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Network Side Euro-ISDN

Overview

The ISDN software module supports network side Euro-ISDN PRI variant. This allows CSPs to handle basic call control, interfacing with a user-side.

ETSI specification support

The following is supported as defined in the applicable ETSI specification:

• All procedures, messages, and message content defined as mandatory for network side functionality.

• All call states supported in Dialogic’s ISDN PRI user side implementation.

• All network side call setup and tear-down procedures.

• All mandatory, bidirectional (network-to-user and user-to-network), circuit mode connection control messages.

• All mandatory network-to-user messages.

• All information elements that are designated as mandatory for network-to-user side messages.

• All timer values.

• All network side error handling procedures.

Supported Q.931 Messages

The following Q.931 messages are supported:

Call establishment

• ALERTING

• CALL PROCEEDING

• CONNECT

• CONNECT ACKNOWLEDGE

• PROGRESS

• SETUP

• SETUP ACKNOWLEDGE

Call information phase messages

• USER INFORMATION

Call clearing messages

• DISCONNECT

• RELEASE

• RELEASE COMPLETE

Miscellaneous

• FACILITY

• INFORMATION

• NOTIFY

• STATUS

• STATUS ENQUIRY

Other

• REGISTER

Specification Compliance

The ISDN PRI network side implementation complies to the signals and signaling procedures described by the ETSI 300 102-1 and 300 102-2 specifications specific to network side, with the following exceptions:

Dialogic’s network side Euro-ISDN PRI implementation does not support the following:

• Call re-arrangement procedures (SUSPEND and RESUME) (ETSI 300 102-1 section 5.6)

• Message segmentation (ETSI 300 102-1 section 5)

• Sending the STATUS ENQUIRY message (ETSI 300 102-1 section 5.8.10)

• Sending the CONGESTION CONTROL message (ETSI 300 102-1 section 3.1.3)

• Sending the Keypad Facility Information Element

Configuration

The network side ISDN PRI configuration procedure is the same as for the user side except that you must configure the D Channel for Network Side using the ISDN Interface Configure 0x0060 message (see the API message formats in the API Reference).

Example Message

The following is an example of the ISDN Interface Configure message, which changes the Connection Type to network side Euro-ISDN.

Trace H->X FE 00 0F 00 60 00 00 01 00 01 0D 03 00 00 17 01 00 17

Byte | Description | Value and Indication
--- | --- | ---
0 | Frame | 0xFE
1, 2 | Length | 0x000F
3, 4 | Message Type | 0x0060
5 | Reserved | 0x00
6 | Sequence Number | 0x00
7 | Logical Node ID | 0x01
8 | AIB Address Method | 0x00 (Single Entity)
9 | Number of Address Elements | 0x01
10 | Address Element Type | 0x0D (Channel)
11 | Data Length | 0x03
12, 13 | Data[0,1] Logical Span ID | 0x0000 (Span 0)
14 | Data[2] Channel | 0x17 (Channel 23)
15 | Entity | 0x01 (Connection Type)
16, 17 | Data[0,1] Value | 0x0017 (Network Side Euro-ISDN)
18 | Checksum | 0xCS (not shown in trace)

Call Flows

D Channel Failure with Re-establishment of D Channel

The following figure shows a call flow for a D channel failure followed by the re-establishment of the D channel.

1. Upon receiving a Layer 2 DISCONNECT, or no response to a Layer 2 RR (T203 expiry), from the User Side indicating a
D channel failure, the CSP sends a PPL Event Indication message of Network Side D Channel Temporary Malfunction (0x04).

2. All non-active calls are released and the host is sent Channel Released messages for each channel.

3. If the D channel is re-established within the period of the T309 timer (90 s), all active calls are maintained and the host is sent a PPL Event Indication message of Network Side D Channel
Re-established (0x06.)

D Channel Failure with no D channel Re-establishment

The following figure shows a call flow for a D channel failure with no re-establishment of the D channel.

1. On receiving a Layer 2 DISCONNECT, or no response to a Layer 2 RR (T203 expiry), from the user side indicating a D channel failure, the CSP sends a PPL event of Network Side D Channel Temporary Malfunction (0x04).

2. All non-active calls are released and the host is sent Channel Released messages for each channel.

3. If the D channel is not re-established within the T309 period
(90 s), the host is sent a PPL Event Indication message of Network Side D Channel Down (0x05).

4. All active calls are released and a Channel Released message is sent to the host for each channel, followed by:

• A DS0 Status Change message of Out of Service for all channels.

See Integrated Services Digital Network.
European Telecommunications Standards Institute
Call signaling protocol for setup and termination of calls.
Data channel. One of two fundamental components of an ISDN interface, it provides a path (16Kbps for BRI, 64Kbps for PRI) for carrying control signals and call data in a packet-switched mode.
A group of data bits in a specific format, with a flag at each end to indicate the beginning and the end of the frame.
See Address Information Block.
The information in an AIB that follows the header, down to the data field. An AIB can have one or more Address Elements. AEs correspond to Span, Channel, and SS7 Link.
Range of channels provided by T1 or E1 transmission service. A physical span is a group of channels taking up a single physical wire. A logical span is a group of channels taking up less than a single logical wire, or carried over more than one physical wire.
See Programmable Protocol Language.
A condition that, when met, drives a state machine from one state to another. A condition that drives a Component out of its current state by invoking an associated primitive.
In PPL, a condition that, when met, drives a state machine (PPL Component) from one state to another, by invoking an associated Primitive. In PPL files, an Event is marked by an arrow and text.