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...

Wi-Fi Calling is here, and that fact is causing concern for some Wi-Fi folks.  Wireless LANs that were initially installed as a value-add may be tasked with carrying mobile, high-quality, always-on voice traffic. The 802.11 standard has had quality of service (QoS) protocols designed to accommodate voice since 2005, when the 802.11e amendment was approved.  That's good.   What's bad is that some voice applications are over-prioritizing their voice traffic, and it could lead to capacity limitations. First, some background on Wi-Fi QoS: The original 802.11 standard deigned that all Wi-Fi traffic would be created equally.  That is a GREAT thing for most Wi-Fi networks.  If some namby-pamby user whines to an admin, "Hey, why are you placing that AP in the OTHER room?  I want the AP closer to me," the admin can tell him (or her; women occasionally complain, too) "look, buck-o (or, buck-ess), Wi-Fi gives equal throughput to everyone who's connected.  ...

Voice over WiFi is scary.  Retries, packet errors (due to lots of Retries) and high latency (usually due to packet errors that happen because of lots of Retries) will murder a WiFi network's ability to handle Voice and leave your users screaming (not actually screaming) like they were cast in a horror movie (or, at the very least annoyed like a character from Office Space).  But there's one thing that sometimes scares people, but really shouldn't: Voice Arbitration.  It's not going to kill your WiFi voice calls.  In fact, it will almost certainly help. Arbitration is a process defined in the 802.11 standard .  Every device (client/station and AP) goes through it. The simplest way I can describe 802.11 Arbitration is like so: If your AP or station has heard a quiet channel for 37 microseconds (0.000037 seconds), then your AP or station transmits a frame (what most people call a packet, but I call a frame). If your AP or station has been hearing a busy ch...