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INTRODUCTION TO NETWORK - Coggle Diagram

- - - - Providing a well-defined service interface to the network layer.
      - Dealing with transmission errors.
      - Regulating the flow of data so that slow receivers are not swamped by fast senders.
    - - 1 . Frame synchronization- Data are sent in blocks called frames. The beginning and end of each frame must be recognizable. Flow control-The sending station must not send frames at a rate faster then the receiving station can absorb them.
      - 2 . Error control- Any bit errors introduced by the transmission system must be corrected.
      - 3 . Addressing– On a multipoint line, such as a local area network (LAN), the identity of the two stations involved in a transmission must be specified.
      - 4 . Control and data on same link- It is usually not desirable to have a physically separate communications path for control information. Accordingly, the receiver must be able to distinguish control information from the data being transmitted.
      - 5 . Link management- The initiation, maintenance, and termination of a sustained data exchange requires a fair amount of coordination and cooperation among stations. Procedures for the management of this exchange are required.
- - - - a. Addressing
        
        IP addresses must
        be unique for identification purposes.
      - b. Encapsulation
        
        The protocol data units from the transport layer are encapsulated by adding IP header information including source and destination IP address
      - c. Routing
        
        The network layer provides services to direct packets to other networks. Routers selects the best path for a packet to take to its destination networks.
      - d. Decapsulation
        
        The destination host de- encapsulates the packet to see if it matches its
        own.
- - - - Data
      - Trailer
      - Header
  - - - Flags
        
        Identifies the beginning and end limits of the frame.
      - Data
        
        Contains the frame payload (i.e., packet header,segment header, and the data).
      - Addressing
        
        Indicates the source and destination nodes.
      - Control
        
        Identifies special flow control services such as QoS.
      - Type
        
        Identifies the Layer 3 protocol in the data field.
  - - - Point-to-Point Protocol (PPP)
      - ◦ HDLC
      - ◦ 802.11Wireless
      - ◦ Frame Relay
      - ◦ Ethernet
- - - - On a Cisco router, the show ip arp command
        is used to display the ARP table.
    - - On a Windows 7 PC, the arp –a command is used to display the ARP table.
- - - - Physical address (the Ethernet MAC address
      - Logical address (the IP address)
      - Example: PC-A sends an packet ti file server on the same network
        
        Ethernet frame contains:
        
        Destination MAC address
        
        Source MAC address
        
        IP packet contains:
        
        Source IP address
        
        Destination IP address
  - - - ◦ The destination IP address is that of
        the File Server.
      - The destination MAC address is that of
        Ethernet interface of R1.
- - - - The broadcast message is received by all the other devices in the LAN network.
        
        Now each device will compare the IP address of the destination with its own IP address.
        
        If the IP address of destination matches with the device’s IP address, then the device will send an ARP reply massage.
        
        If the IP address do not match then the device will simply drop the packet.
        
        The device whose IP address has matched with the destination IP address in the packet will reply and send the ARP reply message.
        
        This ARP replay message contains the MAC address of this device.
        
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