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http:\\ciscocertifications.info
Show Configuration
Same as "show running-config" under older versions of the IOS software
NVRAM
Non-Volatile RAM stores the routers startup-config file. NVRAM contents are retained when you
power down or reload.
Show Startup-Configuration
To view the contents
FLASH
Flash is an EPROM. Flash memory holds the operating system image (IOS). Having Flash allows you
to update software without removing or adding chips. Flash content is retained when you power down
or reload. Multiple copies of IOS can be stored in Flash memory.
show flash - To view the contents
ROM
ROM contains the power on diagnostics, a bootstrap program and operating system software. To per-
form upgrades the physical chips must be removed and replaced.
*Keypoints:Know what the purpose of each of the above "show" commands is.Know what the router stores in RAM.Know that the "show version" command will display system hardware configuration, softwareversion, and the sources of configuration files and boot images.CDP
Cisco Discovery Protocol is a proprietary protocol to allow you to access configuration information on
other routers and switches with a single command. It uses SNAP at the Data-Link Layer. By default
CDP sends out a broadcast every 60 seconds and it holds this information for 180 seconds. CDP is en-
abled by default.
CDP is enabled globally by entering global config mode and typing:
Router(config)# cdp run
CDP is disabled on a specific interface by entering the interface configuration mode and typing:
Router(config-if)# no cdp enable
At the Interface config mode you can only enable or disable CDP. At the global config mode you can
also set the holdtime and timer. For Example:
Router(config)# cdp timer 30Router(config)# cdp holdtime 120
When CDP is enabled you can view details of other Cisco devices by typing:
show cdp neighbors
This displays the following information about neighboring router's:
1)
router's hostname