CCNA Notes : cont..
41.
Internal memory components of a Cisco router:
1. ROM
(Read Only Memory); Memory containing micro-code for basic functions
to start and maintain the router. ROM is not typically used after
the IOS is loaded.
2. RAM/DRAM
: stores the running configuration, routing tables, and packet
buffers. Some routers, such as the 2500 series, run IOS from Flash,
not RAM.
3. NVRAM
(Non-Volatile Ram): Memory that does not lose information when power
is lost. Stores the system’s configuration file and the
configuration register. NVRAM uses a battery to maintain the data
when power is turned off.
4. Flash
Memory: Stores the compressed IOS (IOS stands for Cisco Internetwork
Operating System) image. Flash memory is either EEPROM or
PCMCIA card. Flash memory enables you to copy multiple versions of
IOS software. This allows you to load a new level of the operating
system in every router in your network and then, to upgrade the
whole network to that version at an appropriate time.
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