iPhone fail to wake up and reconnect

rbnielsen
Head in the Cloud

iPhone fail to wake up and reconnect

Over a very long period of time, I've been noticing some different performance regarding iOS devices (me and wifeys iPhones) and my Meraki stack at home.

I often notice that after the iPhone has been "at sleep" for some time, and then open, it doesn't really reconnect. It is still associated to the SSID, as per the icon at the top, but I can't get any traffic through, and fails pings using Fing.

Not until I disable WiFi and enable it again, traffic again flows over WiFi.

 

The implication of this is that the iPhone looses connectivity to different streaming devices (my glorious Chromecast Audio).

 

Now I realize that iPhone, will disable it's NIC to conserve energy (Power Save Mode).

 

As soon as this occurred, I grabbed my Mac and took a packettrace on the channel with Airtool (v1.9.1).

 

Here comes the interesting part; in the trace I can see the air being flooded with Null Frames, which I can see stems from my iPhone. It's was as if it's informing my AP - continously - that it is going to sleep, and not getting a reply. 1 send, 6 retries; Send and two first retries at 6 Mbps rate, and the rest at 12 Mbps TX rate.

 

I'm wondering if anyone else has noticed this? I can't really decide if this is a bug or a feature, Apple or Meraki related.

Any feedback would be appreciated.

 

I've uploaded the .pcap here.

At the time of the packetdump, my Macbook and iPhone, was placed right next to eachother. So the packets received in the trace, should (sort of) reflect the same with regards to the iPhone.

 

Details;

iPhone MAC: f0:98:9d:c4:c2:2b / Apple_c4:c2:2b

Meraki AP: 32:56:ee:a0:51:a0

SSID: Winona Router

Security: WPA3-SAE

RRM: 5GHz only, Minimum bitrate 12 Mbps

 

At around packet 600 is where (I think), I disable and re-enable my iPhone NIC.

4 REPLIES 4
Inderdeep
A model citizen

Re: iPhone fail to wake up and reconnect

I never noticed that in my scenario will check if I get something but really good insight @rbnielsen 

Regards
Inderdeep Singh
www.thenetworkdna.com
rbnielsen
Head in the Cloud

Re: iPhone fail to wake up and reconnect

I'm still curious as to if anyone else has noticed the same.

BrandonS
Kind of a big deal

Re: iPhone fail to wake up and reconnect

I’ve been using full stack Meraki at my home with sever Apple devices for at least 4 years. The only issues I can recall are one that was pretty specific to packet loss using the RingCentral app and I have on rare occasion grabbed my phone and seen it appear to “catch up” on notifications from the last hour or so. That only happened a few times and it might been an expected result if a device being in low power mode. 


maybe your issue is around WPA3? 

 

rbnielsen
Head in the Cloud

Re: iPhone fail to wake up and reconnect

@BrandonS, I have honestly been wondering the same, if it was related to WPA3.

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