diff --git a/data/chapter1/preface.tex b/data/chapter1/preface.tex
index 79ce111..6f84f35 100644
--- a/data/chapter1/preface.tex
+++ b/data/chapter1/preface.tex
@@ -7,3 +7,4 @@
 掌握以太网、802.11、ARP、IP、ICMP和TCP等重要协议传输单元结构，
 深入理解相关网络命令和重要协议算法的工作原理，
 从而培养网络故障检测、网络性能改进和网络安全分析的能力。
+(备注：第二版将增补实验1.4: IEEE 802.11协议分析。)
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diff --git a/data/chapter1/section3.tex b/data/chapter1/section3.tex
index 0fc9696..6538304 100644
--- a/data/chapter1/section3.tex
+++ b/data/chapter1/section3.tex
@@ -467,3 +467,59 @@ CUBIC的关键特征是：cwnd窗口的增长依赖两次丢包的时间。
   \item (10分)完成任2道思考题。
   \item (10分)记录自己在本次实验中所遇到的问题，以及心得感悟实验总结。
 \end{enumerate}
+
+\subsection{附录}
+\label{subsec:c1_s3_additionalprg}
+1．	Python3 TCP socket通信程序。
+\ 服务端 server.py
+\lstset{language=python3}
+\begin{lstlisting}
+  import socket
+  import time
+  def recv_data(sock,length):
+      data=b''
+      while len(data) < length:
+          more = sock.recv(length - len(data))
+          if not more:
+              pass
+          data += more
+      return data         
+  s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+  # 设置接收缓冲区大小为1024
+  s.setsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF, 1024)
+  s.bind(('0.0.0.0', 9999))
+  s.listen(1)
+  print("Sever listening on 9999...")
+  try:
+      sc, addr = s.accept()
+      while True:
+          rcvdata = recv_data(sc,16)
+          time.sleep(0.01)
+          pass
+  finally:
+      sc.close()
+      s.close() 
+\end{lstlisting}
+\\
+\ 客户端
+\lstset{language=python3}
+\begin{lstlisting}
+  import socket
+  import time
+  ip_port = ("192.168.100.144", 9999)
+  data = "0123456789\n"*100
+  c = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+  try:
+      c.connect(ip_port)
+      print("Connected.")
+      time.sleep(1)  
+      i=0
+      while i<10:
+          print("Send:"+data)
+          c.send(data.encode())
+          i=i+1
+  finally:
+      print("Sent. Waiting....")
+  while True:
+      time.sleep(0.001)  
+\end{lstlisting}
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