Broadband Internet usually refers to Internet connections that provide higher data rates than those available over an analog telephone connection.
A broadband Internet connection (often known as an xDSL connection) can be:
- ADSL broadband
- cable broadband
- VDSL broadband.
- HDSL broadband
- ISDN broadband
- SDSL broadband
- satellite broadband
The data rate (or speed) of practice broadband Internet access systems is limited partly by the fundamental characteristics of the channel (such as bandwidth and noise), and partly by design limitations of the modulation and channel coding systems used.
An important advantage of all broadband Intenet technologies is that they are “always on”. In other words, there is no need to dial-up to the Internet, and usually no charge for time connected. Charges are usually only made for data transferred. Connecting to the internet does not tie up the phone lline.
Information on GSM Architecture
A GSM network consists of the following components:
The GSM mobile station (or mobile phone) communicates with other parts of the system through the base-station system.
GSM Base station system (BSS):
Base transceiver station (BTS). The base transceiver station (BTS) handles the radio interface to the mobile station. The base transceiver station is the radio equipment (transceivers and antennas)
Base station controller (BSC):
The BSC provides the control functions and physical links between the MSC and BTS. It provides functions such as handover, cell configuration data and control of RF power levels in base transceiver stations. A number of BSCs are served by a MSC.
GSM Switching System:
Mobile services switching center (MSC). The MSC performs the telephony switching functions of the system. It also performs such functions as toll ticketing, network interfacing, common channel signalling, and others.
Home location register (HLR):
The HLR database is used for storage and management of subscriptions. The home location register stores permanent data about subscribers, including a subscriber’s service profile, location information, and activity status.
Visitor location register (VLR):
The VLR database contains temporary information about subscribers that is needed by the mobile services switching center (MSC) in order to service visiting subscribers. When a mobile station roams into a new mobile services switching center (MSC) area, the visitor location register (VLR) connected to that MSC will request data about the mobile station from the HLR, reducing the need for interrogation of the home location register (HLR).
Authentication center (AUC):
The AUC provides authentication and encryption parameters that verify the user’s identity and ensure the confidentiality of each call. The authentication center (AUC) also protects network operators from fraud.
Equipment identity register (EIR):
The EIR database contains information on the identity of mobile equipment to prevent calls from stolen, unauthorized or defective mobile stations.
Message center (MXE):
The MXE is a node that provides integrated voice, fax, and data messaging.
Mobile service node (MSN):
The MSN is the node that handles the mobile intelligent network (IN) services.
Gateway mobile services switching center (GMSC):
A gateway mobile services switching center (GMSC) is a node used to interconnect two networks.
GSM interworking unit (GIWU):
The GIWU consists of both hardware and software that provides an interface to various networks for data communications. Through the GSM interworking unit (GIWU), users can alternate between speech and data during the same call.
Operation and support system (OSS):
The OSS is the functional entity from which the network operator monitors and controls the system. The purpose of operation and support system is to offer support for centralized, regional, and local operational and maintenance activities that are required for a GSM network.
Definition: GSM, which stands for Global System for Mobile communications, reigns as the world’s most widely used cell phone technology. Cell phones use a cell phone service carrier’s GSM network by searching for cell phone towers in the nearby area.
Services Provided by GSM:
From the beginning, the planners of GSM wanted ISDN compatibility in services offered and control signalling used. The radio link imposed some limitations, however, since the standard ISDN bit rate of 64 kbps could not be practically achieved.
Using the ITUT definitions, telecommunication services can be divided into bearer services, teleservices, and supplementary services. The digital nature of GSM allows data, both synchronous and asynchronous, to be transported as a bearer service to or from an ISDN terminal. Data can use either the transparent service, which has a fixed delay but no guarantee of data integrity, or a nontransparent service, which guarantees data integrity through an Automatic Repeat Request (ARQ) mechanism, but with a variable delay. The data rates supported by GSM are 300 bps, 600 bps, 1200 bps, 2400 bps, and 9600 bps .
The most basic teleservice supported by GSM is telephony. There is an emergency service, where the nearest emergencyservice provider is notified by dialling three digits (similar to 911).
Group 3 fax, an analog method described in ITUT recommendation T.30, is also supported by use of an appropriate fax adaptor. A unique feature of GSM compared to older analog systems is the Short Message Service (SMS). SMS is a bidirectional service for sending short alphanumeric (up to 160 bytes) messages in a storeandforward fashion. For pointtopoint SMS, a message can be sent to another subscriber to the service, and an acknowledgement of receipt is provided to the sender. SMS can also be used in a cellbroadcast mode, for sending messages such as traffic updates or news updates. Messages can be stored in the SIM card for later retrieval .
Supplementary services are provided on top of teleservices or bearer services, and include features such as caller identification, call forwarding, call waiting, multiparty conversations, and barring of outgoing (international) calls, among others.
- GSM Architecture
- GSM Radio Link Aspects
- GSM Network Aspects
- GSM vs CDMA
File Transfer Protocol (FTP), a standard Internet protocol, is the simplest way to exchange files between computers on the Internet. Like the Hypertext Transfer Protocol (HTTP), which transfers displayable Web pages and related files, and the Simple Mail Transfer Protocol (SMTP), which transfers e-mail, FTP is an application protocol that uses the Internet’s TCP/IP protocols. FTP is commonly used to transfer Web page files from their creator to the computer that acts as their server for everyone on the Internet. It’s also commonly used to download programs and other files to your computer from other servers.
As a user, you can use FTP with a simple command line interface (for example, from the Windows MS-DOS Prompt window) or with a commercial program that offers a graphical user interface. Your Web browser can also make FTP requests to download programs you select from a Web page. Using FTP, you can also update (delete, rename, move, and copy) files at a server. You need to logon to an FTP server. However, publicly available files are easily accessed using anonymous FTP.
Basic FTP support is usually provided as part of a suite of programs that come with TCP/IP. However, any FTP client program with a graphical user interface usually must be downloaded from the company that makes it.
A router is a device or, in some cases, software in a computer, that determines the next network point to which a packet should be forwarded toward its destination. The router is connected to at least two networks and decides which way to send each information packet based on its current understanding of the state of the networks it is connected to. A router is located at any gateway (where one network meets another), including each Internet point-of-presence. A router is often included as part of a network switch.
A router may create or maintain a table of the available routes and their conditions and use this information along with distance and cost algorithms to determine the best route for a given packet. Typically, a packet may travel through a number of network points with routers before arriving at its destination. Routing is a function associated with the Network layer (layer 3) in the standard model of network programming, the Open Systems Interconnection (OSI) model. A layer-3 switch is a switch that can perform routing functions