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Transport layer of the OSI model - Definition

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Transport layer This is the fourth layer of the OSI model. The data unit at this layer is known as segment. The network layer deals with source-to-destination delivery of individual packets and does not recognize any relationship between them. On the other hand, the transport layer ensures that the entries message reaches in order and handles error control and flow control at the source-to destination level. Transport layer receives data from the session layer .it divides the data into segments with each segment having its own header and passes this segment to the network layer. At the receiver side, transport layer receives packets from the network layer. It detaches headers from them and then reassemblies the segments into original message and passes that massage to the session later Responsibilities of transport layer are: ☼ Service-point addressing - there may be number of programs running at the same time on a computer. For this purpose, source-to-destination delivery should also
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Network layer of the OSI model - Definition

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Network Layer This is the third layer of the OSI model. The data unit at this layer is known as packet. There is no need of the network layer if the two communication devices lie on the same network. However, when the two devices are connected on different networks, network layer is essential for providing source to destination delivery of packets. Network layer receives data from transport layer. It adds header to the passes data to the data link layer. At the receiver said, network layer receives data from data link layer. It detaches header from the data and passes data to the transport layer. Responsibilities of the network layer are: ☼Logical Addressing - the data link layer provides physical addressing which is useful for a local network. When the packet is destined for a device outside the network, we require other addressing scheme to identify source and destination network layer adds header to the data that includes the logical address (IP address) of the source and destinati
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Data link layer of the OSI model : definition

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Data link layer : Data link layer is the second layer of the OSI model. It handles data transfer between network and physical layers. Data unit at the data link layer is called as frame. Data link layer receives data from network layer. It adds header and trailer to the data and passes data to the physical layer. At the receiver said, data link layer receives data from the physical layer. It detaches header and trailer from the data and passes data to the network layer. Responsibilities of the data link layer are: ☼ Framing – the physical layer delivers raw bits from the source to destination. During transmission, the value of the bits can change. It is also possible that the number of bits received by the receiver may be different from the number of bits sent by the sender. To resolve this problem, the data link layer organizes the bits into manageable data units called as frames. ☼ Physical addressing – Data links layer adds header to the frame which contains the physical address o
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Physical Layer of the OSI Model: Definition

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Physical layer is the first or the bottom most layer of the OSI model. This layer is used to establish or terminate a connection to a communication medium. It also defines the electrical and mechanical specifications like cables, connectors and signaling options of the medium Physical layer receives data from the upper layer called the data link layer. It converts the received data into bit system. The data is then transmitted through the medium to the receiver. At the receiving end, physical layer receives the data in bit format. It forwards the data to the data link layer.  Responsibilities of the physical layer: Characteristics of media - defines the characteristics of the interface which used for connecting the devices. It also define the type of the transmission media such as copper wire or fiber optic cable Encoding – define the encoding type .encoding means changing bit stream (0s and 3s) into signal. Before transmission, physical layer encodes the signal into electrical or op
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Computer Network | Layers of Open System Interconnection (OSI) Model

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OSI   model   consists of seven layers and provides standards for data communication. 1.       Physical   layer : physical layer is responsible for actual transmission of bits over the medium. It deals with the electrical and mechanical functio 2.      Data link layer : data link layer is responsible for node to node delivery of frames. 3.      Network layer : Network layer is responsible for end to end delivery of packets and routing. 4.      Transport layer : transport layers is responsible for end to end delivery of the entire message. 5.      Session layer : Session layer is responsible for establishing,managing and terminating sessions. 6.      Presentation layer : is responsible for translation, encryption and data compression. 7.      Application layer : application layer is responsible for providing access to the network resources
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Working with E-mail clients?

E-mail client is a program used to manage, send and receive e-mails ,organize meetings, arrange appointments and keep a contact list. Microsoft outlook is a software application for handling and organizing personal information such as e-mail messages,calendar,schedules,tasks,notes,contacts. Configure e-mail setting include security options,server settings and connection Microsoft outlook enables the user to create five types of e-mail accounts such as POP3,IMAP,HTTP, Microsoft exchange server and third party mail server based e-mail accounts Windows mail is an e-mail and newsgroup client included in windows vista which is the successor to outlook express user has to take the backup of e-mail before formatting a PC In windows7 you”ll find outlook stores the PST and OST,in c:\users\<Username>\AppData\local\Microsoft\Outlook in vista you'll find windows mail files in c:\Users\<username>\AppData\Local\Microsoft\Windows Mail. The user may encounter various problems while wor
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Types of computer networks explained

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Net work  is categorized as per the geographical area to be covered by the network.computer network includes : ☼  LAN        - Local Area Network ☼   WAN       - Wide Area Network ☼   WLAN    - Wireless Local Area Network ☼   MAN       - Metropolitan Area Network ☼  SAN        - Storage Area Network, System Area Network, Server Area Network, or sometimes Small Area Network ☼   CAN       - Campus Area Network, Controller Area Network, or sometimes Cluster Area Network ☼   PAN        - Personal Area Network Local Area Network (LAN) LAN is a computer network that spans over a small area.it connects computers and workstations to share data and resources such as printers or faxes.LAN is restricted to a small area such as home, office or collage. all the workstations, server and printer are interconnected with the help of a network device.printer can be used by other workstations The institute of electrical and electronic engineers(IEEE) in the United states of America developed a series of
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