| A | B |
|---|
| ISDN | a set of communication protocols proposed by telephone companies to permit telephone networks to carry data, voice, and other source traffic |
| 128 kbps | ISDN access speeds up to |
| Remote node method | a lower-speed connection, user appears to be a local network node , connection typically through an access server |
| end-to-end digital network | ISDN is a set of standards that define an |
| PPP | ISDN's most common data link encapsulation |
| HDLC | ISDN's default data link encapsulation |
| Each ISDN interface allows | only a single encapsulation type |
| Terminal Equipment 1 (TE1) | Designates a device that is compatible with the ISDN network |
| Terminal Equipment 2 (TE2) | Designates a device that is not compatible with ISDN and requires a Terminal Adapter |
| Terminal Adapter (TA) | Converts standard electrical signals into the form used by ISDN so that non-ISDN devices can connect to the ISDN network |
| Network Termination Type 1 (NT1) | Connects 4-wire ISDN subscriber wiring (S/T) to the conventional 2-wire local loop facility (U) |
| Network Termination Type 2 (NT2) | Directs traffic to and from different subscriber devices and the NT1. The NT2 is an intelligent device that performs switching and concentrating |
| BRI (Basic Rate Interface ) | Two 64 kbps (bearer) B channels, and One 16 kbps (signaling data) D channel (for LAPD) |
| PRI (Primary Rate Interface ) | 23 (T1) or 30 (E1) B channels and One 64 kbps (signaling) D channel |
| ISDN Services | BRI and PRI |
| 3 channels 2B+D | BRI |
| T1/E1 | PRI |
| S/T interface | defines the interface between a TE1 and an NT, also used to define the TA-to-NT interface |
| S | References the points that connect into the NT2, or customer switching device. |
| S interface | It is the interface that enables calls between the various customer premises equipment. |
| T | references the outbound connection from the NT2 to the ISDN network. |
| R | defines the interface between a TE2 and the TA |
| R interface | References the point (connection) that is between a non-ISDN compatible device and a terminal adapter. |
| U interface | defines the 2-wire interface between the NT1 and the ISDN network owned by the phone company |
| Customer premises equipment (CPE) | Terminating equipment, such as terminals, telephones, and modems, supplied by the telephone company, installed at customer sites, and connected to the telephone company network. |
| Service Profile Identifier (SPID) | Number that some service providers use to define the services to which an ISDN device subscribes |
| Identify you to the switch at the central office (CO) | SPID |
| Central office (CO) | Local telephone company office to which all local loops in a given area connect and in which circuit switching of subscriber lines occurs |
| Dial-on-Demand Routing (DDR) | Technique whereby a Cisco router can automatically initiate and close a circuit-switched session as transmitting stations demand |
| During a DDR session the router | spoofs keepalives so that end stations treat the session as active |
| DDR permits routing over ISDN or telephone lines using | an external ISDN terminal adaptor or modem |
