5.5 Static and Default Routing
5.5.5 Deactivating routing updates

Interfaces that are tagged as passive will not send routing updates. To prevent routing updates from establishing DDR connections on dialer interfaces that do not rely on dynamic routing information, configure DDR interfaces with the passive-interface command or use access lists as described earlier. Using either the passive-interface command or an access list prevents routing updates from triggering a call. However, if you want routing updates to be passed when the link is active, use an access list rather than the passive-interface command.

 
Lab Activity 
  Given a Central site Cisco-IOS router with ISDN BRI capability and a branch office site Cisco-IOS router with ISDN BRI capability, configure both routers so that you can place an ISDN call between your two company sites.