ACCESS TO THE NETWORK

ACCESS TO THE NETWORK

1. PROTOCOLS OF PHYSICAL LAYER

   • CONNECTION OF PHYSICAL LAYER
     • TYPES OF CONNECTIONS
       • Switch devices and wireless access points are usually two independent and dedicated devices within a network deployment
     • NETWORK INTERFACE CARDS
       • All wireless devices must share access to the airwaves that connect to the wireless access point and the ethernet does not need to share
   • PURPOSE OF THE PHYSICAL LAYER
     • PHYSICAL LAYER
       • provides the means of transport of the bits that make up a frame of the data link layer through the network means.
     • MEDIA OF THE PHYSICAL LAYER
       • basic formats of network media. The physical layer produces the representation and groupings by means of: Copper cable, Fiber optic cable, Wireless connectio
     • PHYSICAL LAYER STANDARDS
       • There are many government regulation organizations and private companies involved in the establishment and maintenance of physical layer standards
   • CHARACTERISTICS OF THE PHYSICAL LAYER
     • FUNCTIONS
       • they are three functional areas Physical components, coding and signaling in addition A common method for sending data is to use modulation techniques
     • BANDWIDTH
       • is the ability of a medium to transport data measures the amount of data that can flow from one place to another over a period of time.
     • PERFORMANCE
       • is the measure of bit transfer through the media for a certain period of time there are Factors that influence: The amount of traffic, The type of traffic, Latency
     • TYPES OF PHYSICAL MEDIA
       • It produces the representation and grouping of bits in voltages, radiofrequency and light pulses.

2. NETWORK MEDIA

   • COPPER WIRING
     • COPPER WIRING CHARACTERISTICS
       • The data is transmitted on copper cables as electrical impulses. A detector in the network interface must receive a signal that can be decoded successfully to match the signal sent.
     • COPPER MEDIA
       • Copper media are Unshielded twisted pair (UTP), Shielded twisted pair (STP) and Coaxial, These cables are used to interconnect the nodes in a LAN and wireless access points.
     • NON-ARMORED BRAIDED TORQUE CABLE
       • It is the most common network medium, it is used to interconnect network hosts with network intermediary devices, such as switches and routers.
     • ARMORED BRAIDED CABLE CABLE
       • provides better protection against noise than UTP cabling. combines shielding techniques to counteract EMI and RFI, and twisted wires to counteract crosstalk.
     • COAXIAL CABLE
       • There are two conductors that share the same axis, A copper conductor used to transmit the electronic signals. An insulation layer The second layer reduces the amount of external electromagnetic interference.
     • SECURITY OF COPPER MEDIA
       • Copper media is vulnerable to currents and unwanted voltages can cause damage to network devices and connected PCs or cause injury to personnel
   • UTP WIRING
     • UTP WIRING PROPERTIES
       • they depend exclusively on the cancellation effect and provide effective self-compliance of the wire pairs in the network means.
     • UTP WIRING STANDARDS
       • complies with the standards established jointly by the TIA / EIA. stipulates commercial cabling standards for installations and LAN environment
     • UTP CONNECTORS
       • it is used for a variety of physical layer specifications, one of which is Ethernet. ensure optimal operation with current and future network technologies.
     • TYPES OF UTP CABLE
       • Depending on the different situations, the UTP cables need to be assembled according to the different conventions: Direct Ethernet cable, Ethernet crossover cable, Console cable.
     • CHECKING UTP CABLES
       • After installation, a UTP cable tester should be used to measure the wiring map, cable length Loss of signal due to attenuation Crosstalk
   • WIRING OPTIC FIBER
     • PROPERTIES OF OPTICAL FIBER CABLING
       • It transmits data over longer distances and at higher bandwidths than any other network medium. The fiber optic cable can transmit signals with less attenuation
     • DESIGNS OF FIBER OPTIC MEDIA CABLES
       • It is composed of two types of glass (core and coating) and an outer protection shield (coating).
     • TYPES OF FIBER OPTIC FIBER MEDIA
       • The outstanding differences between multimode and single-mode optical fiber is the amount of dispersion. Dispersion refers to the spread of light pulses over time
     • OPTICAL FIBER CONNECTORS
       • Two fibers are required to perform a full duplex operation since light can only travel in one direction through the optical fiber.
     • OPTIC FIBER CABLE TESTS
       • You can perform a quick and simple field test that involves lighting one end of the fiber with a powerful flashlight while watching the other end.
     • COMPARISON BETWEEN OPTICAL FIBER AND COPPER
       • The use of fiber optic cables offers many advantages compared to copper cables. Optical fibers are not electrical conductors
   • WIRELESS MEDIA
     • PROPERTIES OF WIRELESS MEDIA
       • provide the best mobility options of all media There are some areas such as coverage area, interference, security and shared media.
     • TYPES OF WIRELESS MEDIA
       • wireless data communications cover the physical and data link layers and with standards such as wi-fi, bluetooth and wimax
     • WIRELESS LAN
       • Wireless data technology allows devices to connect wirelessly through a LAN. Wireless Access Point (AP), Wireless NIC Adapters.

3. PROTOCOLS OF THE DATA LINK LAYER

   • PURPOSE OF THE DATA LINK LAYER
     • THE DATA LINK LAYER
       • The data link layer effectively separates the media transitions that occur as the packet is forwarded from the communication processes of the upper layers
     • DATA LINK SUBCAPES
       • The data link layer is divided into the LLC and MAC sublayers. The LLC sublayer communicates with the network layer, while the MAC sublayer supports various network access technologies
     • MEDIA ACCESS CONTROL
       • specify the encapsulation of a packet in a frame and the techniques to place and remove the encapsulated packet of each medium
     • PROVISION OF ACCESS TO THE MEDIA
       • Each network environment that packets encounter when traveling from a local host to a remote host may have different characteristics.
     • STANDARDS OF THE DATA LINK LAYER
       • They give standards and protocols Institute of Electrical and Electronic Engineers (IEEE) International Telecommunications Union (ITU) International Organization for Standardization (ISO) National Institute of Standards (ANSI)

4. MEDIA ACCESS CONTROL

   • TOPOLOGIES
     • CONTROL OF ACCESS TO THE MEDIA
       • The regulation of the location of the data frames in the media is under the control of the media access control sublayer
     • PHYSICAL OR LOGICAL TOPOLOGIES
       • Physical topology: refers to physical connections and identifies how terminals are interconnected Logical topology: refers to the way in which a network transfers frames from one node to the next.
   • WAN TOPOLOGIES
     • PHYSICAL TOPOLOGIES OF WAN COMMON
       • In general, WANs are interconnected through the following physical topologies: Point-to-point: Hub-and-spoke, Mesh and A hybrid
     • POINT TO POINT TOPOLOGIES
       • Point-to-point physical topologies connect two nodes directly
     • LOGICAL TOPOLOGIES POINT TO POINT
       • the logical point-to-point connection between two nodes may not necessarily be between two physical nodes at each end of a single physical link.
   • LAN TOPOLOGY
     • PHYSICAL TOPOLOGIES OF LAN
       • The physical topology defines how the final systems are interconnected physically such as the Star, Extended or Hybrid Star, Bus and Ring
     • HALF DUPLEX AND FULL DUPLEX
       • Duplex communications refers to the direction in which data is transmitted between two devices. Half-duplex communications limit the exchange of data to one address at a time,
     • METHODS OF CONTROL OF ACCESS TO THE ENVIRONMENT
       • Some network topologies share a common medium with multiple nodes Access by contention, Controlled access.
     • ACCESS BY CONTAINMENT: CSMA / CD
       • If the two devices transmit at the same time, a collision occurs. The two devices will detect the collision in the network, that is, collision detection (CD).
     • ACCESS BY CONTAINMENT: CSMA / CA
       • Whether it's an Ethernet LAN with hubs or a WLAN, contention systems do not scale well under intensive media use
   • DATA LINK FRAME
     • THE PLOT
       • The data link layer prepares the packets for transport through the local media by encapsulating them with a header and a trailer to create a frame
     • FIELD OF PLOT
       • This format gives physical signals a structure that nodes can receive and that can be decoded in packets at the destination.
     • LAYER DIRECTION 2
       • The data link layer provides addressing that is used to transport a frame through shared local media
     • LAN AND WAN SECTIONS
       • The difference in bandwidth usually results in the use of different protocols for LANs and WANs. which are Ethernet 802.11 wireless, Point-to-Point Protocol (PPP), HDLC and Frame Relay