CCNA 3 - Capitulo 13 .1

CCNA 3 - Capitulo 13 .1

1. NETWORK VIRTUALIZATION

   • HYPERVISOR TYPE 2 (HOSTED)
     • A BIG ADVANTAGE OF TYPE 2 : CONSOLE SOFTWARE MANAGEMENT IS NOT REQUERED
     • EX : VIRTUAL PC , VMWARE WORKSTATION , VIRTUALBOX , VMWARE FUSION ...
     • WHATS IS HYPERVISOR TYPE 2 ?
       • IS SOFTWARE THAT CREATES AND RUM VMs INSTANCES
     • HOST MACHINE
       • THE COMPUTER ON WHICH A HYPERVISOR SUPPORT ONE OR MORE VMs
     • HYPERVISOR IS INSTALLED ON TOP OF THE OPERATING SYSTEM SUCH MacoS , WINDOWS , AND LINUX
   • HYPERVISORS TYPE 1 (BARE METAL)
     • INSTALLED DIRECLY ON THE HARDWARE
     • USED ON ENTERPRISE SERVERS AND DATA CENTERS
     • IMPROVE SCALABILITY , PERFORMANCE AND ROBUSTNESS
     • EX : VMWARE ESXI , MICROSOFT HYPER-V , XEN , KVM , CITRIX HYPERVISOR
     • INSTALLING A VM ON A HYPERVISOR
       • REQUIRES A "MANAGEMENT CONSOLE" TO MANAGE HYPERVISOR
         • THE MANAGEMENTE CONSOLE CAN CONSOLIDATE SERVERS , POWER ON OFF SERVERS AS REQUIRED
         • MANAGEMENT CONSOLE IS USED TO MANAGE MULTIPLE SERVERS USING THE SAME HYPERVISOR
         • THE MANAGEMENT CONSOLE CAN PROVIDES RESOURCES SUCH AS RAM, CPU, AND DISK
       • WHEN A TYPE 1 HYPERVISOR IS INSTALLED , THE SERVER IS REBOOTED ONLY INFORMATION IS DISPLAYED SUCH AS THE OS VERSION , RAM , IP
       • WHATS IS OVERALLOCATION ?
         • OVER ALLOCATION IS ASSIGNING MORE VIRTUAL MEMORY TO OS INSTANCES THAN THE SERVER’S PHYSICAL MEMORY, ASSUMING NOT ALL INSTANCES USE THEIR FULL MEMORY AT THE SAME TIME.
   • THE COMPLEXITY OS NETWORK VIRTUALIZATON
     • SERVER VIRTUALIZATION HIDES PHYSICAL SERVER RESOURCES FROM USERS. BECAUSE VMS CAN MOVE BETWEEN SERVERS, TRADITIONAL NETWORK CONFIGURATIONS BECOME COMPLEX TO MANAGE.
       • 1. VMS CAN MOVE BETWEEN PHYSICAL SERVERS, BUT TRADITIONAL NETWORKS ARE STATIC. BECAUSE OF THIS, ADMINISTRATORS MUST MANUALLY RECONFIGURE SWITCH PORTS AND VIRTUAL LAN (VLAN) SETTINGS TO MAINTAIN THE CORRECT NETWORK CONNECTIVITY.
       • 2 . ANOTHER PROBLEM IS THAT TRAFFIC FLOWS DIFFER SUBSTANTIALLY , FROM THE TRAFITTIONAL CLIENT-SERVER MODEL , TYPICALLY A DATA CENTER HAS A CONSIDERABLE AMOUNT OF TRAFFIC BEING EXCHANGED BETWEEN VIRTUAL SERVERS , THE SE FLOWS ARE CALLED EAST WEST TRAFFIC (LESTE-OESTE)
     • HOW DATA MOVES IN A DATA CENTER
       • EAST WEST TRAFFIC
         • EXCHANGED BETWEEN VIRTUAL SERVERS AND UCS SERVERS
           • CAN CHANGE IN LOCATION AND INTENSITY OVER TIME
       • NORT-SOUTH TRAFFIC
         • TRAFFICTYPICALLY IS DESTINED FOR OFF SITE LOCATIONS SUCH
           • ANOTHER DATACENTER
           • CLOUD PRIVDERS
           • INTERNET
         • TRAFFIC OCCURS BETWEEN DISTRIBUITION AND CORE LAYERS
   • THE NETWORK INFRAESRUCTURE CAN ALSO BENEFIT FROM VIRTUALIZATION
     • EACH NETWORK DEVICE CAN BE SEGMENTED INTO MULTIPLE VIRTUAL DEVICES OPERATE AS INDEPENDENT DEVICE SUCH
       • VIRTUAL INTERFACES
       • VIRTUAL LAN NETWORKS (VLANs)
       • VIRTUAL ROUTING AND FORWARDING (VRF)