This chapter shows you how to configure and use the following network security features:
• 3-1: Modems: Cisco routers and access servers can use internal or external modems to place and receive calls. Both digital and analog modems can be used. This section presents information on how to configure and manage all types of modems.
• 3-2: ISDN: A router can provide dial-in or dial-out service over an ISDN PRI (23 or 30 channels) or an ISDN BRI (two channels).
• 3-3: Dial-on-Demand Routing (DDR): Calls can be placed dynamically from a router to a dialup destination based on specific traffic. DDR provides very flexibleand scalable support for multiple dialing interfaces used to reach a destination. Connections can be made ...