18-07-2012, 02:29 PM
PRESENTATION ON BSNL BROADBAND
PRESENTATION ON BSNL BROADBAND.pptx (Size: 594.08 KB / Downloads: 77)
INTRODUCTION TO NIB
The Internet backbone refers to the principal data routes between interconnected networks and core routers in the Internet. These data routes are hosted by commercial, government, academic and other network centres.
It relies on the endpoints of communication to handle most of the processing to ensure data integrity, reliability, and authentication.
It is typically a fiber optic trunk line. The trunk line consists of many fiber optic cables bundled together to increase the capacity. The backbone is able to re route traffic in case of a failure.
DIGITAL SUBSCRIBER LINE(DSL):
Digital Subscriber Line (DSL) is a family of technologies that provides digital data transmission over the wires of a local telephone network.
The most commonly installed technical variety of DSL is ADSL which stands for ASSYMETRIC DIGITAL SUBSCRIBER LINE.
The data throughput of consumer DSL services typically ranges from 256 Kb/s to 40 Mbit/s in the direction to the customer depending on DSL technology, line conditions, and service-level implementation.
COMPONENTS OF DSL:
DSL CPEs: At customer premises. On end it connects telephone cable coming from exchange. At the other end, it connects to PC through Ethernet and Telephone through RJ-45 connector
DSLAM: called as DSL Access Multiplexer. It has a built in splitter which splits voice and data. While voice follows the normal conventional path through exchange, data is aggregated and up linked through Ethernet Port (Gigabit Ethernet for 480 port and Fast Ethernet for lower DSLAM)
LAN Switch: For aggregating multiple DSLAM and providing a common uplink.
SS: Called as Subscriber Service Selection System. When customer logs in he will be welcome with this customized screen from where he can select various range of service.
RADIUS: This in conjunction with BRAS authenticates customer, upload customer profile in the SS and keeps track of billing
LDAP: It stores customer database viz username, password and the default services that it can subscribe to.
Provisioning: This is the most critical components for ensuring quick delivery of service. It ensures end-to-end provisioning of service right from DSL CPEs to DSLAM.
CONNECTION PROCEDURE:
Physical connection must come first. On the customer side, the DSL Transceiver, or more commonly known as a DSL modem, is hooked up to a phone line. The telephone company(telco) connects the other end of the line to a DSLAM, which concentrates a large number of individual DSL connections into a single box.
The DSL transceiver performs a self-test. The DSL transceiver checks the connection between the DSL transceiver and the computer.
The DSL transceiver then attempts to synchronize with the DSLAM. Data can only come into the computer when the DSLAM and the modem are synchronized. During synchronization the light flashes; when synchronized, the light stays lit, usually with a green color.
ROLE OF DSLAM:
The DSLAM equipment at the telephone company (telco) collects the data from its many modem ports and aggregates their voice and data traffic into one complex composite "signal" via multiplexing. Depending on its device architecture and setup, a DSLAM aggregates the DSL lines over its Asynchronous Transfer Mode (ATM), frame relay, and/or Internet Protocol network .
The aggregated traffic is then directed to a telco's backbone switch, via an access network (AN) also called a Network Service Provider (NSP) at up to 10 Gbit/s data rates.
BROADBAND REMOTE ACCESS SERVER:
BRAS: called as Broadband Remote Access Server. First intelligent device in the whole chain. It terminates the customer session, authenticates, allot IP addresses and keeps track of user session for billing purposes.
A broadband remote access server (BRAS, B-RAS or BBRAS) routes traffic to and from broadband remote access devices such as digital subscriber line access multiplexers (DSLAM) on an Internet service provider's (ISP) network.
The specific tasks include:
Aggregates the circuits from one or more link access devices such as DSLAMs
Provides layer 2 connectivity through either transparent bridging or PPP sessions over Ethernet or ATM sessions
Enforces quality of service (QoS) policies
Service control module:
It is responsible for authentication and management of user access requests. It identifies legal users. It can extract and record the statistics of user data packets and online duration for implementing the traffic based or duration based accounting function.
MA5200G sends the user’s accounting information to the RADIUS server. BRAS allocates IP address through DHCP. It supports 4k to 96k IP addresses.MA5200G adopts packet binding technology. After user passes authentication It checks the binding relation of the IP address, MAC address, logical port and PPPoE session ID in each packet of this user and the packets that do not match will be discarded.