I am streaming , how can I play music when provider goes down.

I'm a network engineer/architect by profession,  just wanted to get that out of the way.

The easiest answer to your question,  your internet provider connects through your WAN which is external to your local network,  LAN. Even if your WAN is down you should still have access to your local resources, ( music server). Unless your software needs to see an external WAN heartbeat,  you should be able to access your locally stored music..

Ok thank you gumbedamit I have 1Terabyte of Flac files on my Solid state 

drive  how could I access this to play ,and how can I pick out the music i want to play if say my ptovider Spectrum is down ?  
how can I choose ,access of the music ?

I am used to pick everything on my iPad .if I bought say a Innuous with a hard drive 

and streaming can I then maybe do this easier then my purpose built , computer ?

thanks all for the assistance 🙏👍

that is one of the reasons I have kept my legacy sources(turntables, CD, players, and even iPod docks). That is also why I have kept my albums and CDs.

Yes, buy a cd player.  

You "network guys" are something else.

I did home automation, distributed audio, home theater, security, etc. for several decades. Each time I’d attend (required) vendor training sessions on networking gear, I considered myself an expert for at least 45 minutes after the session was over. Then it was back to what I did best: configuring devices that made noise, or produced an image.

It could have been childhood trauma, but the "networking" section of my brain didn’t fully develop. You guys who can sling data around a home (without dropouts and dead spots) deserve accolades and (financial) rewards. You’ve earned it. These days, devices that make noise or produce images don’t make noise or produce images without a stable, reliable network. You win!