CCNA - Capitulo 7

CCNA - Capitulo 7

1. ETHERNET SWITCHING

   • ETHERNET FRAMES
     • ETHERNET ENCAPSULATION
       • COMMOM TECHNOLOGY
         • ETHERNET
           • CSMA/CD - PROTOCOL
             • BACKOFF ALGOTHNM
           • IEEE 802.2
           • IEEE 802.3
           • BANDWITCH
             • 10 Mbps
             • 100 Mbps
             • 1000 Mbps
             • 10000 Mbps
             • 40000 Mbps
             • 1000000 Mbps
           • LAYER 2 PROTOCOLS
           • LAYER 1 TECHNOLOGIES
         • WIRELESS LAN (WLAN)
           • IEEE 802.11
     • DATA LINK SUB LAYER
       • LLC SUBLAYER (802.2)
       • MAC SUBLAYER (802.3 , 802.11 OU 802.15)
         • DATA ENCAPSULATION
           • ETHERNET FRAME
             • INTERNAL STRUCTURE FRAME
           • ETHERNET ADDRESSING
             • SOURCE AND MAC DELIVER
           • ETHERNET ERROR DETECTION
             • FRAME CHECK SEQUENCE (FCS)
         • ETHERNET FRAME FIELDS
           • PREAMBLE (7 BYTES) / START FRAME DELIMITER FIELDS (1BYTES)
             • SYNCRONIZATRION SENDING AND RECEIVING
             • THE FIRST EIGHT BYTES . GET READY TO RECEIVE A NEW FRAME.
             • OBS : NOT INCLUDED SIZE OF THE FRAME
           • DESTINATION MAC ADDRESS (6 BYTES)
             • UNICAST , MULTICAST OU BROADCAST
             • DESTINATION NIC
           • SOURCE MAC ADDRESS (6 BYTES)
             • ALWAYS UNICAST
             • SOURCE NIC
           • DATA FIELD (PAYLOAD)
             • ENCAPSULATED DATA FROM A HIGHER LAYER (DATA , TCP , IP )
             • WHATS IS PAD ?
               • INCREASE ADDITIONAL BYTES MINIMUM SIZE. (64 BYTES )
             • FRAME 64 BYTES
               • LESS ?
                 • HUNT FRAME
                   • DISCARD
             • MINIMUM DATA LAYER 3
               • 46 BYTES (MTU MINIMUM )
                 • 20 TCP + 20 IP + 6 BYTES DATA (TCP MSS )
                   • + 18 BYTES ETHERNET HEADER + 4 BYTES FCS/CRC
             • MAXIMUM DATA LAYER 3
               • 1500 BYTES
                 • 1460MSS + 20 TCP + 20 IP +
             • MAXIMUM DATA LAYER 3
               • 1500 BYTES (MTU MAXIMUM)
                 • 20 TCP + 20 IP + 1460 BYTES DATA (TCP MSS )
                   • 1500 BYTES + 14 BYTES ETHERNET HEADER + 4 BYTES FCS/CRC= 1518
                   • 1500 BYTES + 14 BYTES ETHERNET HEADER + 4 BYTES VLAN + 4 BYTES FCS/CRC= 1522
           • ETHERTYPE / LENGHT (2 BYTES)
             • CONTAINS THE ENCAPSULATED DATA FROM A HIGHER LAYER
               • 0x800
                 • IPV4
               • 0x86DD
                 • ARP
               • 08X806
                 • IPV6
           • FRAME CHECK SEQUENCE FIELD (FCS) 4 BYTES
             • DETECT ERRORS IN A FRAME
               • USES CYCLIC REDUNDANCY CHECK (CRC).
             • VERIFY INTEGRITY
           • MINIMUM ETHERNET FRAME - SIZE
             • 64 BYTES
               • COMPOSE
                 • DATA
                   • 46 BYTES
                 • SOURCE / DESTINATION MAC
                   • 12 BYTES
                 • FCS
                   • 4 BYTES
                 • TYPE / LENGHT
                   • 2 BYTES
           • MAXIMUM ETHERNET FRAME - SIZE
             • 1518 BYTES (WITHOUT VLAN)
               • MORE ? JUMBO "GIANT FRAME"
                 • DISCARD
             • 1522 - WITH VLAN
         • ACCESSING THE MEDIA
   • NOTE : SWITCH DO NOT REQUIRE ACCESS CONTROL THROUGH CSMA / CD