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客戶端和伺服器之間的 iperf 輸出差異

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客戶端和伺服器之間的 iperf 輸出差異

過去 4 小時一直在玩 iperf，我無法理解為什麼客戶端和伺服器的結果不同。

考慮客戶端上的以下 iperf 輸出：

iperf -c 91.121.112.163 -p 2222
------------------------------------------------------------
Client connecting to 91.121.112.163, TCP port 2222
TCP window size: 1.06 MByte (default)
------------------------------------------------------------
[  3] local 10.0.0.160 port 36726 connected with 91.121.112.163 port 2222
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-11.4 sec  1.88 MBytes  1.38 Mbits/sec

這是伺服器上相應的輸出：

iperf -V -s -p 2222
------------------------------------------------------------
Server listening on TCP port 2222
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[  4] local ::ffff:91.121.112.163 port 2222 connected with ::ffff:86.209.154.156 port 36726
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-19.1 sec  1.88 MBytes   823 Kbits/sec

那麼，客戶端以 1.38Mbits/sec 上傳，但伺服器以 823kbits/sec 接收？

有人對這些令人困惑的結果有解釋嗎？

答案1

我認為問題在於客戶端正在與緩衝出站流量的設備進行通信，因此客戶端認為它是在伺服器實際收到最後一個資料區塊之前完成的。我在 iperf 中經常注意到這一點 - 伺服器的逐秒報告比客戶端的穩定得多。我還注意到第一的客戶端中的第二個始終是最高吞吐量，我認為它正在填充路徑上正在執行此操作的任何設備的緩衝區。以下是客戶端和伺服器測試雙向 7Mbps 的連結...

------------------------------------------------------------
Client connecting to 204.22.22.104, TCP port 5001
TCP window size: 20.0 KByte (default)
------------------------------------------------------------
[  3] local 10.125.20.100 port 49248 connected with 204.22.22.104 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0- 1.0 sec  1.12 MBytes  9.44 Mbits/sec
[  3]  1.0- 2.0 sec   768 KBytes  6.29 Mbits/sec
[  3]  2.0- 3.0 sec   768 KBytes  6.29 Mbits/sec
[  3]  3.0- 4.0 sec   896 KBytes  7.34 Mbits/sec
[  3]  4.0- 5.0 sec   768 KBytes  6.29 Mbits/sec
[  3]  5.0- 6.0 sec   896 KBytes  7.34 Mbits/sec
[  3]  6.0- 7.0 sec   768 KBytes  6.29 Mbits/sec
[  3]  7.0- 8.0 sec   896 KBytes  7.34 Mbits/sec
[  3]  8.0- 9.0 sec   768 KBytes  6.29 Mbits/sec
[  3]  9.0-10.0 sec   768 KBytes  6.29 Mbits/sec
[  3]  0.0-10.2 sec  8.38 MBytes  6.91 Mbits/sec
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[  4] local 204.22.22.104 port 5001 connected with 10.125.20.100 port 49248
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0- 1.0 sec   828 KBytes  6.78 Mbits/sec
[  4]  1.0- 2.0 sec   764 KBytes  6.25 Mbits/sec
[  4]  2.0- 3.0 sec   857 KBytes  7.02 Mbits/sec
[  4]  3.0- 4.0 sec   815 KBytes  6.68 Mbits/sec
[  4]  4.0- 5.0 sec   811 KBytes  6.64 Mbits/sec
[  4]  5.0- 6.0 sec   814 KBytes  6.66 Mbits/sec
[  4]  6.0- 7.0 sec   815 KBytes  6.68 Mbits/sec
[  4]  7.0- 8.0 sec   814 KBytes  6.66 Mbits/sec
[  4]  8.0- 9.0 sec   812 KBytes  6.65 Mbits/sec
[  4]  9.0-10.0 sec   806 KBytes  6.60 Mbits/sec
[  4]  0.0-10.6 sec  8.38 MBytes  6.64 Mbits/sec

答案2

來自客戶：（強調我的）

[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-**11.4** sec  1.88 MBytes  1.38 Mbits/sec

從伺服器：

[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-**19.1** sec  1.88 MBytes   823 Kbits/sec

由於某種原因，伺服器認為測試花費的時間比客戶端長約 8 秒。這足以將整體頻寬（從伺服器的角度）降至 823 Kbps。

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