Tag Archives: troubleshooting

Decoding Mist AP to Mist Edge tunnels with Wireshark

I don’t have any hard statistics to back this up, but I’m willing to fake bet that at least 90% of Mist’s customer deployments use local breakout (LBO) or local bridging as the method of offloading Wi-Fi client traffic onto the wired network. If this is your first time seeing the term LBO, it’s essentially bridging traffic directly onto the switch port that the AP is connected to. It requires a L2 network where your client VLANs are available on the switch(es) that your AP(s) are connected to.

Fig. 1 Local bridging or LBO deployment model courtesy of Mist’s website
Continue reading

Why speed tests aren’t always the answer when troubleshooting Wi-Fi networks

Table of Contents


    In my current role, we sometimes receive complaints about the Wi-Fi being slow or not working properly. When we ask what the issue is, we’re often sent responses referring to speed test results only that are supposed to serve as the definitive proof that something’s wrong with the Wi-Fi. What our user base often doesn’t understand is that there are many variables when it comes to speed tests in general, but when running these speed tests while connected to Wi-Fi, even more variables exist. Let me try to explain.

    Whether it be wired or Wi-Fi, there are theoretical and real-world throughput maximums in networking that are affected by a number of things. For example, even when you have a 1 Gbps wired connection, chances are you’ll never get full 1 Gbps line-rate speeds in a raw throughput test due to at minimum, the overhead needed to put bits onto the wire, not to mention whether the latency and TCP Window Size (if using TCP) can support the line-rate speed. Latency and the TCP Window Size are two things I’ll come back to in more detail later.

    Continue reading

    When is a client problem also an AP problem?

    My employer is currently building a new home office (HO) campus. In every building except two infrastructure support buildings, we are installing Mist AP45s which are 6E capable. The two support buildings received AP43s which don’t support 6E, but are Wi-Fi 6 (802.11ax) capable and still very capable APs.

    Why is that important? Well, as most if not all of you out there know by now, WPA3 is mandatory in 6 GHz. We haven’t deployed the AP45s in many places yet, so the new HO campus is an opportunity to really get our hands dirty with not just 6 GHz, but also WPA3-Enterprise on our corp WLAN and OWE on our guest WLAN to see how some of our client base would respond and operate. But Keith, didn’t you just say the support buildings had AP43s which don’t support 6 GHz operation? I did, but as I mentioned in the opening paragraph, they are 802.11ax capable and 802.11ax does support WPA3 which isn’t something we had broadly enabled yet in our environments up to this point!

    Continue reading

    My adventures with 6 GHz and my Pixel 6a phone

    I’ve always been someone who has advocated for buying your own tools to test and troubleshoot things. This applied when I was working primarily as a network engineer focused on route/switch, datacenter, and security technologies and it still applies today, now that I’m primarily focused on wireless. In my experience, some companies and/or management are better than others with regards to buying tools for their employees so you cannot always rely on them for help. Investing in yourself and your learning is critical in my opinion so don’t let that deter you. It’s also nice to be able to take those tools with you if you decide to move on to “greener pastures” one day. Unfortunately, not all tools are what I consider to be affordable for the average person, especially if they are somewhat frugal like myself. Just do the best you can, when you can.

    Continue reading

    Correlation != Causation

    This morning, I tweeted the message below without much context:

    With the 280 character limit of Twitter (hard to believe it used to be 140), sometimes it’s difficult to fully express an idea or the context behind it and instead of trying to create a messy, multi-threaded tweet, I just left it there as food for thought. But here on my blog, I can elaborate further on why this situation stood out to me and how it applies to you, the reader, who’s most likely in an IT related role.

    Continue reading