Isdn Protocol Stacks; Isdn Application Scenarios - HPE FlexNetwork MSR series Configuration Manual

ISDN protocol stacks

ISDN provides dial-on-demand links. It sets up and maintains a link only when traffic is present.
The B-channels and the D-channel use separate protocol stacks, as shown in
Table 4 ISDN protocol stacks and OSI reference model
OSI model
Network layer
Data link layer
Physical layer
The following describes the functionality of the protocols in the D-channel protocol stack:
•
Q.921—Provides the following functions:
A reliable transport for Layer 3 Q.931 signaling messages.

Identification of frames.

Flow control mechanisms for data transmission and reception.

•
Q.931—Provides call control and management. These functions include call setup, call
disconnection, and request for services from Layer 2.
•
Call control (CC)—Forwards messages received by Q.931 from the network side to
higher-layer applications such as the DDR or voice module for information conversion and call
routing.
Figure 35 ISDN D-channel protocol stack

ISDN application scenarios

Figure 36 and
respectively.
Figure 36 Data ISDN application scenario
User
ISDN layer
Layer 3
Layer 2
Layer 1
Figure 37 show typical ISDN network diagrams for data services and voice services,
LAN
ISDN Router
D-channel
Q.931, Call Control (CC)
Q.921
I.430 BRI/I.431 PRI
ISDN network
E1 E1
ISDN Router
105
Table 4.
B-channel
IP, IPX
PPP, HDLC
I.430 BRI/I.431 PRI
Internet