Non-Volatile RAM (NVRAM)

Non-Volatile Random Access Memory (NVRAM) is used as the storage location for the router’s startup configuration file. After the router loads its IOS image, the settings found in the startup configuration are applied. When changes are made to a router’s running configuration, they should always be saved to the startup configuration (stored in NVRAM) or they will be lost when the router shuts down. Remember that the running configuration is stored in RAM, which is erased when the router is powered down. On a Cisco 2500 series router, NVRAM is a relatively tiny 32KB in size.

Figure: Cisco router memory elements and purposes. 

Author: Dan DiNicolo

Dan DiNicolo is a freelance author, consultant, trainer, and the managing editor of He is the author of the CCNA Study Guide found on this site, as well as many books including the PC Magazine titles Windows XP Security Solutions and Windows Vista Security Solutions. Click here to contact Dan.