usually configuration is not affected in the process. unless new IOS doe snot support come of the existing features and therefore those lines will disappear.
either way, I am afraid you would to reload the routes so it loads the new image. if it is 1st time in production, I suggest you test the IOS and make sure it does what it says on the tin.
What do u need to upgrade?
1-IOS image
2-tftp server to store image.
3-you also need to set router to boot from new IOS, then OLD one if storage allows ( in case you need to rollback).
4-make sure router can reach tfp server and path to image is correct.
main command is copy tftp flash, or copy tftp bootflash depending on platform and image location in router.
This task is relatively very simple, however it requires preparation and heavy testing.
http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00801347e2.shtml
Pls rate all helpful posts.
Sam
