I havent checked, but I dont know if you'll find anything at SINET other than reference to the GEA cablelink. NGA comes under OFCOMs domain. The term GEA is more to do with the OFCOM rules of Equivalence of Input thingy or whatever its called. I would imagine that OFCOMs site would be the best place to go to get a full explanation, but I'll attempt to give an overview:
- Access to the copper network (CGA) is done at the Inspan Handover frame where they are presented with the tie pair.
- Obviously there isnt a tie pair for the FTTC/FTTP NGA network to present to the CP because thats in the field at the DSLAM.. and the CPs cant access the DSLAMs where the other end of the fibre is so instead the SP purchases an aggregated cablelink at the OLT.
Theres a lot more involved and youre talking VLANS etc but basically OFCOM ruled that BT must also provide access to Openreach's Next Generation Network. The equivalent to LLU is VULA (Virtual Unbundled Local Access) and because its presented as Ethernet hence the term GEA. Thats all it is - access point for SPs to BT's Fibre part of the local Network.
The fact that its VDSL rather than ADSL doesnt make any difference when it comes to the CPE. The Ethernet part perhaps youre thinking of isnt OLT <--> customers premises. Its the Fibre between cab and the head-end exchange. That final bit is still copper and that totally belongs to Openreach for which there is no access for the SPs.
When it comes to termination of t'other end, nothings changed other than they no longer supply the modem, just like 10+ years ago they stopped supplying the frog modems. The consumers and SPs wanted self install and the option to purchase/supply their own modem/routers and so thats what is happening now. Demarcation point is still the NTE same as with adsl. Hope that makes sense