HillsBD

  Software-Defined Networking (SDN) is a network architecture approach that enables the network to be intelligently and centrally controlled, or ‘programmed,’ using software applications. This helps operators manage the entire network consistently and holistically, regardless of the underlying network technology. Enterprises, carriers, and service providers are being surrounded by a number of competing forces. The monumental growth in multimedia content, the explosion of cloud computing, the impact of increasing mobile usage, and continuing business pressures to reduce costs while revenues remain flat are all converging to wreak havoc on traditional business models. To keep pace, many of these players are turning to  SDN  technology to revolutionize network design and operations. SDN enables the programming of network behavior in a centrally controlled manner through software applications using open APIs. By opening up traditionally closed network platforms and imp...

  A wide area network (also known as WAN), is a large network of information that is not tied to a single location. WANs can facilitate communication, the sharing of information, and much more between devices from around the world through a WAN provider. WANs can be vital for international businesses, but they are also essential for everyday use, as the internet is considered the largest WAN in the world. Keep reading for more information on WANs, their use, how they differ from other networks and their overall purpose for businesses and people, alike. As described above, wide area networks are a form of telecommunication networks that can connect devices from multiple locations and across the globe. WANs are the largest and most expansive forms of computer networks available to date. These networks are often established by service providers that then lease their WAN to businesses, schools, governments, or the public. These customers can use the network to relay and store dat...

Potential transformer is a voltage step-down transformer that reduces the voltage of a high voltage circuit to a lower level for the purpose of measurement. These are connected across or parallel to the line which is to be monitored. The basic principle of operation and construction of this transformer is similar to the standard power transformer. In common, the potential transformers are abbreviated as PT. The primary winding consists of a large number of turns which is connected across the high voltage side or the line in which measurements have to be taken or to be protected. The secondary winding has a lesser number of turns that are connected to the voltmeters, or potential coils of wattmeter and energy meters, relays, and other control devices. These can be single-phase or three-phase potential transformers . Irrespective of the primary  voltage rating, these are designed to have the secondary output voltage of 110 V. Since the voltmeters and potential coils of other m...

  Virtual Local Area Network or Virtual LANs (VLANs) are a logical group of computers that appear to be on the same LAN irrespective of the configuration of the underlying physical network. Network administrators partition the networks to match the functional requirements of the VLANs so that each VLAN comprises a subset of ports on a single or multiple switches or bridges. This allows computers and devices in a VLAN to communicate in the simulated environment as if it is a separate LAN. VLAN  is a custom network that is created from one or more local area networks. It enables a group of devices available in multiple networks to be combined into one logical network. The result becomes a virtual LAN is administered like a physical LAN. The full form of VLAN is defined as Virtual Local Area Network. The below topology depicts a network having all hosts inside the same virtual LAN. Without VLANs, a broadcast sent from a host can easily reach all network devices. Each and eve...

  A LAN, abbreviated from Local Area Network  is a network that covers a small geographical area such as homes, offices, and groups of buildings. Whereas a WAN, abbreviated from  Wide Area Network  is a network that covers larger geographical areas that can span the globe. An example of a widely used WAN is the Internet, which is a collection of tens of thousands of networks that connects tens of billions of devices. Local Area Networks predominantly use Ethernet technology, which is a group of networking technologies that dictate how data is transmitted over the physical media, with the most common media being CAT# cabling. Local Area Networks can use both Layer 1 and Layer 2 devices; Layer 1 devices include HUB’s and repeaters and the Layer 2 devices that can be used are switches and bridge devices. While LAN’s use Layer 1 and Layer 2 devices, WAN ’s operate using Layer 3 devices such as multi-layer switches and routers. LAN’s are ...

  The Junction Field Effect Transistor , or JFET, is a voltage controlled three-terminal unipolar semiconductor device available in N-channel and P-channel configurations In the  Bipolar Junction In transistor  tutorials, we saw that the output Collector the current of the transistor is proportional to input current flowing into The base terminal of the device, thereby making the bipolar transistor a “CURRENT” operated device (Beta model) as a smaller current can be used to switch a larger load current. The  Field Effect Transistor , or simply  FET  however, uses the voltage that is applied to their input terminal, called the  Gate  to control the current flowing through them resulting in the output current being proportional to the input voltage. As their operation relies on an electric field (hence the name field effect) generated by the input  Gate  voltage, this then makes the  Field Effect Transistor  a “VOLTAGE” operate...

  Using a transistor as a switch is the simplest application of the device. A transistor can be extensively used for switching operations either for opening or closing of a circuit. Meanwhile, the basic concept behind the operation of a transistor as a switch relies on its mode of operation. Generally, the low voltage DC is turned on or off by transistors in this mode. Both PNP and NPN transistors can be utilized as switches. A basic terminal transistor can be handled differently from a signal amplifier by biasing both NPN and PNP bipolar transistors by an “ON / OFF” static switch. One of the main uses of the transistor to transform a DC signal “On” or “OFF” is solid-state switches. Some devices, including LEDs, only require several milliamperes of DC voltages at the logical level and can be directly controlled via the logical gate output. High-power devices such as generators, solenoids, or lamps usually need more power to use transistor switches than the usual logic gate. ...