BISDN is an extension of ISDN, that is, it has narrowband capability of ISDN but also the broadband capability.The purpose of BISDN is to achieve complete integration of services, ranging from low-bit- rate burst signals to high-bit-rate continuous real-time signals.B-ISDN ServicesThere are two types of B-ISDN services which are as follows −Interactive Services − Two-way exchange of information (other than control signalling information) between two subscribers or between a subscriber and a service provider.Distribution Services − Primarily one way transfer of information, from service provider to B-ISDN subscriber.These services are shown in the diagram format below −Technology DevelopmentsThe key technology ... Read More

Transmission impairment occurs when the received signal is different from the transmitted signal. As we know, a signal can be transmitted as Analog signal or it can be transmitted as a digital signal.In Analog signals due to transmission impairment the resulting received signal gets different amplitude or the shape. In the case of digitally transmitted signals at the receiver side we get changes in bits (0's or 1's).CausesThere are various causes of transmission impairments −NoiseDistortionAttenuationLet us understand them one by one.NoiseNoise is the major factor for the transmission distortion as any unwanted signal gets added to the transmitted signal by ... Read More

ISDN is also known as Integrated Services Digital Network. It is helpful in a wide range of services, for example, text (message), image, etc. It is capable of giving services and the foundation of telecommunication networks i.e. useful in the framework.It was also known as Integrated Digital Network because it is a digital technique that is used in switching as well as in transmission.Types of ChannelIt has three types of Channel.B-channelData-rate: 64 kbps.Required: for voice, information which has less data rate.D-channelData-rate: 16-64 kbps.Required: for packet switched data.H-channelData-rate − 1536 kbps or 1920 kbps data rate.Required − for video/ high-speed data ... Read More

The physical layer’s major function is to move data in the form of electromagnetic signals over a transmission medium. The data which is used by a person is not in a form that can be transmitted over a network.For example, a photograph has to be changed to a form that transmission media can accept. Transmission media works by conducting energy along a physical path.Both data and the signals that represent them can be either Analog or digital in form.Analog DataAnalog data refers to information which is continuous.For Example, an Analog clock which is having hour, minute, and second hands that ... Read More

Dense wavelength division multiplexing (DWDM) is a technology that multiplexes data signals from different sources so they can share a single optical fibre pair while maintaining complete separation of the data streams.DWDM can handle higher speed protocols up to 100 Gbps per channel. Each channel is only 0.8nm apart. Dense wavelength division multiplexing works on the same principle as CWDM but in addition to the increased channel capacity it can also be amplified to support much longer distances.The diagram given below represents the dense wavelength division multiplexing (DWDM) −Working of DWDMThe working of DWDM is explained below −DWDM modulates multiple ... Read More

Let us understand what a SONET/SDH Transmission in computer networking is.SONET/SDH TransmissionSONET stands for synchronous optical network. It offers cost effective transport both in the access area and core of the network.The transport services for the metro are provided by the optical layer. The optical layer has been now giving services for synchronous transmission and performance monitoring.Example − Telecom Network overviewThe SONET/SDH transmission is diagrammatically represented as follows −Its main role is that if some of the points in a network have not been working properly, the damaged sonnet has the capability to provide alternative points for the transport.Multiplexing enables ... Read More

Access Network is a type of network which connects the end system to the immediate router, physically in the path from the end system to any other distant end system. In telecommunications it is the network connecting subscribers to ISP.Some of the examples of the Access Networks are as follows −Home networkMobile networkAsymmetric Digital Subscriber Line (ADSL)Internet service provider (ISP)Some of access technologies are as follows −EthernetThe telephone lineWifiCable internet accessFiber to the home (FTTH)Dial-up modemDigital subscriber lineWide Area wireless Access networkNow let us try to understand some of the technologies in detail −Digital subscriber lineDigital subscriber line was previously ... Read More

Packet Switched service transfers the data from source to destination. Data is transferred on a type of network in which small units of data called packets are transferred. Each packet contains a destination address within it, where it has to be received.This type of communication between receiver & sender is connectionless. The internet is also a connectionless network. Most of the traffic over the internet uses packet switched service.Voice call over the internet is a type of packet switching, where each end of the conversation is divided into small packets & is reassembled later into a complete message. Packets are ... Read More

In a packet switching network, the data or information is transmitted between the sender and receiver in the form of packets. It does not require a dedicated physical path to transmit the fixed-size packet across the sun-network.If the size of information is large, then it is subdivided into multiple packets. On the destination side these multiple packets are assembled together into the original message, one type of packet-switched network is the datagram packet switched network.Types of Packet Switching NetworkThe packet switching network is of two types −Datagram packet switchingVirtual circuit packet switchingThe packet switching network is diagrammatically represented as follows ... Read More

The presence of congestion means the load is greater than the resources available over a network to handle. Generally we will get an idea to reduce the congestion by trying to increase the resources or decrease the load, but it is not that much of a good idea.There are some approaches for congestion control over a network which are usually applied on different time scales to either prevent congestion or react to it once it has occurred.Now let us see one of the techniques for congestion control which is termed as load shedding −Load SheddingIt is one of the approaches ... Read More