In this article I describe about the back up configuration of Router for CCNA exam. Back up configuration of router is necessary to be taken after any changes in running configuration. If router shut down due to any reason the running configuration will be erased. Next time when you power on the same router the current configuration will not found. To overcome these issue we take the back up configuration of Router. Router is just like a computer with a different Operating system known as IOS.
The internal processing functions of router are very similar to a normal computer. We know the basic functions of the memory of computer like RAM, ROM, CPU etc. Similarly the internal component of router works for data packet processing in router. The configuration of router stored in the running configuration when we do any changes from CLI. We need to keep these configuration save in NVRAM so in future the same configuration can be used for router.
We may take the backup in router’s Flash memory or in startup-config file. This is good if you don’t have any other device in your network. If router is damage or defective and no recovery option then the backup can not be taken back. This practice is similer to our data on any computer device. We take the important files back up in another drive or computer. Some time we take the backup at multiple places. Similarly we take the back up configuration of a Router in a TFTP server. TFTP is a service which required to be configured once. Before going to learn about the back up configuration of Router lets see the types of memories and their function in a router.
RAM
RAM is an acronym that stands for Random Access Memory. RAM of a router works like RAM of a computer. RAM is a volatile memory so it needs power all time. Router loads the IOS and the configuration file in RAM when the router is power on or reboot. It store the data like routing table and running config files. Data transfer speed of RAM of router is very fast. The running configuration remain save in the RAM or router until the power is available. Later these settings can be copied to start up configuration for future use. RAM stores data in power on condition of router. All data in RAM erased automatically if router is power off. The size of RAM in router is generally in MB. The size may be 16 MB, 32 MB.
RAM of a router keep the running configuration file, routing table and other information related to the interfaces of the router. When we works on CLI of a router actually we are working in the RAM of router. To take the back up configuration of Router, We need to copy the running configuration into startup configuration to save the current settings of the router. The startup configuration saved in the NVRAM which can be used later after rebooting the router.
ROM
ROM is acronym that stands for Read Only Memory. Data on ROM is write once only. After writing the data on ROM router can read the data but can not change it. ROM stores the bootstrap of IOS which is responsible to boot the router. Bootstrap find the IOS image file and run the IOS in RAM of router. ROM keep the instructions for POST process when router is power ON. ROM is chip on motherboard and it is programmed once only. ROM is just like the BIOS system of the computer. The booting process starts from the ROM of the router. ROM is a non volatile memory which does not require any power all the time to keep save the information in it. We can not do any changes in the ROM of a router. The settings of ROM configured by the firm so it is generally known as a firmware. The another internal component of router is NVRAM which is very similar to the ROM.
NVRAM
NVRAM keep the startup configuration file which is a backup copy of the running configuration. For back up configuration of Router we need to copy the running configuration to the startup configuration. Every time when the router power on the settings of startup configuration loaded into the RAM of the router. NVRAM is also a non volatile memory similar to ROM. In switches NVRAM stores the information of VLANs. When we configure VLAN in a switch the VLAN configuration saved into the NVRAM memory of the switch.
NVRAM stands for Nonvolatile Random Access Memory. NVRAM is like RAM but it is non volatile memory. It means NVRAM stores the data after power of the router. NVRAM stores the startup config file. Startup config file contains the routing table and other configuration which was copied from a running config file. The difference between NVRAM and ROM is that the content of ROM can not be changed but the content of NVRAM is changeable. When router is power on it search the startup config file in NVRAM only.
Flash Memory
Flash memory is a kind of EEPROM. EEPROM stands for Electrically Erasable Programmable Read-Only Memory. The content of Flash memory can not be change like ROM. Flash memory stores the IOS image. The data of Flash memory remain unchanged when the router is reboot or power off. We can say the operating system of router IOS saved in the flash memory. Every time when a router is power on the IOS loaded into the RAM from the Flash memory. The IOS checks all the interface of router when loaded first time in the RAM. To know all the functions or internal component of router you can read the full article related to booting sequence here.
Back up configuration of router in Flash memory and startup configuration
Back up configuration of router can be taken by copy command in privilege mode. So first thing is that you must know the enable password or enable secret password. Without these passwords you can not enter into privilege mode. Below image showing how many options you have to take backup of running configuration. You can take back up configuration of router into flash, ftp, scp, startup-config and tftp server.
To take back up configurations of router into flash memory follow the below steps. At step 2 you can take the default name by pressing enter or give your selected name.
Similarly you can take the back up configurations of router into startup-config file. See the below commands for example
Baku up configurations of router to TFTP server
To take back up configurations of router in TFTP server you need a TFTP server in your network. I create the TFTP server in my packet tracer example as shown in below image.
The IP address of both devices are written on interfaces. Now we have to take backup of running configuration in TFTP server by running the following commands. You have to enter the tftp server IP address and back up file name only.
In above commands I put the address of host 10.1.1.2 and destination file name test-config and the back up configurations of router completes. In next article we see how to restore the back up configurations of router from TFTP server.
I hope you found this article helpful related to back up configuration of router. For any query or suggestion on this article you may contact us or drop a comment below. Your suggestions are always welcome by us.
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