CCNA - Capitulo 14

CCNA - Capitulo 14

1. TRANSPORT LAYER

   • TRANSMISSION CONTROL PROTOCOL (TCP)
     • CHRACTERISTICS
       • IDENTIFY APPLICATION
         • PORT NUMBER
       • RELIABLE / FLOW CONTROL
         • PROVIES SAME ORDER DELIVERY
           • TCP ENSURES SEGMENTES ARE RESSEMBLED
             • PROPER ORDER
         • SEND DATA AT AN EFFICIENT RATE
           • ACCEPTABLE BY THE RECEIVER
         • ACKNOWLEDGE
           • RECEIVED DATA
         • SEQUENCE DATA
           • WRONG ORDER
         • EX : NETWORK HOSTS HAVE LIMITED RESOURCES (MEMORY , PROCESSER )
       • ESTABLISH SESSION
         • STATEFULL
           • CONNECTION ORIENTED PROTOCOL
         • BEFORE TO FORWARDING ANY TRAFFIC
           • THREE WAY HANDSHAKE
             • NEGOTIATE THE AMOUNT OF TRAFFIC (TCP MSS)
               • CAN BE FORWARDED AT A GIVE TIME
       • CONVERSATION AND IS TRACKED SEPARATELY
         • MULTIPLE CONVERSATIONS
           • EX : WEB PAGE , E-MAIL , VOIP
       • ADD HEADER INFORMATION
         • 20 BYTES or 160 bits
       • RELIABLE DELIVERY
         • RETRANSMIT IF NECESSARY
           • ANY UNACKNOWLEDGED DATA
             • AFTER A CERTAIN AMOUT OF TIME
           • ANY SEGMENT CORRUPTED OR LOST
     • HEADER 10 FIELDS - 20 BYTES ( 160 bits )
       • SOURCER PORT (16 bits or 4 BITS )
         • SOURCE APPLICATION
         • HOST LOCAL
         • ALWAYS DYNAMIC PORT
         • ALLOWS MULTIPLE CONVERSATIONS OCCUR SIMULTANEOSLY
         • ACTS IS A RETURN ADDRESS FOR THE REQUESTING APPLICATION
       • SEQUENCE NUMBER (32 bits OR 4 BITS )
         • DATA REASSEMBLY
       • RESERVED ( 6 BITS )
         • FUTURE
       • WINDOW SIZE
         • NUMBER BYTES BE ACCEPTEDAT ONE TIME
       • CHECKSUM
         • ERROR CHECKING SEGMENT
       • URGENT POINTER
         • CONTAINED DATA IS URGENT
       • ACKNOWLEDGMENT NUMBER ( 32 bits OR 4 BITS )
         • DATA HAS BEEN RECEIVED
         • NEXT BYTE EXPECTED FROM THE SOURCE
       • BITS OF CONTROL
         • PURPOSE AND FUNCTION
           • TCP SEGMENT
       • HEADER LENGHT (4B)
         • DATA OFFSET
         • LENHT TCP SEGMENT HEADER
       • DESTINATION PORT (16 bits or 4 BITS )
         • DESTINATION APPLICATON
         • WELL KNOW PORTS OR REGISTRED
     • RFC 793
     • HEADER - OPTIONS
       • MAXIMUM SEGMENT SIZE (MSS)
         • STANDARD IPV 4
           • 1460 BYTES
         • HOW IS IT DETERMINED?
           • SUBTRACTING THE IP AND TCP HEADERS FROM THE ETHERNET MAXIMUM TRANSMITION UNIT (MTU )
   • ROLE OF TRANSPORT LAYER
     • MULTIPLEXING
       • INTERCALATE
         • SEND THE SEGMENT
       • MULTIPLE APPLICATIONS CAN USE NETWORK
         • AT THE SAME TIME
           • EX : SEND EMAIL , OPEN MULTIPLE WEB PAGES
     • SEGMENTATION
       • FACILITATES DATA TRANSPORT
         • LOWER NETWORKS LAYERS
     • DATA RECEIVED IN THE UPPER LAYER
       • ENCAPSULATED SEGMENTS
   • LOGICAL COMMUNICATIONS BETWEEN
     • APPLICATIONS ON DIFFERENT HOSTS
   • OBS
     • SERVER CAN OFFER MORE SERVICE . EX : FTP , HTTP , SMTP
   • TRANSPORT LAYER X NETWORK LAYER
     • LAYER 3
       • STRUCTURE , ADDRESSING , AND ROUTING OF PACKETS
       • DOES NOT SPECIFY
         • HOW THE DELIVERY OR TRANSPORTATIONS OF THE PACKETS
     • LAYER 4
       • APPLICATION LAYER GENERATE
         • DATA THAT MUST BE EXCHANGED BETWEEN SOURCE AND DESTINATION
       • HAS NO KNOWLEDGE
         • TYPE OF MEDIA
         • PATH TAKEN BY HE DATA
         • CONGESTION ; SIZE THE NETWORK
       • HOW TO TRANSFER MESSAGES BETWEEN HOSTS
       • MANGAGING REABILITY REQUERIMENTS OF CONVERSATIONS