local loop (LL)
Local loop ( LL), access line( AL) or subscriber line( SL) is the term used to describe the subscriberline in the subscriber connection area between the exchange and the connected subscriber set. The entire connection area is also referred to as the last mile.
In the case of the public telephone network, it is the geographical area between the local exchange and the switching point in the building; this can be the access point or the subscriber line( TA). In traditional wireline technology, a main cable runs from the local exchange(OVSt) to the cable distribution frame(KVz). From there, the branch cables lead to the end distribution box(EVz), to which the end station lines to the telecommunications connection box are connected.
In other network configurations, the network switching point can be the access node or the distribution box on the sidewalk. In the connection area, FTTx technologies such as Fiber to the Curb( FTTC) or Fiber to the Building( FTTB) are predominantly used in addition to classic copper cabling. With copper cabling, small distances of up to a few kilometers can be bridged; with optical transmission technology, the expansion range is many times greater. The connection range is precisely defined in terms of attenuation, which may be 8.2 dB, loop resistance with a maximum of 1,200 ohms, and the number of connection units. In Germany, these values generally result in a geographical area of approximately 5 km radius around a local exchange. With xDSL technologies, data rates of 50 Mbit/s and more can be achieved over 1 km thanks to vectoring and line bonding with VDSL2 and ADSL2+.
Other technologies for the access area include wireless technologies: Mobile networks with high data rates such as Long Term Evolution( LTE), directional radio, satellite communications, WiMAX, WLL networks and spread spectrum technology. Furthermore, a proposal from IEEE 802.3ah is up for discussion, which provides for Ethernet in the connection area, Ethernet in the First Mile( EFM), EtherLoop, Long Reach Ethernet( LRE) and HomePNA.