CCNA 2 Capitulo 2.1

CCNA 2 Capitulo 2.1

1. SWITCHING CONCEPTS

   • SWITCHING DOMAIN
     • COLLISION DOMAIN
       • HUB BASED ETHERNET SEGMENTS
         • DEVICES COMPETED FOR THE SHARED MEDIUM
         • ALL PORTS SHARE THE SAME COLLISION DOMAIN
         • A HUB INCREASES THE SIZE OF A SINGLE COLLISION DOMAIN.
       • SWITCHES BASED ETHERNET SEGMENTS
         • HOW IT WORKS WHEN YOU RECEIVE A BROADCAST FRAME ?
           • IT FORWARDS THE FRAME OUT EACH OF ITS PORTS
           • BROADCAST ALSO REDUCE NETWORK EFICIENCY
         • SWITCH OPERATE IN HALF DUPLEX
           • EACH SEGMENT IS ITS OWN COLLISION DOMAIN
         • SWITCH OPERATE IN DUPLEX FULL
           • ELIMINATE COLLISIONS / THERE ARE NO COLLISIONS
         • SWITCH EXTENDS / INCREASE A BROADCAST DOMAIN
           • ALL PORTS ARE IN THE SAME BROADCAST
             • SAME AS COLLECTION OF INTERCONNECTED SWITCHES
           • EACH PORT IS ITS OWN COLLISION DOMAIN
         • ETHERNET SWITCHES WILL AUTO-NEGOTIATE FULL DUPLEX, ALLOWING ADJACENT DEVICES TO ALSO OPERATE IN FULL DUPLEX.
         • FULL DUPLEX
           • INCREASES EFECTIVE BANDWIDTH
             • EXCEPT THE INGRESS PORT WHERE THE BROADCAST FRAME WAS RECEIVED
         • A SWITCH CREATES MANY SMALLER COLLISION DOMAINS
     • BROADCAST DOMAIN
       • ALL DEVICES ON THE LAN THAT RECEIVE BROADCAST FRAMES FROM A HOST ARE IN THE SAME BROADCAST DOMAIN
       • ROUTERS
         • SEGMENT / BOUNDARY / BREAK BROADCAST DOMAINS
         • ROUTERS DO NOT TRANSMIT BROADCASTS.
         • ROUTER DOES NOT INCREASE COLLISION DOMAIN
     • ALLIEVIATES NETWORK CONGESTION
       • FAST PORT SPEEDS
         • ACCESS LAYER SWITCHES
           • 100 / 1GBPS
         • DISTRIBUTION LAYER SWITCHES
           • 100 MBPS , 1GBPS AND 10GBPS
         • CORE LAYER AND DATA CENTER
           • 10GBPS , 40 GBPS AND 100GBPS
       • FAST INTERNAL SWITCHING
         • SWITCHES USE A FAST INTERNAL BUS OR SHARED MEMORY TO HIGH PERFORMANCE
       • LARGE FRAME BUFFERS
         • SWITCHES CAN LARGE MEMORY BUFFERS STORE MORE RECEIVED FRAME BEFORE HAVING TO START DROPPING THEM
         • THIS ENABLES INGRESS TRAFIC FROM A FASTER PORT (1000MBPS) TO BE FORWARDED TO SLOWER (100MBPS)
       • HIGH PORT DENSITY
         • HELP KEEP TRAFFIC LOCAL, WHICH HELPS ALLEVIATE CONGESTION.
         • LOWERS OVERALL COSTS
           • REDUCE THE NUMBER OF SWITCHES REQUIRED
             • EX : IF 96 ACCESS PORTS WERE REQUIRED ,
               • IF WOULD BE LESS EXPENSIVE TO BUY TWO 48 PORT SWITCHES
                 • INSTEAD OF FOUR 24 PORT SWITCHES
         • NUMBER PORTS AVAILABLE PORTS
     • INCREASE IN THE SIZE OF THE BROADCAST DOMAIN