3Com 10014299 manual Isdn Overview, Configure Isdn

15 CONFIGURING ISDN PROTOCOL

	This chapter contains information on the following topics:
	■	ISDN Overview
	■	Configure ISDN
	■ Display and Debug ISDN
	■	Typical Configuration Example
	■ Fault Diagnosis and Troubleshooting of ISDN
ISDN Overview	ISDN (Integrated Services Digital Network), developed from telephone integrated
	digital network (IDN), provides end-to-end digital connection, so as to support
	wide range of services (including voice and non-voice services).

ISDN provides the user with a group of standard multifunctional user-network interfaces. In ITU-T I.412 recommendations, two types of user-network interfaces are specified: Basic Rate Interface (BRI) and Primary Rate Interface (PRI). The bandwidth of BRI is 2B+D, and that of PRI is 30B+D or 23B+D. Here:

■ B channel is a user channel, used to transmit the voice, data and other user information with the transmission rate 64kbps.

■ D channel is a control channel and used to transmit the common channel signaling, controlling the calls on B channels of the same interface. The rate of D channel is 64kbit/s (PRI) or 16kbps (BRI).ITU-T Q.921, the data link layer protocol of D channel, defines the rules by which the information is exchanged between layer-2 entities on the user-network interface through D channel. Meanwhile, it supports the access of layer-3 entity. ITU-T Q.931, the network layer protocol of D channel, provides methods to establish, maintain and terminate the network connection between communication application entities.

Figure 55 Protocol stack of ISDN D channel

Layer 3 Q.931

QSIG

Layer 2

Q.921 LAPD

Layer 1

BRI

PRI

Configure ISDN	ISDN configuration includes:
	■	Configure ISDN signaling type
	■	Configure QSIG signaling parameters