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My internet download speed from my D-Link wifi router is 24 M bits/s

From ethernet the download speed is 50 Mbits/s

I am using Tp-link AC600 Archer T2U Plus wifi adapter with Rapberry pi 3B+

I tried to use it with 5 Ghz and 2.4 Ghz both. The speed for the adapter is supposed to be 200 Mbps 2.4 Ghz / 433 Mbps on 5 Ghz.

But even with the 5Ghz I can get only 19 Mbps download speed when connected to the hotspot. It shows a network speed of 54 Mbps in my wifi settings whereas the D-link router shows 72 Mbps on the 2.4 Ghz.

Here is my hostapd.conf:

interface=wlan1
driver=nl80211
hw_mode=a
channel=48
ieee80211n=1
ieee80211ac=1
wmm_enabled=0
macaddr_acl=0
ignore_broadcast_ssid=0
auth_algs=1
wpa=2
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP

ssid=Wlan1

wpa_passphrase=1234567a

What am I doing wrong here?

  • Where's the hotspot, is it on that D-Link router? – Dmitry Grigoryev Nov 18 at 13:20
  • No. On the raspberry pi. D link router has its own WiFi access point – Arahasya Nov 18 at 19:34
  • Then, how is the RPi connected to the Internet and how fast is that connection? I suggest you add such details to your question, perhaps draw a diagram showing network links, otherwise you may not get a useful answer despite the bounty. – Dmitry Grigoryev Nov 19 at 8:06
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+50

Check out this test of RPi performance w.r.t various network interfaces. Built-in WiFi on an RPi 3 is capped at 36 Mbps, and a USB dongle is capped at about 80Mbps in ideal conditions. At 10 meters distance, those numbers drop to 32 and 64 Mbps respectively.

After you factor in overhead from two interfaces running simultaneously, routing performance losses, delays, etc., 19 Mb/s is actually a quite decent number.

If you need high performance, use a router. Those are optimized for maximum raw Mbps at the expense of other features, so a generic board like Raspberry running a generic Linux distro will never come close to that.

  • I am using a 5GHz external adapter. Any reason it should still have low speed? As the USB throughput is not the issue – Arahasya Nov 25 at 17:10
  • @Arahasya There is an unavoidable delay when a data packet is routed from one network interface to the other. Many routers have hardware-accelerated routing pipelines which work on several packets which can be "statelessly" routed in parallel. On the RPi the CPU is used to copy a data buffer from one RAM location to another, and AFAIK this is done on one packet at a time regardless of how complex the routing decision is. – Dmitry Grigoryev Nov 26 at 8:29
  • 5 M Bits or Bytes? – Arahasya Nov 26 at 8:56
  • @Arahasya Anecdotally, I've once made a router out of an Orange Pi Zero. I didn't spend time optimizing it, and the throughput from a straightforward implementation was only 5 Mb/s. For reference, OPi Zero's WiFi is capped at about 15 Mb/s. – Dmitry Grigoryev Nov 26 at 9:05
  • @Arahasya Megabits. There's no way to fix a comment so I removed it and posted a new one which is fixed. – Dmitry Grigoryev Nov 26 at 9:06

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