Different types of router memory
Different Types of Router Memory
Memory on any device is used for storage and storing initial configuration and cache information while internal transactions of data processing is taking place.
Cisco routers also contain different types of components related to memory which takes care of storage and caching. Below are the types of memory used:
- ROM
- NVRAM
- Flash RAM
- RAM
ROM: This is the Read Only Memory which is available on the motherboard of the Cisco router. This contains the initial Bootstrap program and also the POST (Power on Self-Test) instructions. These ROM components or chips can be upgraded or replaced if required.
NVRAM: Non-volatile Random Access Memory: the start-up configuration is stored in this memory component. When a router is booted the IOS (Internetwork Operating System) reads this memory and gets the configuration file.
This memory can be erased if required. The router’s running configuration can be copied to the NVRAM and this can retain the configuration even if the router was shut down or power down, thus avoiding reconfiguration of the router every time it is powered off.
Flash RAM: This memory can be erased and reprogrammed. It contains the IOS that will be running on the router which helps in upgrading the OS without any chips to be removed.
Different version of IOS can be stored on a Flash memory. This memory can retain the configuration in even of a restart or power down. This memory stores the IOS in a compressed form.
RAM: Random Access Memory, this is similar to the RAM used on your desktop computers. It is volatile in nature which means that it loses the stored information if it is restarted or powered down.
The running configuration of the router is stored or held in the RAM. RAM is very fast in nature thus the running configuration is held in it.
Any changes that are done in the configuration are stored in the RAM till it is saved to the NVRAM. The RAM stores the routing table, cache entries, IP packets buffer etc.
The ‘show version’ command will give you some details on the router memory.
Read more
- What is Trivial File Transfer Protocol
- Naming Convention of Cisco IOS Image Files
- Cisco Router Configuration Files
- How to backup IOS and configuration files to Trivial File Transfer Protocol (TFTP) Server