Hub strategy as mentioned in Investors calls, earnings calls, and town halls, is basically roof top consolidation. They want more people co located. And in the process of doing that old people leave or are RIFd they get to hire new young low cost people. In an SBG a hub might be Fort Mill SC for SPS or Morris Plains for PMT. basically if you aren't working at a major hub your job is at risk
Investors call in February said full HUB strategy will be implemented in less than 5 years and they have $500 million set aside for restructuring costs his year alone which they haven't even touched yet (as of February call)
Once April 20th earnings call is done expect them to start " acting with urgency", and announcing if you don't move to a hub you are out of a job by dd/mm/2018