Atul saxena EC-4 th year
What is Broadband Access ? Any data access rate more than 2Mbps is considered as broadband access. As per the recent broadband policy of Govt. of India, access rate over 256 Kbps will come under category of broadband access.
Why Broadband ? Fast development in information technology field has yielded in applications which are bandwidth hungry. Inclusion of more and more graphics and video content in applications require high speed access to network. Network operators are trying to carry real- time traffic like voice and live video over data infrastructure to facilitate a unified network for all type of traffic.
Broadband Access Options Different Broadband access technologies can be deployed by a network operator depending on resources, infrastructure and availability of technologies Wireline Access Wireline Access DSL Technology Cable Modem Power line broadband access (BPL) Optical fiber based solutions Optical fiber based solutions Metroethernet, RPR, EPON, Ethernet over SDH Wireless Broadband Access solutions Wireless Broadband Access solutions Bluetooth, WiFi, WiMAX, FSO, LMDS, MMDS, VSAT/DTH
Digital Subscriber Line (DSL) There are various flavors of DSL access over twisted copper (telephone) line. ADSL ADSL HDSL HDSL VDSL VDSL IDSL IDSL
Asymmetric DSL (ADSL) Allows simultaneous access to the line by the telephone and the computer In case of power/ADSL failure, data transmission is lost but basic telephone service will be operational Provides kbps upstream kbps upstream mbps downstream mbps downstream Can work up to a distance of 2.7 to 5.5 kms depending upon the speed required
ADSL Data Rate - Wire Size – Distance Data Rate Wire Size Distance Mbps 0.5 mm Feet 5.5 Kms Mbps 0.4 mm Feet 4.6 Kms 6.1 Mbps 0.5 mm Feet 3.7 Kms 6.1 Mbps 0.4 mm 9000 Feet 2.7 Kms
ADSL Central Office Home/Office ADSL CPE Curb ADSL up to 5.5 Km Splitter Data switch Voice Switch Twisted Copper Pair InternetInternet PSTNPSTN SPLITTERS DSLAM Customer can have down load speed Upto 6 MB (3.5 KM) and upload speed 640 Kbps. Telephone works even in Case of power failure. SHDSL Splitter
SDSL Symmetric Digital Subscriber Line Rate adaptive version of HDSL Does not support analog calls Works up to 3.7 kms on 0.5 mm dia cable Affordable alternative to dedicated leased lines SHDSL-Symmetric High-bit-rate Digital Subscriber Line is an further improvement over HDSL/SDSL and uses single phone line
VDSL Very-high Data-rate DSL Originally named VADSL (A –Asymmetric) but was later extended to support both symmetric & asymmetric Requires one phone line Supports voice & data Works between kms depending on speed
IDSL ISDN DSL-a hybrid DSL/ISDN solution Works over existing ISDN connection Increases ISDN speed from 128 kbps to 144 kbps
Cable Modem The cable network was designed to deliver TV signals in one direction from the Head-End to the subscribers homes Operators had to upgrade the cable network so that signals could flow in both directions One spectrum is used for the signals that move from the Head-End towards the cable subscriber
Cable Modem Another spectrum of signal frequencies are used for the signals that move from the cable subscriber towards the Head- End By replacing existing one way amplifiers with two way amplifiers Cable Operators are able to separate the upstream and downstream signals and amplify each direction separately in the right frequency range
What is a Cable Modem