Programming & Networking (MERN + Cisco + Microsoft)

OSI Model - Network Layer hello friends ,,,i am Vasu Birla once again ,,and today we are going to discuss another layer of OSI Model that is  Network layer. In Previous layer Data link layer we got the actual working and definition of single networks ,Data link layer defines boundary of a single network , but  when we talk about lots of Networks means Internet or Inter-networking then Network Layer tell us that how it works  how internet is functioning today. Network Layer - Network layer deals with the lots of network it convince us that how data , devices and networks can be accessed and managed in World wide web or in internet. Some Most important functions of the network layers are - Packets  Logical addressing  Internetworking  Routing  Error Handling & Diagnostics  1. Packets -   On the network layer PDU ( Protocol data-gram unit ) is Packets  it means  on this layer Data is available in the form of packets just like data link layer's PDU is frame  like

LLC vs MAC Sublayers  hello friends this is Vasu Birla and today we will know about sublayers of data link layer . As we discussed in the last part that data link layer takes data from physical layer in form of bits (0,1) and check the transmission errors and then convert it in to frames. Data Link layer performs very important and complex task in our network. so for reducing of its complexcity it further divided in two parts or sub-layers. These are - LLC (Logical Link Control) Layer MAC (Media Access Control) Layer Logical Link Control Layer -   This sublayer provides services to Network Layer and  hides details of data link layer on network layer. It establish and control Logical links between local devices on network.  Today Most LAN technologies use this LLC protocol. LLC and MAC functions Media Access Control Layer- For Reducing the data traffic and conflict problem in network medium this MAC layer is used. MAC layer defines that how devices communicate on n

OSI Model - Data Link Layer  Hello friends once again i am vasu birla for discussing about second and most overloaded layer of OSI model  it is Data link Layer Data Link Layer -  It is the second layer from the bottom of OSI layer. Some Important functions of data link are following - Framing Error Detection Physical Addressing Flow Control   . Framing -   in the physical layer PDU (protocol data unit) is bit  it means in the physical layer data comes in form of bit or 0,1 form.  but later these different bits is converted in the frames combination of some 0s and 1s  the reason behind the framing is  easy error detection , so framing of data takes place in the data link layer.   Error Detection - When each layer of OSI pass data to other layer so it include header also ,, but the only data link layer attach header and as well as trailer . There is value in this Trailer  that is known as FCS or Frame check sequence.  FCS value is a calculated value of our frame whic

OSI Model - Physical Layer  Hello Friends i am Vasu Birla and today i will discuss about first Layer of OSI model ,, Physical Layer. Physical Layer   is the layer where actual data moves physically across the networks interfaces or components.   Physical layer specify standards about physical cables, devices and connecters. Some Important functions of physcial layer are:-  Transmission Media -  Which kind of medium used to transmit data it is wired or wireless and which kind of cables and connecters are used  , and how data are sent one devices to other with wired or wireless midium these all are comes under physical layer. (We will discuss in details about every transmission medium)   Transmission mediums Encoding & Signaling - Physical layer is also responsible for encoding and Signaling function. for exam those data are in form of bits or 0 and 1 form  so how these data can be sent to other devices and  what voltage levels should be for sending data in form of Sig