Isdn Configuration Concept; Isdn Layering; Isdn Layering Model - Patton electronics SmartNode Series Software Configuration Manual

SmartWare Software Configuration Guide
IMPORTANT
ISDN Configuration Concept

ISDN Layering

ISDN consists of 3 layers. Each layer has its own parameters that need to be configured.
• Layer 1, often called the physical layer, is responsible to transport single bits between two systems. Layer 1
does not guarantee that a message can be transmitted without errors.
Parameters: Clock mode, line codes.
• Layer 2 allows a station to reliably send messages to another station using the D channel. Layer 2 imple-
ments flow control, error detection and correction (retransmission) as well as addressing mechanism to
direct messages to individual devices.
Parameters: point-to-point or point-to-multipoint mode, network/user side, permanent layer 2 enabled.
• Layer 3 does send and receive application level messages (i.e. call control). It cares for sending broadcast
messages and collecting the individual results of the attached devices. It also handles the assignment of the B
channels.
Parameters: network/user side, protocol (i.e. DSS1), maximum number of channels.
The layered model of ISDN is reflected in the configuration by the use of different modes for each layer. The
layers are connected by using encapsulations and bindings. The encapsulation defines what the next higher
layer protocol will be. On the topmost layer, the binding finally selects a logical interface to connect the
port to. For more information how to configure and setup the physical ports for ISDN, please see Chapter 17,
"BRI port configuration"
mation about Q.921 and Q.931 configuration are available in Chapter 19,
page 215.

ISDN Configuration Concept

Connector pin-out and short circuits—Some of the Smart-
Node ISDN BRI ports are configurable to operate as network or
terminal ports. The pin-out of the sockets is switched according to
this configuration. Wrong port configurations, wrong cabling or
wrong connections to neighboring equipment can lead to short
circuits in the BRI line powering. Refer to the HW installation
guide and the port configuration sections below to avoid miscon-
figurations.
Call Control
Layer 3 (Q.931)
Layer 2 (Q.921)
Layer 1
Phys. Port
Figure 34. ISDN layering model
on page 203 and Chapter 16,
Encapsulation: cc-
Bind: <call control interface>
Encapsulation: q931
Encapsulation: q921
"PRI port configuration"
"ISDN configuration"
18 • ISDN Overview
on page 189. Detailed infor-
on
214