Version Control on Routers

Figure 2: Architecture Used for Routers

As equipment such as routers are generally unable to have version control software such as CVS installed it is necessary to slightly modify the system to archive router configurations. This is achieved by downloading the configurations to a box that has CVS installed and then adding committing and deleting files in the repository from there. The download of files can be done either as changes are made or periodically depending on the frequency of changes, the number of administrators that change router configurations and personal preference.

In the case of a Cisco router the download of configuration files can be effected be either of the following two commands after enabling rsh access from the machine that you are downloading the files to.

rsh <router-name> sh run > <router-name>

rcp <router-name>:running-config <router-name>

This system relies on the router to provide concurrency control of access to the configuration which in the case of routers I have had experience with is essentially no concurrency mediation to speak of. The roll back and audit trail semantics are the same as for the original architecture though the granularity of this depends on the frequency of the download and commit cycle.