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Internet (OSI Model Layers (:one: Physical *Physically manage…

- - - - Routing
        Manage transport of packet
        
        Path finding
        How a packet go from node A to node B
        
        Routing table indicate to each node where to send a data packet
        
        updated created
        
        Congestion managment
        Manage network overloads
        
        Quality of Service (QoS)
        Manage QoS depending on parameters (provided in data packets or configured in hardware)
        
        Autonomous Systems (AS)
        Collection of routing prefix under a single administrative autority (eg. an Internet Service Provider (ISP))
        AS are interconnected with the Border Gateway Protocol (BGP), the internet main routing algorithm.
        
        Routing Prefix
        
        BGP
        
        Classless Inter-Domain Routing
        
        Point-to-Point Protocol (PPP)
      - If a connectionless transmission, perform data encapsulation and decapsulation
      - Error Handeling ICMP
      - IP allocation
        
        DHCP
        
        Manual Static Allocation
    - - routers
    - - IP Addresses
  - - - Voltage level and timing
        
        signal strenght is choosen considering Signal-to-nose ratio
      - Physical Data Rate
      - Maximum Transmission Distance
      - Connector Descriptions
      - Cable specification
        
        see cable impedance as well as electrical impedance
      - Radio Interface
        
        radio frequencies used
        
        signal strenght
    - - Modulation/Line Coding
        Process of going from digital bits to analog signal following specifications above
      - Bit Syncronisation
        Necessary to identify start and end of messages sent. Precisions in Bit and Frame Synchronization Techniques, Martin Probst , Lars Trielof
      - Flow Control
        Management of data transmission rate in order for the sender not to overflow the reveiver
      - Circuit Switching
        Creating a dedicated and exclusive route between the sender and the receiver
        NOT USED ANYMORE as packets allow communication without exclusive interfacing between nodes
      - Multiplexing
        Sending multiple signals over a shared medium
      - Signal processing
        
        Maximum likelihood sequence estimation
        Mathematic algorithm for data extraction from noisy data stream
        
        Pulse Shaping
        Process of creating optimal signals for transmission
        
        Equalization
        Algorithm based elimination of signals distorsions
    - - PHY chip
        Perform connection between a Data Link Layer device and the pysical medium transmitting information
  - - - Perform
        
        MAC Service Access Point
        Provide control abstraction over the MAC layer to LCC layer by taking requests (service primitives)
        Request eg. : MA_UNITDATA.request
        
        Channel Access Method
        Method used by MAC devices to use simultanously a single physical layer communication medium
        
        Queuing
        Managing overflowed transmission medium
        For extended approch on network delay, checkout that
        
        MAC Quality of Service(QoS)
        Parameters that describe and influence network efficiency, commonly associated to a specific hardware (eg. a router)
        Some protocols, as the Internet Protocol, include QoS instructions in their Protocol Data Unit.
        
        Maximum Packet Size
        
        Packet Transfer Rate
        
        Packet Error Rate (PER)
        Probability of an incoming packet having being corrupted
        
        Packet Transfer Delay
        
        Transmission Delay
      - Specifications
        
        Frame format
        Info based on ethernet standard
        
        Generate the frame composed of:
        
        Source MAC Adress
        
        Lenght indicator
        Number of bytes in the data field
        
        Data
        With a MTU – maximum transmission unit – of 1500 bytes
        
        Frame Check Sequence (FCS)
        Simple bits computation to ensure data integrity - see CRC, the Ethernet FCS for more.
        
        Destination MAC Address
        
        Preambule message
        *7 times "10101010" byte signal for receiver to:
        
        to start listening
        
        to achieve bit synchronization – clock settings, etc*
        
        Start-of-frame delimiter (SDF)
        10101011 byte, designed to brake the preambule pattern. Use to signal start of frame.
        
        Mac addresses
        6 bytes addresses identifying
        network hardware
        
        Organisationnaly Unique Identifier (OUI)
        First 3 bytes identifying the organization
        making the hardware
        
        I/G bit or M bit
        First bit identifying a unicast (0), or
        a multicast (1) address
        
        G/L bit or X bit
        Second bit, tells the address is a globally unique one (0) – identifying a unique physical netwok interface card (NIC) – or a locally administred one (1).
        
        Network Interface Controller (NIC)
        Last 3 bytes unique to the hardware
        
        Bit transfer protocols
        
        MTU
        
        Interval between Frames
        
        Collision detection and managment
      - Hardware
        
        Transmission Medium Controller
        Chip designed to control the associated transmission medium
    - - Perform
        
        Error Control
        
        Data integrity check
        Information arrived uncorrupted, usually performed with FCS of the Ethernet Frame
        
        Automatic Reapeat Request (ARQ)
        Check that frame correctly arrived at destination address
        Not implemented in the Ethernet Protoco
        
        Flow Control
        Manage transmission rate to prevent data sender to overflow data receiver (how can have a busy network or just a less powerful hardware)
- - - - Datagram
        
        Header
        
        Data
    - - Datagram
        
        Header
        
        Traffic Class
        
        Flow Label
        
        Payload Lenght
        
        Next Header
        
        Hop Limit
        
        Source Address
        
        Destination Address
        
        Version
        
        Data
- - - - Wired PAN
        eg. USB (printer)
      - Wireless PAN
        eg. Bluetooth (headset)