CCNA 3 - Capitulo 7

CCNA 3 - Capitulo 7

1. WAN CONCEPTS

   • PURPOSE OF WANs ?
     • WAN TOPOLOGIES LOGICAL
       • POINT TO POINT TOPOLOGY
         • DEDICATED , LEASED-LINE CONNECTIONS
           • COORPORATE EDGE POINT TO THE PROVIDER NETWORKS (ISP)
         • LAYER 2 TRANSPORT SERVICES
           • THROUGH THE SERVICE PROVIDER NETWORK
         • POINT TO POINT CIRCUITO BETWEEN TWO ENDPOINTS
         • IS TRANPARENT TO THE CUSTOMER
           • IT SEEMS AS IF HERE IS A DIRECT PHYSICAL LINK BETWEEN TWO ENDPOINTS
       • HUB AND SPOKE TOPOLOGY
         • ENABLES A SINGLE INTERFACE ON THE HUB ROUTER TO BE SHARED BY ALL SPOKES CIRCUITS
         • SPOKES ROUTERS CAN BE INTERCONNECTED THROUGH THE HUB ROUTER
           • VIRTUAL CIRCUITS AND ROUTED SUBINTERFACES
         • SINGLE HOME TOPOLOGY
           • REPRESENT A SINGLE POINT OF FAILURE
       • DUAL HOMED TOPOLOGY
         • ADVANTAGE
           • REDUNDANCY ; LOAD BALANCING ; DISTRIBUTED COMPUTING AND PROCESSING
         • DISADVANTAGE
           • MORE EXPENSIVE TO IMPLEMENT BECAUSE REQUIRE ADDITIONAL NETWORK HARDWARE SUCH ROUTERS , SWITCHES
           • DIFFICULT IMPLEMENT BECAUSE REQUIRE ADDITIONAL AND MORE COMPLEX CONFIGURATIONS
         • PROVIDES REDUNDACY
       • FULL MESHED TOPOLOGY
         • THIS IS THE MOST FAULT TOLERANCE TOPOLOGY
         • CONNECT ALL SITES
           • MULTIPLE VIRTUAL CIRCUITS
       • PARTIALLY MESHED TOPOLOGY
         • CONNECTS MANY , BUT NOT ALL SITES
       • LARGER NETWORS DEPLOY A COMBINATION OF THESE TOPOLOGIES
     • LAN X WAN
       • LOCAL AREA NETWORK (LANs)
         • SMALL GEOGRAPHIC
           • CAMPUS NETWORK
           • HOME NETWORK
           • OFFICE NETWORK
           • BUILDING NETWORK
         • IS NO FEE
         • MANAGED
           • ORGANIZATION OR HOME USER
         • HIGH BANDWIDTH
           • ETHERNET AND Wi-Fi
         • INTERCONNECT LOCAL COMPUTERS , PERIPHERALS AND OTHER DEVICES
       • WIDE ARE NETWORK (WANs)
         • LARGER GEOGRAPHICAL
           • BETWEEN CITIES CONTRIES , CONTINENTALS
         • PROVIDE FOR A FEE
         • INTERCONNECT ENTERPRISE CAMPUS TO REMOTE LANs AT BRANCH SITES ... REMOTE USERS
         • IS A TELECOMMUNICATIONS NETWORK
         • OPERATE BOYOND THE GEOGRAPGIC SCOPE OF A LAN
         • LOW BANDWIDTH
     • CARRIER CONNECTIONS
       • DUAL CARRIER WAN CONNECTION
         • ORGANIZATION CONNECTS TO TWO SERVICE PROVIDER
         • ADVANTAGE
           • HIGH REDUNDANCY
             • CAN BE USED FOR REDUNDACY OR LOAD BALANCE TRAFFIC
           • NETWORK AVAILABILITY
           • SLAs SEPARETE WITH TWO SERVICE PROVIDERS
         • CAUTION : THE ORGANIZATION SHOULD ENSURE THAT THE TWO PROVIDERS EACH USE A DIFFERENT CARRIER
       • SINGLE CARRIER WAN CONNECTION
         • ORGANIZATION CONNECTS TO ONLY ONE SERVICE PROVIDER
         • DISADVANTAGE
           • BOTH SINGLE POINTS OF FAILURE
       • DESIGN IS HOW AN ORGANIZATION CONNECTS TO THE NETWORK
       • ORGANIZATION USUALLY SIGNs A SLA (SERVICE LEVEL AGREEMENT) WITH A ISP
         • THIS PROVIDES EXPECTED SERVICES AND RELIABILIY AND AVAILABILITY THE CONNECTION
       • THE SERVICE PROVIDER MAY OR NO MAY ACTUAL CARRIER
         • ISP IS THE REAL CARRIER:
           • THE SAME COMPANY OWNS THE PHYSICAL INFRASTRUCTURE
             • (FIBER, BACKBONE, EQUIPMENT).
         • ISP IS NOT THE REAL CARRIER:
           • THE ISP SELLS THE INTERNET SERVICE.
           • A DIFFERENT COMPANY (CARRIER) OWNS AND MAINTAINS THE PHYSICAL INFRASTRUCTURE.