CCNA - Capitulo 14.1

CCNA - Capitulo 14.1

1. TRANSPORT LAYER

   • USER DATAGRAM PROTOCOL (UDP)
     • CHARACTERISTICS
       • MORE FAST TCP
         • FAST IMPORTANT
           • VOIP
           • DNS
       • DOES NOT REQUIRE
         • ACKNOWLEDGEMENTS
       • BEST EFFORT
         • IS NO ACKNOLEDGMENT THAT THE DATA ID RECEIVED AT THE DESTINATION
       • DATA
         • DELIVERS AS IT ARRIVES
         • DOES NOT RESEND LOST
         • DATA IS RECONSTRUCTED IN THE ORDER THAT IT IS RECEIVED.
       • SEGMENTS THAT ARE LOST
         • ARE NOT RESENT
       • CONFIABILITY > APPLICATION
         • APPLICATIONS THAT HANDLE REABILITY THEMSELVES
           • EX : SNMP , TFTP
         • THE APPLICATION MUST IDENTIFY THE PROPER SEQUENCE
         • AND DETERMINE HOW THE DATA SHOULD BE PROCESSED
       • LOW OVERHEAD
       • DOES NOT PROVIDE
         • SESSION ESTABLISHMEN
           • STATELESS
         • REALIABILITY
         • FLOW CONTROL
       • DATA UPLAYER
         • ENCASULATE IN DATAGRAMS
     • HEADER 4 FIELDS - 8 BYTES (64 bits )
       • SOURCE PORT ( 16 bits OR 2 BYTES )
         • SOURCE APPLICATION
         • ALWAYS DYNAMIC
         • ALLOWS MULTIPLE CONVERSATIONS OCCUR SIMULTANEOSLY
         • ACTS IS A RETURN ADDRESS FOR THE REQUESTING APPLICATION
       • LENGHT ( 16 bits OR 2 BYTES )
         • UDP DATAGRAM HEADER
       • CHECKSUM (16 bits OR 2 BYTES )
         • HEADER ERROR DATAGRAM
       • DESTINATION PORT ( 16 bits OR 2 BYTES )
         • DESTINATION APPLICATION
         • WELL KNOW PORTS OR REGISTRED
       • HEADER IS SIMPLER THAN TCP
     • TREE TYPES APPLICATIONS BEST SUITED FOR UDP
       • LIVE VIDEO AND MULTIMEDIA APPLICATIONS
       • SIMPLE REQUEST AND REPLY APPLICATIONS
     • CONNECTIONLESS PROTOCOL
       • NO SESSION EATABLESHMENT
     • RFC 768
     • IMPORTANT
       • BY DEFAULT DNS AND SNMP USE UDP
         • EXCEPTION ?
           • DNS UTILIZES TCP IF THE DNS REQUEST OR RESPONSE
             • DATA IS MORE THAN 512 BYTES