GEA means generic ethernet access.
It's an Openreach term.
We buy GEA-FTTC and GEA-FTTP.
A provider buys a GEA Cablelink to connect each Openreach OLT/L2S to their backhaul.
GEA Cablelinks come in 1Gb and 10Gb options. A single cablelink can serve both FTTC* and FTTP customers but there's also now FTTP only L2S and cablelinks.
Openreach often offer discounts on FTTP only GEA Cablelinks so that the likes of Talktalk, Sky and Vodafone pay up and can actually serve the millions of new homes being passed with FTTP. It's a considerable outlay for providers to get national coverage which is why smaller providers like A&A use other providers backhaul.
When I refer to FTTC above that includes both VDSL2 and G.Fast.
Zen offer 3 choices of backhaul on many exchanges. BT Wholesale, Talktalk business, or their own "GEA" network, which they call Plexus.
On their control panel on Openreach they refer to their own network as GEA.
I often refer to GEA backhauls as BTw, TTB or Zen GEA, Sky GEA, etc, though they are all GEA.