I am seeing a lot of people 5 years in with the company desperately trying to leave or got surplus and can't find a job. You are not learning anything worthwhile!!!
The key is to look at what you are doing now. If you are doing anything you can't take to another company or that opens up your option, it's time to leave now. No offense to the ATT veteran but if you are doing a job someone with 40 or 30 years of service is doing, you are missing out on learning skillsets that are currently on demand.
You should be doing Cyber Security, Actual Networking (network troubleshooting, heavy linux, configuring routers), cloud networking, or anything involving big data(Tableau). Better yet take those development courses incorporate them into your resume. Also get certifications.
In other for me to switch careers from this archaic garbage, I went home everyday and self learned until I found myself in an demand position. Even now I keep the same mentality of always training for my next job. It was depressing as hell seeing peers get promotion at other companies while I was on my butt depressed waiting to be culled.
AT&T is garbage!!