6.2 Dialer Profile
6.2.1 Logical and physical configurations
Dialer profiles separate the logical configuration from the interface that receives or makes calls. Profiles can define encapsulation, access control lists (ACLs), and minimum or maximum calls, and turn features on or off.

With dialer profiles, the logical and physical configurations are dynamically bound to each other on a per-call basis, allowing physical interfaces to dynamically take on different characteristics based on incoming or outgoing calls, as shown in Figure .

Dialer profiles help users design and deploy complex and scalable circuit-switched internetworks by implementing a new DDR model in both routers and access servers. Dialer profiles separate the logical portion of DDR-such as the network layer, encapsulation, and dialer parameters-from the physical interface that places or receives calls, as shown in Figure .

Dialer profiles address several dialup issues:

  • One configured interface per ISDN interface -- Before dialer profiles, all ISDN B channels inherited the physical interface configuration.
  • Dialer map complexity -- Before dialer profiles, one dialer map was required per dialer per protocol, making multiprotocol configurations very complex.
  • Limited dial backup -- When a BRI or PRI is used to back up an interface, all the B channels are down and the whole interface is idle. In addition, the one-to-one relationship between interfaces and backup interfaces does not scale well to a packet-switching environment, in which many virtual circuits might need to be backed up individually and floating static routes are not desirable.

Dialer profiles let you create different configurations for B channels on an ISDN PRI or BRI interface. Using dialer profiles, you can do the following:

  • You can configure B channels of an ISDN interface with different IP subnets or (Internetwork Packet Exchange (IPX) networks.
  • You can use different encapsulations of B channels of an ISDN interface. However, only PPP and High-Level Data Link Control (HDLC) encapsulation are currently supported.
  • You can set different DDR parameters for B channels of an ISDN interface.
  • You can eliminate the waste of ISDN B channels by letting ISDN BRI interfaces belong to multiple dialer pools.

The main difference between a rotary group and a dialer profile is that a physical interface participates in only one rotary group. With a dialer profile, a physical interface can belong to many different pools.