AirPort Express slow download speeds (good upload)

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Level 1

12 points

AirPort Express slow download speeds (good upload)

Hi all!

So, here's my issue: My AirPort Express worked great until yesterday allowing speeds of up to 100 Mbps for download. Yesterday something happened and download speed went way down, to 10-20 Mbps but upload is still 60-80 Mbps across multiple devices. When I connect PC with cable to the same Express, it gives 80/80 Mbps.

I tried everything I could think of (resetting router, with settings) – nothing helps. There was no changes in network configuration, devices or ISP.

Can anyone help? 😐

null-OTHER, AirPort Express

Posted on Mar 30, 2017 10:31 AM

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Answer 1

Top-ranking reply

nedis94 Author

Level 1

12 points

Mar 31, 2017 5:40 AM in response to nedis94

I have fixed it!

Curiously enough, I needed Windows version of AirPort utility for this 😐

What I think helped is to uncheck "Use wide channels" option. This changed 5GHz network from 40MHz to 20MHz and speeds went up to usual 80/80Mbps. Package loss also is under control now at 0.03%.

I changed a bunch of IPv6 settings on the last try as well, so I share them in attachments as well as I'm not sure maybe it was what helped (I'm too happy to have good connection to experiment further 😀)

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Answer 2

nedis94 Author

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12 points

Mar 30, 2017 11:38 AM in response to Bob Timmons

Yeah, setting it up as new was one of the things I tried.

I can't change my DNS unfortunately because I'm in dorm intranet network and they block all DNS except their own (so you don't use torrent sites).

I did test both 5Ghz and 2.4 Ghz – overall picture is the same with upload being 2X faster than download, and 2.4 network being slightly slower than 5.

I don't think it's other router interference, see the screenshot. It seems more like Express' processor (or whatever) doesn't keep up.

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Answer 3

nedis94 Author

Level 1

12 points

Mar 30, 2017 11:53 AM in response to Tesserax

1) Probably the software fault. Here's macOS screenshot

2) You're right about that, of course.

3) Not the case, because over the wire plugged to this very Express I get 80 Mbps download and upload

And here's Detailed view:

Your system: -

Plugin version: - ➖

TCP receive window: 131072 current, 131744 maximum

0.25 % of packets lost during test

Round trip time: 12 msec (minimum), 260 msec (maximum), 16 msec (average)

Jitter: -

0.00 seconds spend waiting following a timeout

TCP time-out counter: 216

583 selective acknowledgement packets received

No duplex mismatch condition was detected.The test did not detect a cable fault.No network congestion was detected.

0.9681 % of the time was not spent in a receiver limited or sender limited state.

0.0000 % of the time the connection is limited by the client machine's receive buffer.

Optimal receive buffer: - bytes

Bottleneck link: -

1802 duplicate ACKs set

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Answer 4

Tesserax

Level 10

151,689 points

Mar 30, 2017 11:45 AM in response to nedis94

I can't change my DNS unfortunately because I'm in dorm intranet network and they block all DNS except their own (so you don't use torrent sites).

At least three things stand out here:

It would be impossible to have no measured signal noise (0 dBm) value.
There are numerous other Wi-Fi operating nearby that can and should be introducing signal noise.
Your university, company, etc. is throttling the download bandwidth at your dorm location.

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Answer 5

Tesserax

Level 10

151,689 points

Mar 31, 2017 1:03 AM in response to nedis94

The results from the AirPort menu show just about as good as you can expect for the wireless connection between your Mac and the Express.

SNR = RSSI - Noise = -50 - (-96) = 46 dB, an excellent signal quality value.
MCS Index = 14. The highest value possible for the Express would be 15. At 14, the Tx rate (Data Rate) matches the index perfectly for a 5 GHz, 40 MHz-wide channel.

For the NDT results:

Packet loss @ 0.25% is high. It should be around 0.01-0.05%
RTT values look good.
The number of duplicate ACKs is also a bit high. Although this would be common with high packet loss. This would also trigger a greater amount of data packet retransmissions between your Mac and the Express.

What I can't tell is why you are experiencing the packet loss.

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Answer 6

Mar 30, 2017 10:57 AM in response to nedis94

When I connect PC with cable to the same Express, it gives 80/80 Mbps.

So, when you say that things were fine until yesterday......you really mean to say that wireless download speeds were OK until yesterday, correct?

Other than connecting the PC directly to the AirPort Express, what other troubleshooting steps have you performed?

What other devices have you used to check the connection speeds on your network?

There was no changes in network configuration, devices or ISP.

Just about every ISP is in the active process of switching their systems over from IPv4 to IPv6 communications.......(although your ISP will likely not tell you this unless you ask them)......so some interruptions and connection speeds are going to be intermittently affected during this ongoing process. The AirPort Express has very limited IPv6 capabilities as well, so that might be affecting things.

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Answer 7

nedis94 Author

Level 1

12 points

Mar 30, 2017 11:12 AM in response to Bob Timmons

Hey Bob, thanks for a quick reply!

Yes, I meant until yesterday my wireless download speeds were in the range of 60-80 Mbps. I don't even have a device with Ethernet port and borrowed neighbor's laptop to check wired connection speeds. My MacBook, Win 10 laptop and iPhone/iPad. Speeds wary not by much but upload is always WAY faster than download.

As for troubleshooting steps, I changed around channels, country codes, IPv6 modes (Link-local only, Automatically w/o "enable IPv6 connection sharing" and with it – doesn't seem to make any difference), tried different cable, radio modes, etc.

But signal level is -48 dBm with -96 dBm noise, connection link speed shown is 300Mbps and speeds went up a little bit recently but still are 30 Mbps for download and 70 Mbps for upload. I don't understand why on symmetric internet package upload speed is more than 2 times higher.

I will clarify with ISP about IPv6. Are new AirPort Extremes any better with this or should I look elsewhere if I decide to upgrade my router?

Meantime, if you have any other suggestions, I'd be glad to hear them.

I even found this article from 2012, but could not find way to disable WMM even manually editing Express' config file

http://www.ybrikman.com/writing/2012/02/19/got-slow-download-but-fast-upload/

Thanks!

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Answer 8

Mar 30, 2017 11:24 AM in response to nedis94

At this point, about the only thing that you can do is reset the AirPort Express back to factory default settings and then set it up again.

You can try changing the DNS settings.....as suggested by another user......but this would not usually have anything to do with download/upload speeds.

How many other wireless networks can you "see" at your location? Are there any other networks that are using the same channel(s) that you are using?

Are you checking speeds using a 2.4 GHz connection, or a 5 GHz connection?

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Answer 9

Tesserax

Level 10

151,689 points

Mar 30, 2017 11:35 AM in response to nedis94

The article you reference is to adjust the Quality of Service (QOS) feature of a Linksys router. Unfortunately, the AirPort base stations, like those of some other manufacturers, does not have this feature and there is not adjustments for it.

Try running the following MLab performance test: NDT (Network Diagnostic Test) and post the Details results section.

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Answer 10

nedis94 Author

Level 1

12 points

Mar 30, 2017 11:41 AM in response to Tesserax

Aha, I see.

Here's what I got from NDT:

{ "c2sRate": 61679, "s2cRate": 11428.707626713387, "CurMSS": "1448", "X_Rcvbuf": "87380", "X_Sndbuf": "100464", "AckPktsIn": "6975", "AckPktsOut": "0", "BytesRetrans": "90912", "CongAvoid": "5046", "CongestionOverCount": "0", "CongestionSignals": "26", "CountRTT": "5174", "CurCwnd": "21720", "CurRTO": "216", "CurRwinRcvd": "131072", "CurRwinSent": "7040", "CurSsthresh": "18824", "DSACKDups": "0", "DataBytesIn": "602", "DataBytesOut": "15176110", "DataPktsIn": "1", "DataPktsOut": "10259", "DupAcksIn": "1802", "ECNEnabled": "0", "FastRetran": "26", "MaxCwnd": "39096", "MaxMSS": "1448", "MaxRTO": "680", "MaxRTT": "260", "MaxRwinRcvd": "131744", "MaxRwinSent": "7040", "MaxSsthresh": "18824", "MinMSS": "1448", "MinRTO": "213", "MinRTT": "12", "MinRwinRcvd": "84736", "MinRwinSent": "5792", "NagleEnabled": "1", "OtherReductions": "2", "PktsIn": "6976", "PktsOut": "10259", "PktsRetrans": "63", "RcvWinScale": "7", "SACKEnabled": "3", "SACKsRcvd": "583", "SendStall": "0", "SlowStart": "70", "SampleRTT": "13", "SmoothedRTT": "13", "SndWinScale": "5", "SndLimTimeRwin": "0", "SndLimTimeCwnd": "10013981", "SndLimTimeSender": "330482", "SndLimTransRwin": "0", "SndLimTransCwnd": "18", "SndLimTransSender": "18", "SndLimBytesRwin": "0", "SndLimBytesCwnd": "15055728", "SndLimBytesSender": "120382", "SubsequentTimeouts": "0", "SumRTT": "84066", "Timeouts": "0", "TimestampsEnabled": "1", "WinScaleRcvd": "5", "WinScaleSent": "7", "DupAcksOut": "0", "StartTimeUsec": "332443", "Duration": "10345523", "c2sData": "5", "c2sAck": "5", "s2cData": "8", "s2cAck": "10", "half_duplex": "0", "link": "100", "congestion": "1", "bad_cable": "0", "mismatch": "0", "spd": "11.74", "bw": "13.51", "loss": "0.002534360", "avgrtt": "16.25", "waitsec": "0.00", "timesec": "10.00", "order": "0.2584", "rwintime": "0.0000", "sendtime": "0.0319", "cwndtime": "0.9681", "rwin": "1.0051", "swin": "0.7665", "cwin": "0.2983", "rttsec": "0.016248", "Sndbuf": "100464", "aspd": "0.00000", "CWND-Limited": "0.00", "minCWNDpeak": "7240", "maxCWNDpeak": "39096", "CWNDpeaks": "26", "ServerToClientSpeed": 11.428707626713386, "ClientToServerSpeed": 61.679, "Jitter": 248 } === Results sent by the server ===

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Answer 11

Mar 30, 2017 11:47 AM in response to nedis94

Other than trying another AirPort Express, or another router, not much that you can do.....since the Express has very limited adjustment settings.

If the product is less than a year old, ask Apple for a replacement.

We don't know how old the Express might be, but 3-4 years.....on average.....is about it for the Express before the performance of the wireless radio starts to decline.

Here, we are assuming that other users are getting full speeds on their networks with their routers.

Unfortunately, the dorm is not a very friendly place for wireless routers, which is why most schools will not allow them.

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Answer 12

nedis94 Author

Level 1

12 points

Apr 1, 2017 1:51 AM in response to nedis94

An update:

It actually had nothing to do with wide channel!

After playing around a little bit more, I discovered that the cause was IPv6 settings. I can only hit full download speed if it's in Automatic Tunnel mode. Any other mode results in bottleneck at 20Mbps.

But with Tunnel mode enabled, my internet connection drops about every hour for 20-30 seconds... What can be the cause?

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