DSLAM

A Digital Subscriber Line Access Multiplexer (DSLAM) is a network device located at the edge of an ISP's network, typically in a telephone company central office or street cabinet. It aggregates multiple customer DSL connections onto a high-capacity uplink, allowing the provider to deliver high-speed Internet access over existing copper telephone lines. At the customer premises, a DSL modem or customer premises equipment (CPE) on each line establishes a DSL connection to the DSLAM.

The DSLAM terminates the DSL signals from many subscriber lines, assigns each line a DSL profile (rate, modulation, and error protection), and multiplexes the individual connections onto a shared backhaul link to the ISP's backbone or edge router. The DSLAM supports various DSL standards such as ADSL, ADSL2+, VDSL2, and vectored VDSL2, depending on the deployed hardware and local loop conditions. It may also support channel bonding to increase throughput and vectoring to reduce crosstalk.

In FTTC deployments, the DSLAM is located in a street cabinet or dedicated cabinet connected by fiber or another high-capacity link to the central office. In some models, DSLAMs are integrated with a router/switch to provide IP connectivity, QoS, and subscriber management. The device interacts with line filters/splitters in the customer premises to separate voice from data traffic.

Management: DSLAMs are managed by the operator's management system, typically via SNMP or CLI, for provisioning, monitoring, and software updates. They include features such as QoS, traffic management, fault detection, and redundancy options to ensure reliable service.