Ummm. I'm not too sure about Daisy's explanation
The BT 21st Century Network (21CN) is designed to provide an enhanced broadband experience in comparison to that which was previously available with BT and LLU operator SMPF (single metallic path) services.
BT's 21CN network is an integrated phone and data network using TCP/IP and eliminating ATM from the backhaul services. In particular, it is designed to work with and through
SMPF, not to replace it.
Part of the 21CN rollout is a service known as Fibre To The Cabinet (FTTC).
Sort of, but only "sort of".
Delivered across BT’s Next Generation Network this (FTTC) service offers connectivity based on VDSL2 technology, ...
That's where the "sort of" comes in. FTTC is part of
Next Generation Access, rather than "delivered across" it. Nor does FTTC have any need whatsoever of BT's 21CN network, though the BT Wholesale WBC/WBMC/IPSC products (which most ISPs use) do go through it. TalkTalk FTTC does not.
...VDSL2 technology, providing higher line rates of up to 40Mbit/s downstream and a choice of either 2Mbit/s or 10Mbit/s upstream. This is achieved by running fibre to the local BT street cabinet where the MSAN (Multi-service access node) is located. Placing the MSAN into the street cabinet which is connected by fibre to the BT 21NC exchange, as aopposed to delivering a broadband service over copper from the local premise to the exchange means the service is not as susceptible to the bandwidth “slow down” created by the noise from copper running over longer distances.
Source Fibre to the Cabinet
That bit is fair enough. I'm not sure FTTC cabinets contain MSANs though, I believe they are DSLAMs.
Edited by RobertoS (Thu 03-Nov-11 22:42:39)