Bandwidth Delay Product Calculator
计算BDP以用于TCP缓冲优化,并获取推荐的窗口大小和sysctl设置。
关于此工具
带宽时延积（BDP）是链路带宽与往返时间的乘积，它准确地告诉你在任一时刻线路上可以承载多少在途数据。这个数值决定了在长肥网络上实现满吞吐所需的理想 TCP 窗口，因为在这类高速度与高时延并存的网络中，过小的窗口会悄悄地限制你的传输速度。
使用时，输入链路带宽和往返时延，然后读取得出的 BDP 和建议的 TCP 窗口大小。它专为网络工程师、调优吞吐量的系统管理员，以及任何排查高时延链路上传输缓慢问题的人而设计。
提示：如果 TCP 窗口小于 BDP，链路就会闲置等待 ACK，吞吐量随之下降，因此请按此调整缓冲区大小。所有计算都在你的浏览器本地完成。
常见问题
代码实现
def bandwidth_delay_product(bandwidth_mbps: float, rtt_ms: float) -> dict:
"""
Calculate Bandwidth-Delay Product (BDP).
BDP = Bandwidth × RTT
This represents the amount of data in transit (in flight) at any time.
"""
bandwidth_bps = bandwidth_mbps * 1_000_000
rtt_sec = rtt_ms / 1000
bdp_bits = bandwidth_bps * rtt_sec
bdp_bytes = bdp_bits / 8
bdp_kb = bdp_bytes / 1024
bdp_mb = bdp_kb / 1024
# Recommended TCP window size (2x BDP for headroom)
tcp_window_bytes = int(bdp_bytes * 2)
return {
"bdp_bits": int(bdp_bits),
"bdp_bytes": int(bdp_bytes),
"bdp_kb": round(bdp_kb, 2),
"bdp_mb": round(bdp_mb, 4),
"tcp_window_recommended_bytes": tcp_window_bytes,
"tcp_window_recommended_kb": round(tcp_window_bytes / 1024, 1),
}
# Examples
scenarios = [
("Home broadband", 100, 20),
("Transatlantic fiber", 1000, 70),
("Satellite internet", 50, 600),
("Data center", 10_000, 1),
]
for name, bw, rtt in scenarios:
r = bandwidth_delay_product(bw, rtt)
print(f"{name} ({bw} Mbps, {rtt}ms RTT):")
print(f" BDP: {r['bdp_kb']:.1f} KB ({r['bdp_mb']:.2f} MB)")
print(f" Recommended TCP window: {r['tcp_window_recommended_kb']:.0f} KB")Comments & Feedback
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