Cisco has the functionality to do an in-place replacement of the running config, without requiring a device reload. This is similar to the rollback functionality seen on Juniper devices. This function automatically swaps the config, automatically adding/removing any differences encountered. This is different than just doing "copy start-config running-config" as that will merge the changes, and won't delete anything.
configure replace <filename>
ROUTER#$configure replace tftp://10.10.10.5/ROUTER-autoarchive-Jun--9-15:09:56.137-EDT-0 This will apply all necessary additions and deletions to replace the current running configuration with the contents of the specified configuration file, which is assumed to be a complete configuration, not a partial configuration. Enter Y if you are sure you want to proceed. ? [no]: y Loading ROUTER-autoarchive-Jun--9-15:09:56.137-EDT-0 from 10.10.10.5 (via Ethernet0): ! [OK - 7029 bytes] Total number of passes: 1 Rollback Done
You can also use this to roll back to the startup config:
configure replace nvram:startup-config
To make your router feel more like a Juniper, add this to your config:
alias exec rollback configure replace nvram:startup-config
Then you just need to type "rollback" to replace your running config with the startup config.