Local loop unbundling

Written on 9:56 AM by ooe

As a result of Oftel's desire to promote competition at all levels of interconnection, in August 2000 Oftel mandated full unbundling of BT's local loop. Local loop unbundling (LLU) enables other operators to rent space in BT's exchanges, lease local access lines, and upgrade them with DSL technology to provide a range of higher bandwidth services to the end customer.

With LLU the competing network operator simply uses BT's access line and can operate both POTS and broadband services for the customer. LLU requires the operator to provide all equipment in the exchange and indeed the rest of the network in order to support the services offered to the users; though obviously it is possible for these operators to buy part of the capacity they need for their network from BT or other network operator.

There is little restriction in the equipment that can be used other than the requirement for the transmissions from the equipment to comply with the Access Network Frequency Plan (ANFP). More detail of the ANFP is covered in Chapter 4. The reason for this requirement is that it prevents unwanted interference that could affect equipment using other copper pairs in the same cable, or indeed interference that could affect any other equipment in the vicinity. The other purpose of the ANFP is that by identifying acceptable limits for transmission, it also identifies levels of emission that must be tolerated by the equipment.

With such a broad range of options, it is impossible to describe how an operator might use local lines to support broadband services, apart from the fact that they could simply replicate one or more of the above broadband products.

Related to LLU, is the requirement for shared access. In October 2000, Oftel published a consultation document entitled ‘Access to Bandwidth: shared access in the local loop’. This document discussed arrangements under which just the higher bandwidth of local access lines could be made available to a competitor. It differs from the LLU product already available in that the competing operator can lease the spectrum on the copper pair so to provide equipment such as ADSL, without leasing the POTS part of the spectrum. Hence, a competitor could offer ADSL based services whilst BT offer POTS over the same copper pair. 5.7