CISCO IOS in a Nutshell

Dialer Interfaces (Dialer Profiles)

So far, we have applied all the DDR-specific configuration items directly to a physical interface. This method of configuring DDR is called “legacy DDR.” The problem with legacy DDR is that it forces an interface to use the same parameters for all connections, incoming or outgoing. In the previous example, we set up a dialer map that called two different destinations through the same interface; all the other configuration items for the two destinations were the same. With dialer profiles, we can move the DDR information into the virtual dialer interface, which allows us to create rotary groups, dialer pools, or maps to different DDR information on the same physical interface.

The configuration of a dialer interface is no different from any other interface configuration:

interface dialer 1
  ip address 10.10.1.5 255.255.255.0 
  encapsulation ppp
  dialer string 4105551212

Dialer interfaces can be applied to physical interfaces in two ways: via rotary groups or dialer pools.

Rotary Groups

Rotary groups allow a group of interfaces to act as one to make or receive calls. This grouping is accomplished by mapping a single virtual dialer interface to many physical interfaces. Rotary groups are useful when you have one router that needs to call several destinations at the same time. Using a rotary group lets you avoid the most important limitation of our previous configuration: only one of the remote sites could be connected at a time.

In this example, we create ...