Enterasys Networks X-PeditionTM manual Configuring Encapsulation, Isdn Callback

Implementing Dial Services

Configuring Encapsulation

When a clear data link is established between two peers, traffic must be encapsulated and framed for transport across the Dialer media.

PPPis the encapsulation method of choice for Dialer Services because it supports multiple protocols and is used for synchronous or asynchronous connections. Also, PPP performs address negotiation and authentication and is interoperable with different vendors.

ISDN Callback

ISDN callback functionality, also known as dial-back, is a Dial on Demand application to handle ISDN call charge billing. The benefit of this feature is, if a caller contacts the XSR, the router will try to call back a pre-configured number, and in the process reverse the associated charge. A maximum of 32 caller numbers can be set per Dialer port.

ISDN callback is supported for PPP or Multilink PPP traffic and can be applied in a backup scenario if the retry number is set to 1.

Configured with the dialer caller <number> callback command, the functionality employs caller ID screening with ISDN callback to accept calls from a specified phone number. The XSR matches phone numbers starting with the last digit.

Typically the ISDN switch does not provide the complete calling number, only the local number (four to seven of the least significant digits).

Note: If the ISDN switch does not provide the calling number, callback will fail.

Callback can be configured in point-to-point or point-to-multipoint applications with one or multiple neighbors. A neighbor in this context is considered one hop away from the XSR.

Refer to “Configuring ISDN Callback” on page 10-12for configuration examples.

Figure 10-3on page 10-7illustrates how Interface Dialers interact with Map Classes, Dialer Pools, Serial interfaces and three corporate sites served by the XSR. The squares with darkened backgrounds are Dialer Profiles. Note how Serial interfaces 0 - 4 and Boston and Hollywood are served by two Dialer Profiles.

10-6 Configuring Dialer Services