Access from '18.116.13.192'
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It is 10:12 JST now.
You are in US.
It is 10:12 JST now.
WiFi6 思ったほど速度は出ない・・・
WiFi6 有線LANより速度が早いはずなのに、何か変わらないような・・・
リテラシーの高いユーザーやゲームユーザーなら、こんな経験ありますよね！？
さて実態は？
図のようにPCからAPへの通信は数字の順に通信され、それぞれの通信が1回づつ別途プロトコル(つなぐよ〜 うんイイよ〜 って感じの手順）を毎回やっています。
それに比べ有線の場合は送信・受信は常に並行して行われます(全2重)。また通信単位のプロトコルもありません。スイッチングハブが通信上で「どこからどこへ繋ぐ」ということで行われているので衝突検知もたいした事がないので結果 、WiFi6より1Gbps 有線LANの方が早くなります。
以下の例は 同じAPのWiFi6に繋がった機器間の pingと速度計測(ipferf3) の結果です。
同一セグメント NIC WiFi6 間
WiFi6 NIC
PING 192.168.16.14 (192.168.16.14): 56 data bytes 64 bytes from 192.168.16.14: icmp_seq=0 ttl=64 time=11.946 ms 64 bytes from 192.168.16.14: icmp_seq=1 ttl=64 time=9.180 ms 64 bytes from 192.168.16.14: icmp_seq=2 ttl=64 time=10.803 ms 64 bytes from 192.168.16.14: icmp_seq=3 ttl=64 time=9.662 ms 64 bytes from 192.168.16.14: icmp_seq=4 ttl=64 time=3.720 ms 64 bytes from 192.168.16.14: icmp_seq=5 ttl=64 time=8.306 ms 64 bytes from 192.168.16.14: icmp_seq=6 ttl=64 time=12.222 ms 64 bytes from 192.168.16.14: icmp_seq=7 ttl=64 time=8.885 ms 64 bytes from 192.168.16.14: icmp_seq=8 ttl=64 time=4.237 ms 64 bytes from 192.168.16.14: icmp_seq=9 ttl=64 time=4.406 ms --- 192.168.16.14 ping statistics --- 10 packets transmitted, 10 packets received, 0.0% packet loss round-trip min/avg/max/stddev = 3.720/8.337/12.222/3.009 m
Connecting to host 192.168.16.14, port 5201 [ 5] local 192.168.16.25 port 52366 connected to 192.168.16.14 port 5201 [ ID] Interval Transfer Bitrate [ 5] 0.00-1.01 sec 91.8 MBytes 766 Mbits/sec [ 5] 1.01-2.00 sec 88.2 MBytes 742 Mbits/sec [ 5] 2.00-3.00 sec 86.6 MBytes 726 Mbits/sec [ 5] 3.00-4.00 sec 75.9 MBytes 637 Mbits/sec [ 5] 4.00-5.01 sec 78.1 MBytes 654 Mbits/sec [ 5] 5.01-6.00 sec 81.1 MBytes 684 Mbits/sec [ 5] 6.00-7.00 sec 68.1 MBytes 570 Mbits/sec [ 5] 7.00-8.00 sec 81.1 MBytes 681 Mbits/sec [ 5] 8.00-9.00 sec 77.9 MBytes 653 Mbits/sec [ 5] 9.00-10.00 sec 78.8 MBytes 661 Mbits/sec - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bitrate [ 5] 0.00-10.00 sec 808 MBytes 677 Mbits/sec sender [ 5] 0.00-10.02 sec 805 MBytes 674 Mbits/sec receiver r
これでは有線で外部との通信とあまり変わらないどころか外部のサイトによっては遅い(DS-Lite速度計測)ですね。WiFi ってすごいオーバーヘッドがかかるのです。通信パケットが早くても一方通行な上でオーバーヘッドが大きいのです。下図は有線LANでの結果で、当然、両面通行（全二重）で通信ができます。いくら頑張ってもギガビット有線の方が早くなるのは当然ですね。ましてや2.5Gbpsでは！
2.5G NIC 同士の iperf3 結果
PING 192.168.8.19 (192.168.8.19) 56(84) bytes of data. 64 bytes from 192.168.8.19: icmp_seq=1 ttl=64 time=0.240 ms 64 bytes from 192.168.8.19: icmp_seq=2 ttl=64 time=0.195 ms 64 bytes from 192.168.8.19: icmp_seq=3 ttl=64 time=0.148 ms 64 bytes from 192.168.8.19: icmp_seq=4 ttl=64 time=0.147 ms 64 bytes from 192.168.8.19: icmp_seq=5 ttl=64 time=0.138 ms 64 bytes from 192.168.8.19: icmp_seq=6 ttl=64 time=0.178 ms 64 bytes from 192.168.8.19: icmp_seq=7 ttl=64 time=0.146 ms 64 bytes from 192.168.8.19: icmp_seq=8 ttl=64 time=0.135 ms 64 bytes from 192.168.8.19: icmp_seq=9 ttl=64 time=0.148 ms 64 bytes from 192.168.8.19: icmp_seq=10 ttl=64 time=0.178 ms --- 192.168.8.19 ping statistics --- 10 packets transmitted, 10 received, 0% packet loss, time 9219ms rtt min/avg/max/mdev = 0.135/0.165/0.240/0.031 mss
Connecting to host 192.168.8.19, port 5201 [ 5] local 192.168.8.14 port 56546 connected to 192.168.8.19 port 5201 [ ID] Interval Transfer Bitrate Retr Cwnd [ 5] 0.00-1.00 sec 284 MBytes 2.38 Gbits/sec 0 571 KBytes [ 5] 1.00-2.00 sec 281 MBytes 2.36 Gbits/sec 0 600 KBytes [ 5] 2.00-3.00 sec 280 MBytes 2.35 Gbits/sec 0 600 KBytes [ 5] 3.00-4.00 sec 280 MBytes 2.35 Gbits/sec 0 660 KBytes [ 5] 4.00-5.00 sec 281 MBytes 2.36 Gbits/sec 0 660 KBytes [ 5] 5.00-6.00 sec 280 MBytes 2.35 Gbits/sec 0 660 KBytes [ 5] 6.00-7.00 sec 281 MBytes 2.36 Gbits/sec 0 660 KBytes [ 5] 7.00-8.00 sec 280 MBytes 2.35 Gbits/sec 0 660 KBytes [ 5] 8.00-9.00 sec 281 MBytes 2.36 Gbits/sec 0 660 KBytes [ 5] 9.00-10.00 sec 280 MBytes 2.35 Gbits/sec 0 660 KBytes - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.00 sec 2.74 GBytes 2.36 Gbits/sec 0 sender [ 5] 0.00-10.04 sec 2.74 GBytes 2.34 Gbits/sec receiver