Is the routing table stored in NVRAM?

johnifanx98

or, it will be re-calculated each time a router reboot?

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Comments

drkat

The routing table is based off of the parameters in startup-config which is stored in NVRAM so technically yes??

azaghul

They will be recalculated each time, as there is no guarantee that dynamic routes learnt would stay the same.

Static routes would be reloaded with the startup-config, but would be only placed in the routing table depending on reachability. Thats my understand anyway.

boredgamelad

Routing and ARP tables are stored in RAM. They're rebuilt every time. As far as I'm aware, the only thing kept in NVRAM is the startup config.

drkat

His question was on reboot (or atleast how I took it) and RAM is cleared on power off

vishaw1986

Hey ,

We have two type of configuration
1>Running Configuration : This type of configuration is stored in RAM , which is of two type (Main Process Memory and Shared I/O Memory ). The main process memory include our Runn configuration , Routing table and Arp table . And this type of configuration is lost when router reboots .
2>Startup: Startup configuration is stored in NVRAM , which is our permanent memory and router restore the configuration when reboots .

Now Routing table :
When we are using dynamic routing like ( OSPF , EIGRP ) then when our router get reboot then each time the the routing table get re-calculated because we make neighbor ships in these case and when router get reboot the neighbor get down and re-calculation of routes get occur on every routes and our topology get changed . Same will happen when our router comes up .
But when we are using the static routes nothing will happen .

Hope this information helps you .

zrockstar

Vishaw's answer is correct. Just think of it like this, the routing table itself is stored in RAM, the commands used to populate the table (i.e. network statements, ip route statements) are store in the startup config which is stored in NVRAM (as long as copy run start has been issued).