1_Network Layer Router

1_Network Layer Router

1. Anatomy of a Router

   • A router is a computer
   • A Router is a computer
     • Router CPU and OS
   • Router Memory
     • Volatile Memory loses all of its content when the router is powered down or restarted!
       • Volatile Memory
         • RAM
           • Running IOS
           • Running configuration file
           • IP routing and ARP tables
           • Packet buffer
       • Non-Volatile
         • ROM
           • NVRAM
             • Flash
               • IOS
               • Other System Files
             • Startup configuration file
           • Bootup instructions
           • Basic diagnostic software
           • Limited IOS
   • Inside a Router
     • 1.Power Supply
       • 2. Shield for WIC
         • 3. Fan
           • 4. SDRAM
             • 5. NVRAM
               • 6. CPU
   • Back of a Router
   • Connecting to a Router
   • LAN and WAN Interfaces

2. Router Boot-up

   • Cisco IOS
     • The Cisco IOS is the OS of Cisco routers. Different IOS Versions provide different functions and services.
       • Storing IOS in flash allows the IOS to be upgraded to newer versions to add new features.
         • During bootup, the IOS is copied from flash memory into RAM
   • Bootset Files
   • Router Bootup Process
   • Show Versions Output

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