WiFi Connection Errors on C743 and Spin 11 (Association Errors)

czsmith
czsmith Member Posts: 2 New User
edited November 2023 in 2019 Archives
I am not sure how to report a bug or if this is the proper place to post a technical request.  If not, can someone please let me how to submit the proper type of bug report?


My Acer C732 (P/N C732-C6WU) is unable to connect with the GL-iNet MT300N-v2 mini router.  I've also tested this on an Acer Spin 11 and it has the exact same problem.  I'm currently running version 76.0.3809.102 on the Beta channel.  The problem, however has existed on the regular channel and on previous regular and beta versions over the past eight months.

This router is one of the more popular travel routers and is an Amazon Choice.  

I have been working with the router's manufacturer, GL-iNet.  The problem appears only on this AP; the Chromebooks can connect just fine with other vendors' routers.

The problem shows as an "Unknown Error" on the Chromebook.  I have captured traces of the WiFi connection process and find the following.
  1. The Chromebook properly authenticates.
  2. The Chromebook sends an Association Request. 
  3. The AP responds with an Association Response which the Chromebook Acknowledges.  At this point, we' can be pretty certain the that Chomebook has seen the AP's response.
  4. The Chromebook continues to send Association Requests.  These are all flagged with a Retransmit indicator and have the same serial number.
  5. All of these requests get a new Association Response from the AP.  (The responses have increasing SN's.)
  6. For some reason, the AP does not start the 4-way handshake.
  7. Eventually, the Chromebook stops sending Association Requests.
  8. After about six seconds, the AP deauthenticates from the Chromebook and the Chromebook either displays the error message, or moves on to try connecting to another SSID.  The Deauthentication packet reports an error of 15 - 4-way handshake timeout.

This happens nearly all the time.  From time to time, however, the AP does start the 4-way handshake and the connection succeeds. There are still an excessive number of Association Request retransmissions.

There is nothing obvious in the timing.  The Chromebook resends Association Requests anywhere from 1 to 15 msec after the previous one.  Transmission does not depend on receiving a response or not.  All responses, however, are acknowledged quickly.

I have monitored the process on an Acer Chromebook R13 as well, and that Chromebook connects without problem.  In this case, the Chromebook sends only two Association Requests, one of which is acknowledged.  After that acknowledgement, the AP starts the 4-way handshake and the connection succeeds quickly.  The Association Request has quite a few differences on the R13 than the C732/Spin 11.

Attached are some pcap traces, as well as a spreadsheet with a simplified view.  Rows in green are Association Requests (whether original or retransmission) and in blue are the Association Responses.  The "Req Pending" shows the count of pending responses.  Retransmitted responses are ignored in computing this.  We can see that every request is ultimately paired with a response and that there are never more non-retransmitted responses than requests.

The sequence at the end (skipping over the Authentication and nearly dozen Association Request/Response packets) looks like:


The Action packets are all Radio Measurements.  The IntelCor is the Chromebook and the GuangLia is the router (AP) running as a repeater.

Now, the successful connection on the Chromebook R13 shows a different story:

The Chromebook R13 (Azurewav) does not spew Association Requests.  Of course, its Association Request does not have the same parameters as the failing Chromebooks do.

There are two problems going on here...
  1. Why are the Chromebooks constantly resending Association Requests?  The requests are clearly being responded to, and the Chromebooks acknowledge that.  Once the 4-way handshake starts, the Chromebooks stop sending Association Requests [as the should].
  2. What is causing the AP not to start the 4-way handshake after sending an Association Response?  There must be something in the packet environment that is causing the AP not to follow the normal protocol.  My guess s it's most likely something in the Association Request, the acknowledgement to the Association Response or the overall timing.

As this is the top choice and "Amazon Choice" for "mini router" at Amazon, and the number 5 entry under "travel router" (and the less expensive than all the entries above it), I would think this would be an important problem for Acer (or Google) to address.  Especially since Chromebooks are often purchased as a "travel laptop."

Answers

  • czsmith
    czsmith Member Posts: 2 New User
    OOPS...  I proofread the body of the posting, but not the title...

    It's a C732 not a C743.

    Sorry.