Understanding Wifi interfaces and changes in Stretch

[Bodestone]

Firstly I am sorry for forgetting to bookmark posts I have seen and so forgetting the exact terminology of some of the following.

I have a Pi Zero with Raspbian Stretch and an additional USB wifi adapter.
My plan was to use this for connection to configure while making the built in wifi adapter an access point.
The trouble is that when plugged in the USB adapter becomes wlan0 not wlan1.

I came across posts about a change in stretch where interfaces were defined by a numeric (or slphanumeric) ID instead of wlanX to remove the ambiguity which would be great. At the time I only had one adapter but even following the instructions it always registered as wlan0 but I left it until I had 2 working adapters in case that was when it kicked in.

It still hasn't and now I can't remember the term to search for. I think it was something like Identifiable Interfaces.

I don't need static IPs I just need to insure that any config I add refers to a specific interface rather than a transient wlanX which could vary depending on what is plugged in.

There was a post (https://www.raspberrypi.org/forums/view ... p?t=212317) that said /etc/network/interfaces.d should not be configured. All the file has is the source-directory entry and the directory is empty.

The supplicant file defines connection information, currentl with no interfaces specified so both interfaces connect to the same wifi point.

Hopefully someone can be of help.

Thanks.

[B.Goode]

Predictable Network Interface Names is probably the keyphrase to search for.

Introduced as the default with Raspbian Stretch in August 2017 and disabled (and made optional via a setting in the raspi-config utility) in September 2017.

[Bodestone]

Thanks for that. I must have had a blindspot when I looked in raspi-config last time.

I enabled it but though the USB adapter gained its unique name the onboard wifi was called wlan1.
Shutting down, removing the USB and staring up it became wlan0.

Very strange.

[Bodestone]

I've just loaded the June Stretch image (latest available for download) and completing only the most basic config needed, when I enable prefdictable NI names it does not affect the built in wifi on the zero.

It does do the USB ethernet adapter but that cannot configure. It is Realtek and another USB Realtek wifi adapter I had, supposedly tested on Raspbery Pis also did not work so I don't know if there is a driver issue in Stretch for Realtek or something with the Pi Zero.

This is getting quite frustrating. I accidentally bought a Pi 3, SmartPi TouchFrame and screen so will run tests on the hardware there but the main problem (Zero built in WiFi not obeying predictable names) cannot be tested elsewhere.

[Bodestone]

OK, so Pi 3 new Stretch build (setting recognisable before or after upgrade) still does not apply recognisable name to built in wifi.
It also suffers the issue of changing between wlan0 and wlan1 depending on whether a USB addapter is plugged despite the USB adapter following recognisable conventions.