Sniff Wi-Fi

It's summer in Los Angeles, which can only mean one thing: Sequels! As movie fans indulge in a third 'Avengers', a fifth 'Jurassic Park', and what feels like a seven hundreth 'Star Wars', this here blog is providing a sequel to a probably-long-forgotten Sniff Wi-Fi post called ' Why Are You Slowing Down My Wi-Fi, Apple? ' Turn down the lights, pop some popcorn, and enjoy the twists and turns of this harrowing look into Wi-Fi Calling on iPhones. Several months ago, this blog highlighted the Wi-Fi behavior of the iPhone X  using OmniPeek.  Truth be told, that post was a little bit like the latest 'Spider-Man' sequel: attention-grabbing title, some interesting content, but ultimately nothing consequential.  And just as movie fans knew that Michael Keaton's flying bird character wasn't going to beat the lead superhero,  a lot of Wi-Fi folks already knew that Apple iOS devices use Protection (called a "TXOP" in the blog po

I defend Apple a lot.  When Network World wrongly accused  the original iPhone of flooding Duke University's network, I defended Apple .  (It was later found to be a Cisco problem.)  When a health care provider I was doing some work for blamed SIP-enabled iPhones for a VoIP problem, I eventually found out that the APs were to blame .  (The APs were failing to respond to WiFi frames tagged as "Background" QoS.)  Time and time again networking folks blame device makers like Apple, and time and time again the problem ends up being the network. There are times, however, when it really is Apple's fault.  When the network is operating just fine.  This is one of those times.  The problem is that I just don't know why. 802.11n (HT) and 802.11ac (VHT) networks operate in co-existence with first generation (802.11a/b/g, that is) WiFi a lot.  When that happens, the HT or VHT access point operates in mixed mode. There are all sorts of ramifications when a WiFi network