CCNA Labs — Router/Switch Memories

Lab Scenario:

You are a network administrator tasked with understanding the different types of memory in Cisco devices and their roles. You need to identify the memory types, explain their functions, and demonstrate how to view their usage.

Lab Activities:

1. Identify Memory Types:

• RAM (Random Access Memory):
• Also known as DRAM (Dynamic RAM).
• Used for the running configuration, routing tables, ARP cache, and packet buffering.
• Volatile (data is lost when power is off).
• ROM (Read-Only Memory):
• Stores the bootstrap program (bootloader).
• Non-volatile (data is retained when power is off).
• NVRAM (Non-Volatile RAM):
• Stores the startup configuration.
• Non-volatile.
• Flash Memory:
• Stores the Cisco IOS software image.
• Non-volatile.

1. Typical Usage:

• RAM:
• Running the IOS and its processes.
• Holding the current configuration.
• Buffering packets in transit.
• ROM:
• Bootstrapping the device.
• Performing basic hardware diagnostics.
• NVRAM:
• Saving the configuration that is used when the device boots up.
• Flash Memory:
• Providing persistent storage for the IOS and other files.
• Allowing for IOS upgrades.

Demonstrate Memory Usage (Cisco IOS Commands):

• Show RAM:
• show processes memory (Displays memory utilization by processes)
• show memory summary (Displays overall memory usage)
• Show Flash:
• show flash: (Displays files and directories in flash memory)
• show flash all (Displays detailed information about flash memory)
• Show NVRAM:
• show startup-config (Displays the startup configuration stored in NVRAM)
• Show version:
• show version (Displays information about the IOS version, ROM version, and memory sizes)

Example IOS Commands and Output Interpretation:

Cisco CLI

Router#show processes memory
Processor Pool Total: 16384000 Used: 10795244 Free: 5588756
 I/O Pool Total: 4194304 Used: 2365260 Free: 1829044
Router#show memory summary
Head total free(b) free(%)
Processor 16384000 5588756 34
 I/O 4194304 1829044 43
Router#show flash:
Directory of flash:/
 2 -rwx 76 Mar 01 2000 00:00:10 vlan.dat
 3 -rwx 4326532 Mar 01 2000 00:01:12 c2960-lanbasek9-mz.122-55.SE12.bin
Router#show startup-config
! Current configuration : 155 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router
!
interface FastEthernet0/0
 no ip address
 shutdown
!
end
Router#show version
Cisco IOS Software, C2960 Software (C2960-LANBASEK9-M), Version 12.2(55)SE12, RELEASE SOFTWARE (fc1)
...
ROM: Bootstrap program is C2960 boot loader
...
16384K bytes of processor board System flash (Read/Write)

Lab Considerations:

• Use Cisco Packet Tracer or a similar simulator to practice these commands.
• Pay attention to the output of each command and relate it to the memory type being examined.
• Experiment with different configurations and observe how memory usage changes.
• Consider the impact of large routing tables, complex configurations, and high traffic loads on memory usage.
• Understand that different cisco devices will have varying amounts of memory.

This lab will help you gain a solid understanding of Cisco router and switch memory and its practical implications. Checkout more CCNA Labs at certexams.com.