+*Note: If `quiche` is not in the standard system path, edit the `Makefile` to point to the include/lib directories.*
+
+## 3. Task 1: Basic TCP Client-Server
+
+1. **Start the Server:**
+   ```bash
+   ./tcp_server
+   ```
+2. **Run the Client (in a new terminal):**
+   ```bash
+   ./tcp_client
+   ```
+   
+   **Expected Output:** The client sends "Hello...", server receives it and replies.
+
+## 4. Task 2: Basic QUIC Client-Server
+
+1. **Start the Server:**
+   ```bash
+   ./quic_server
+   ```
+2. **Run the Client (in a new terminal):**
+   ```bash
+   ./quic_client
+   ```
+
+   **Expected Output:** QUIC handshake completes, client sends data on a stream, server echoes it back.
+
+## 5. Task 3: Performance Analysis
+
+### 3.1 Connection Establishment Time
+
+1. Start capture on loopback:
+   ```bash
+   sudo tcpdump -i lo -w handshake.pcap
+   ```
+   *(Or use Wireshark on the `lo` interface)*
+
+2. Run the TCP or QUIC client/server pairs again.
+3. Open `handshake.pcap` in Wireshark to analyze the time difference between the first packet (SYN for TCP, Initial for QUIC) and the completion of the handshake.
+
+### 3.2 Throughput Test (100MB Transfer)
+
+**Baseline (Normal Network):**
+
+1. Run TCP Perf Server: `./tcp_perf_server`
+2. Run TCP Perf Client: `./tcp_perf_client`
+3. Record the MB/s output.
+4. Repeat for QUIC (`./quic_perf_server`, `./quic_perf_client`).
+
+**Simulating Network Conditions (Packet Loss / Delay):**
+
+We use Linux `tc` (Traffic Control) with `netem` instead of `clumsy`.
+
+**Scenario A: 5% Packet Loss**
+
+1. Apply 5% loss to the loopback interface:
+   ```bash
+   sudo tc qdisc add dev lo root netem loss 5%
+   ```
+2. Run the perf tests again.
+3. **Important:** Remove the rule after testing!
+   ```bash
+   sudo tc qdisc del dev lo root
+   ```
+
+**Scenario B: 100ms Delay**
+
+1. Apply 100ms delay:
+   ```bash
+   sudo tc qdisc add dev lo root netem delay 100ms
+   ```
+2. Run the perf tests again.
+3. Remove the rule:
+   ```bash
+   sudo tc qdisc del dev lo root
+   ```
+
+### 3.3 & 3.4 Advanced Tests
+
+- **Multiplexing:** The current `quic_perf_client` uses a single stream (Stream ID 4). You can modify the code to launch multiple streams in parallel to test head-of-line blocking resilience.
+- **Network Recovery:** Use `tc` to drop 100% packets (`loss 100%`) for 30 seconds during a long transfer, then remove the rule (`del`) to see if the connection recovers.