I was in one of the layoff classes of 2017.
Over the 15+ years I worked for O, layoffs were pretty much an annual or semi-annual thing. (They tend to do layoffs more than you'd think. They frequently do them in small enough numbers so that they don't have to report them.) I wanted to look for another position in the company because in my division they hadn't hired any U.S. based employees for years, they were shifting new positions and projects offshore, and no US-based employees in my division (other than managers) were getting promotions, raises, or bonuses. Over the years my immediate team had gone from 25+ US-based employees, down to 3 US-based employees and 5 offshore employees. And for several years managers had started openly talking to direct reports about how severance packages are calculated. So there was no secret that layoffs would be ongoing, and they wanted people to prepare for the possibility. (Also note that they tax severance payments upfront, and I believe I netted about 65% of the total dollar amount.)
I had to get my manager's approval to look for other positions w/in the company, and got his blessing in April or May. (I looked until my last day, but there was a hiring freeze in effect during this time.) Unfortunately, my manager told his manager that I was looking for another position in the company. I think that moved me up the list for layoffs, since management knew I was looking for a new job. I was happy in my current job, but I wanted to go to a division that was growing and was actively hiring. Also, I knew that many years ago, if O was downsizing a division they would find you a job in another division. Then they started giving people 6 months notice to find another job within the company on their own, or they were out. And now you're just out - they don't help you find another job, nor do they give you any time to find another job for yourself within the company.
The day my manager gave me my annual performance review, I was told I was being laid off, despite having a glowing review. He gave me a month's advanced notice, even though he wasn't supposed to. So I believe another poster was right, in that managers sit down around focal time and decide who's going to be laid off in the next round. Back in 2017, managers were not supposed to give people any notice, and just one day you were to be told it was your last day.
Looking back I made some big mistakes. I stayed with O even though I wasn't getting promotions or salary increases. At one point I put my current salary in an inflation calculator to find that I was actually making less money than when I was hired!! I stayed because I was allowed to work remotely 95% of the time, I liked the work, I liked my colleagues, and I knew my job and felt I was good at it. But when I had to find a new job, I think some potential employers saw me as an unmotivated desk jockey, who stayed in the same job, doing the same thing for 15 years until I was laid off/fired. I don't think being laid off hurt me as much in the eyes of recruiters/hiring managers, as did my staying in the same job with the same company for so long.
My advice for people still employed at O - if you want to find another job, look outside of O so as not to appear you're unhappy in your current position and possibly accelerate a layoff. If possible, look while you're still working - it's easier to find a job when you have a job, I wouldn't talk to any of your colleagues about looking for another position, because you don't want it to get back to your manager or their manager.
My advice to former O employees laid off- Even though I had advanced notice, when my last day came, it hit me hard. I can only guess how people feel when it comes from out of the blue. Know that you're not alone.
My advice to all - Don't stay at O (or any other company) more than 5 years unless you have something to show for it, like promotions, salary increases, etc. If you have been in the same position forever at the same company, be prepared to talk about why you stayed. I learned too late that loyalty to a company and a job are no longer valued. You need to job hop every 4-5 years to get promotions and salary increases.