Computer Networks and Hardware essentails

 Network Communication

  • 1kbps=1 thousand bits
  • Kilobits per second is shortened to kb/s, Kbps or kbps
  • 1kb/s =1000bits 
  • 1Kb/s = 1024 bytes
ISP-internet service provider
  • common confusion between the KBps and  kbps is when it comes to bandwidth and download speed.
  • data transfer is calculate in kbps.
  • file size measure in Kilo Bytes and download is calculated based on how many Bytes per second are downloaded.
  • KBps and kbps are not interchangeable.
  • to calculate max download speed of a "X kbps" 
               Download KBPS speed= (Kbps value*1000/8)/1024

Components of networks
  1. NIC
  2. Switch
  3. Cable
  4. hub
  5. router
                 Hardware Components
  1. Network interface card
  • Its is a circuit board installed in a computer that provides a dedicates networks connection interface controller.
  • Network medium- cable plugs into the NIC and make the connection between a computer and rest of the network
            EX: wireless network and air waves
  • Interconnecting device-its allows two or more computer to communicate on the network without having connected directly to one another.
      Software Components
  • Network clients and servers
  • Network server software
          Layers of networking communication process



     Network Terminology
  • It is a description of how the device can communicate with the network.
  • It gives you the insight to diagnose problems.
  • It is important int he field of getting your services online and to run smoothly.
     Internetwork
  • It is a network collection of LANs tied together by device such as router.
         EX: Internet is the largest and most well known internetwork.

        Personal area network(PAN)
  • It is a group of network device that allows communication between various connection devices.
         EX: Bluetooth allows device like smartphone and headphone to connect wirelessly.

           Local area network(LAN)
  • It refers to a network that connect device with a limited geography area.
  • it allows to share resources and communicate with each other.ILAN has a short propagation belay than MAN and WAN.
  • It covers small areas.
          Metropolitan area network(MAN)
  • It covers larger area than LAN such as small towns, cities.
  • It connect two and more computers that reside within the same or completely different cities.

          Wide area network(WAN)
  • It covers a large area than LAN as well as a MAN such as country, continent, etc.
         EX: network of bank

  • Network- public network accessible only to authorized user within an organization.
  • Intranet- private networks that allows external parties to access certain parts of an organization's intranet.
            Router
  • It is networking device that connects multiple networks together and frame works data packets between them.
  • TCP/IP(Transmission Control protocol/ Internet Protocol): set of protocols used to communicate over the internet and other networks.
  • Protocol-is standardized set of rules for formatting and processing data.
  •  Protocols enable computers to communicate with one another.
  • IP Address - is unique numerical identifier assigned to each device on a network, used to identify and communicate with  other device.
     Public IP address
  • Identify you to the wider internet so that all the information you are searching for can find you.
  • External(global) reach
      Private IP address
  • Is used within a private network to connect securely to other device within that same network.
  • Internal(local) reach

       Packets and frames
  • Packets- chunk of data  with a source and destination IP Address to it.
  • Frames- a packets with the source and destination MAC address added to it.
  • Process of adding IP address and MAC addresses to chunk of data is called encapsulation.
       Client and server
  • Client is a computer hardware device or software that accesses a service made available by a server.
  • It is a network software on a computer that requests network resources from a server.

         Client operating systems
  1. Client operating systems
  • The OS installed on a computer.
        2. Client computer
  • To run user application and access network resources 
       3. Client software
  • softwire that requests networks resources from server software on another computer.

     Server is a computer becomes a sever when software is installed on it that provides a networks service to               client computers.

       1.Sever OS 
  • Installed on a computer designed to share networks resources and provide other networks services.
      2. Server computer 
  • To give client computer access to network resources and services.
     3. Sever software
  • Responds to request for networks resources from client software.


B02: INTRODUCTION TO NETWORKS DEVICE

1.Repeater
  •  it regenerates the signal over the same networks before the signals becomes too weeks.
  • when the signal becomes week, they copy the bits by bits and regenerate it at the original strength.
  • it is 2 ports device.
  • repeater can  resolved some problems with a device.
2. hub
  • it is multiport repeater.
  • it connects multiple wires from different branches.
  • hubs cannot connected filter data, so data packets are sent to all connected device.
  • collision domain is the domain in which, the signals that are transmitted by the devices over the networks collied with each other.

Types of hub
1. Active hub
  • they have their own power supply and sever both as repeater as well as connecting center.
  • due to their regenerating capabilities , they can extend the maximum distance between nodes, thus increase the size of LAN.
2.Passive Hub
  • it connects nodes in star configuration by collecting wiring from nodes. 
  • it is relay signals onto the networks without cleaning and boosting them.
  • they cannot extend the distance between nodes, they limits the size of the LAN.
3. Intelligent Hub
  • it is active hubs that provides additional networks management facilities.
  • they can perform a verity of functions of more intelligent networks devices like network management, switching, providing flexible data rates.

Switches
  • it is a multiport bridge with a buffer and a design that can boost its efficiency and performance.
  • it is data link layer device.
  • they can perform error checking before forwarding data.
  • broadcast domain-it is a domain that consists of all the devices that can receives a broadcast message that is sent by any other device which is present in the domain.

Router
  • it is a device like switch that routes data packets on their IP address.
  • it is mainly a Network Layer device.
  • it connect LANs and WANs together and have dynamically updating routing table.
  • it divides broadcast domain of host connected through it.
Network bandwidth-is amount of data that can be transferred in an interval. 

Bandwidth sharing- when all computer connected to the hub must share the amount of bandwidth the hub provided.



Network switches



Network switches- is a networking hardware that connects devices on a computer network by using packet switching to receives and forward data to the destination device.
  • it is multiport network bridge that uses MAC addresses to forward data at the data link layer pf the OSI model.

Switches indicator lights
  • switch have indicator light
  • switch have link status indicators and activity indicators.
  • it also have the indicator for whether the switch is operating in full-duplex or half-duplex mode.
  •  switches connected to one another that the LAN can grow beyond the limitation of ports in a single switch.

WAP(Wireless Access Points)
  • heart of wireless network is wireless access point(AP)
  • All the communication passes through the AP.
  • wireless LANs are attached to wired networks
  • mostly wireless network is used by small business' and home network.
  • an access point connects to a wired router, switch.  


NIC(network interface card)
  • provide connection from computer to medium.
  • most NIC is built into a computer's motherboard.
NIC and MAC Address
  • NIC manufacture ensure that every NIC produced has unique address.
  • MAC address is  stored in read-only memory(ROM) on the NIC.
NICs as Gatekeeper
  •  NIC check's the frame's destination and MAC address is to see whether it matches its's built-in MAC address.
  • NIC permits inbound communication if the destination MAC:
           1.Matches the NICs burned-in address
            2. is a broadcast address 
             3. NIC is in a special mode called promiscuous.
  • Unicast frame- when the destination MAC address  matches the MAC of the NIC.
  • Broadcast frame- when the destination is the broadcast address.
  • Promiscuous mode- turns off the  gatekeeper function and enables the NIC to process all frame it sees .

NICs indicator lights 
  • it shows the status information.(usually a link indicator and activity indicator)
  • the link light is green when the NIC connect to the network medium.
  • there is separate light for each speed that determine the what speed NIC  is connect to the hub or switches.
  • sometime there is a different color for each speed, such like amber for 100Mbps
  • and green for 1000Mbps
 NIC driver
  • drivers are computerized instructions and information that are required for a NIC card to be operational after it is installed into or connected to a computer.
Wireless NICS
  • It is connects to wireless network, such as Bluetooth or Wi-Fi.
  • it is connect to network using service set identifier (SSID)
Router
  • connect LANs together to create an internetwork.
  • it is a device that enable to multiple LANs to communicates with one another.
Difference between router and switches are:
  1. router connects LANs                                                         1.switches connect computer to form LANs
  2. router works with logical(IP) addresses                                2. switches work with physical(MAC) address
  3. router works with packets.                                                      3.switches works with frames
  4. router don't forward broadcast.                                                4.switches  forwards broadcast
  5. router use routing tables.                                                            5.switches use switching tables



Comments

Post a Comment