DSL bonding
DSL (Digital Subscriber Line) stands for several transfer protocols for bit-by-bit data transfer with high bandwidths. Generally, DSL utilizes already existing copper line infrastructures on the last mile, which are then concentrated on the DSLAM (Digital Subscriber Line Access Multiplexer). "Behind" the DSLAM, more effective infrastructures, e.g. fiber optics networks, are used.The DSL characteristic concerning the applicability as business Internet connection or for site-to-site connections strongly depends on the version employed:
ADSL - Broadband DSL for end customers
ADSL is typically used for end-customer connections. The bandwidth is asymmetric, meaning up- and download differ severely from each other, generally at the ratio of 1:10. Current standard for ADSL is ADSL2+ with bandwidths of up to 20 Mbps (depending on annex and country). The possible bandwidth here depends on the length of the copper line, i.e. the distance between ADSL modem and ADSL DSLAM. Line latency (signal propagation time) is relatively low (generally 20-60 ms); however, stability and availability of ADSL are mediocre - too bad if it is to be used as single WAN connection for professional purposes. With ADSL, the copper line can be used for data transfer and telephony at the same time.EFM
Ethernet First Mile (EFM or Ethernet Internet) is a low cost leased line technology with huge cost savings over traditional fibre leased lines, bringing mission critical connectivity within the reach of small business. EFM provides symmetrical bandwidth at speeds of upto 20 Mbps with no contention.
