AMathematicalTheoryofCommunication.pptVIP

Digital Subscriber Line- DSL Shannon Equation The larger the bandwidth the higher the transmission speed The stronger the signal, the higher the transmission speed The ‘louder” the noise, the lower the transmission speed Digital Subscriber Line (DSL) Standard telephone line (Cat 1 UTP) Capable of handling more than 3.1 Khz bandwidth DSL exploits Standard telephone line’s “extra capacity” to transmit data without disturbing the line’s ability to transmit voice Bandwidth usage for some Asymmetric DSL (ADSL) services: 0 - 4 Khz band for Voice conversation Upstream data transmission in 25 – 160 Khz band Downstream data transmission in 240 – 1500 Khz band DSL uses filters (splitters) to separate voice and data signals Typically a filter is needed for each analog device (telephone, fax, etc.) DSL loop extender DSL speeds are limited by the distance from the central office or DSLAM DSL loop extenders (or DSL repeaters) can be placed midway between the subscriber and the DSLAM to extend the distance and increase the channel capacity. Digital Subscriber Line (DSL) DSL speed: 256 kbps – 24000 kbps depending on DSL technology, line condition, service level, etc. Digital Subscriber Lines (DSLs) Asymmetric DSL (ADSL) Standard ADSL Downstream (to customer): Up to 8 Mbps over 2km UTP Upstream (from customer): 64 kbps or higher ADSL2 Downstream (to customer): 5 Mbps to over 12 Mbps Upstream (from customer): 1 Mbps to 3.5 Mbps Digital Subscriber Line (DSL) Digital Subscriber Lines (DSLs) HDSL (High-rate DSL) Needed in business. (ADSL primarily for home and small business access.) Maximum range: 3 kilometers Symmetric speed over voice-grade twisted pair HDSL: symmetric 768 kbps HDSL2: symmetric 1.544 Mbps or symmetric 2.3 Mbps Summary Questions On the user end, what elements are needed to establish a DSL connection? A DSL modem and filters/splitters to separate regular analog channel from the DSL data channels. ADSL provides for higher downstream speeds than upstream speeds. (a)?