滑窗协议代码
时间: 2023-07-23 20:04:19 浏览: 34
滑动窗口协议是一种数据传输协议,它允许发送方连续发送多个数据包,而不需要等待确认。以下是一个简单的Python实现:
```python
import socket
# 发送方IP地址和端口号
sender_ip = '127.0.0.1'
sender_port = 12345
# 接收方IP地址和端口号
receiver_ip = '127.0.0.1'
receiver_port = 12346
# 创建UDP socket
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
# 设置超时时间(单位:秒)
sock.settimeout(5)
# 滑动窗口大小
window_size = 4
# 待发送的数据包
data = ['packet1', 'packet2', 'packet3', 'packet4', 'packet5']
# 初始化窗口
send_base = 0
next_seq_num = 0
window = data[send_base:send_base + window_size]
while True:
# 发送窗口中未确认的数据包
for i in range(len(window)):
if send_base + i >= len(data):
break
if next_seq_num < send_base + window_size:
sock.sendto(window[i].encode(), (receiver_ip, receiver_port))
print('发送数据包', i + send_base)
next_seq_num += 1
# 接收ACK
try:
ack, _ = sock.recvfrom(1024)
ack_num = int(ack.decode())
print('收到ACK', ack_num)
if ack_num >= send_base:
send_base = ack_num + 1
window = data[send_base:send_base + window_size]
if not window:
print('传输完成')
break
except socket.timeout:
print('超时,重发数据包', send_base)
next_seq_num = send_base
window = data[send_base:send_base + window_size]
```
代码中,`sender_ip`和`sender_port`是发送方的IP地址和端口号,`receiver_ip`和`receiver_port`是接收方的IP地址和端口号。`window_size`是滑动窗口的大小,`data`是待发送的数据包列表。`send_base`是已发送并收到ACK的数据包序号,`next_seq_num`是下一个待发送的数据包序号,`window`是窗口中未确认的数据包列表。
程序在进入循环后,首先发送窗口中未确认的数据包。如果收到ACK,则将`send_base`更新为ACK的序号加1,并将窗口更新为从`send_base`开始的`window_size`个数据包。如果窗口为空,则传输完成,退出循环。如果超时,则重发从`send_base`开始的所有数据包,将`next_seq_num`设为`send_base`,并将窗口更新为从`send_base`开始的`window_size`个数据包。