текст 6 задания 19-20
.docx19
ASCII – American standard code for information exchange
SONET, SDH – synchronous digital hierarchy
OAM&P – operations, administration, maintenance and provisioning
ATM – asynchronous transfer mode
ADSL – asymmetric digital subscriber line
20
Broadband access and service
Transmission is now done via fiber, information is a string of 1’s and 0’s.
There are not enough coding schemes, most popular – SONET, ATM, ADSL
SONET
For optical communication. Defines technology for carrying mant signals of different capacities through a synchronous optical hierarchy.
Governs interface parameters, formats, multiplexing methods and OAM&P for high speed transmissions. SONET rings – transmission in one direction, if there is a fault in equipment – reverse direction.
ATM
High performance switching and multiplexing technology, fixed length packets for different types of traffic.
Multiple streams of traffic can be multiplexed on each physical facility and sent to different destinations.
ADSL
Modem with sophisticated coding scheme. Over copper 6 Mb/s.
Advantage – target applications function with low upstream rate.
Nowadays transmission in telecommunications networks is digital in nature – information is presented in binary form as a string of 1’s and 0’s. Therefore they must be correctly arranged, take optimal routes and be transmitted at optimal speed…