Mobile wifi – a cautionary tale

A mobile wifi device can be useful, but it can easily become expensive

Being able to connect a computer to the internet via the “personal hotspot” feature of a mobile phone is very useful to me when helping my IT Support clients. Sometimes, though, and for reasons I can’t explain, it’s not possible to connect to the phone’s wifi. That is why I still carry a dedicated mobile wifi device with me when making client visits. This seems to offer better connectivity and it provides reassurance in a “belt and braces” way.

My mobile wifi device was getting very old and slow (just like me), so I recently succumbed to EE’s marketing blurb about renewing my long-expired plan, and ended up with a better deal and a new device. Not only that, but I was gobsmacked when DPD actually managed to follow delivery instructions and call me on the mobile when they were outside my door with my brand new device (that would, of course, have just gone through the letterbox if someone would just teach these delivery people how to effect that difficult manoeuvre).

So, I set it up, played with it for a while and eventually got back to what I was meant to be doing. An hour or so later I realised that I was still connected to the mobile wifi and not my router. Out of curiosity I checked how much I had used it in the previous hour and was horrified to discover that I’d used nearly 4gb of my 5gb monthly allowance in just one hour. I couldn’t understand it. I’d not done anything on the internet of any significance data-wise in that time.

I knew that Windows was aware that my mobile wifi is a “metered connection”. As such, it is supposed to be careful about not performing internet tasks (such as downloading updates) that would seriously eat into an expensive mobile allowance. Then I checked the “programs and features” option in Control Panel to see if there was any evidence there of any programs updating in the previous hour. Nothing. Next, I wondered if my Synology Network Attached Storage had done a big backup to OneDrive. No, that backup is continuous and I hadn’t recently done anything big.

Hmm. After more digging into my backup routines (which, of course, you forget about in the months since setting them up), I realised that I had a routine performing a periodic encrypted backup of essential files that sent the backup to my Dropbox account. And that was it – once a month and it chose that hour to do it. All 4gb of it.

I was very surprised that Dropbox would function like this on a metered connection, so did some digging and found that I’m definitely not the first person to fall into this trap. It seems that Dropbox is NOT aware of metered connections.

On further reflection, I also realised something else about mobile wifi. Uploads as well as downloads are counted as data used from the allowance. This has probably always been the case, but I assumed that only downloads are counted as that is how data allowances used to be calculated on metered broadband connections when we first had the internet. I think that was because almost all domestic internet traffic used to be downloads. That, of course, is no longer the case.

So, I learned a few things that day:

• Not to forget to switch back from a mobile wifi connection to a broadband connection as soon as possible
• To stay aware if using mobile wifi that some routines can gobble up your allowance in a flash
• That mobile wifi uploads are as expensive as downloads
• That DPD can actually follow instructions sometimes

PS: talk of DPD reminds me that I heard a good joke on “The News Quiz” recently to the effect that Amazon are no longer in the business of home delivery. These days, it’s more akin to fly-tipping.

(Last updated 13/07/2021)