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Optional Information Elements

Overview

Dialogic provides a format to send and receive Information Elements (IEs) per D channel. The data is represented using Information Control Blocks (ICB) with the ICB subtype of "Formatted IEs" (see Information Control Blocks in the API Reference). This allows flexibility when sending a message that has different types of data to transport. Multiple Formatted IEs can be loaded in the data section of the ICB.

APIs support IEs

The following API messages support the Formatted IE ICB:

• Request For Service with Address Data

• Outseize Control

• PPL Event Indication

• LPPL Event Request

• Release with Data

• Channel Release Request

Information Elements

The IE data is defined by the IE type. You can load multiple Formatted IEs in the data section of the ICB. Formatting specific IEs makes it easier for host development code to parse and create messages to pass specific data. The Raw IE ICB subtype is formatted similarly, however, it consists of the exact IEs to be sent.The format of the Formatted IEs ICB is shown in the table below.

ICB Count | 0x01
ICB Type | 0x02 (Data)
ICB Subtype | 0x10 (Formatted IE)
ICB Data Length | User-defined
ICB Data[0] Number of IEs To Follow | User-defined
ICB Data[1] IE Type | User-defined
ICB Data[2] IE Length | User-defined
ICB Data[3] IE Data[0] | User-defined
ICB Data[4] IE Data[1] | User-defined
ICB Data[4] IE Data[2] | User-defined
ICB Data[4] IE DATA[3] | User-defined

Information Element Library

To implement overlay networks or proprietary applications, the IE library allows you to store commonly used IE data. The library loads specific ISDN messages during call processing to reduce host message traffic.

There is a separate IE library for each active D channel on the ISDN card. The IE library contains a maximum of 30 library entries, and each entry is a maximum of 30 bytes. Each IE library entry can hold multiple IEs including codeset 6 and 7 IEs. IEs can be any type.

IE Restrictions

The following restrictions apply to the contents of an IE library entry

• The IE lengths must coincide with total length of data to be stored.

• The total length of the entry must be 30 bytes or less.

• The length specified internally for the IEs must be consistent.

Configuration

Use PPL AF 70 in the L3P Call Reference component to insert an IE Library into an outgoing ISDN message. The first argument is the IE library entry number to insert in the ISDN message.

L3P Call Reference DSD - Page 1 shows page 1 of the L3P Call Reference State Machine modified to use AF 70 to insert the IE into the outgoing SETUP message to the network. The first argument is the IE Library entry number (3). in the ISDN Interface Configure message example.

Use the ISDN Query message to retrieve the contents of the IE library. The IE library is stored in battery backed RAM.

L3P Call Reference DSD - Page 1 shows page 1 of the L3P Call Reference State Machine (l3p_cc). In the modified insert, AF 70 has been added after AF 77, with Argument 1 indicating IE Number 3. This inserts the IE into the outgoing SETUP message to the network.

Figure 8-6 L3P Call Reference DSD - Page 1

Examples

The following example shows an ISDN Interface Configure message used to load an IE library entry. Use the ISDN Query message to retrieve the contents of the IE library.

Byte | Description | Value and Indication
--- | --- | ---
0 | Frame | 0xFE
1, 2 | Length | 0x0020 (32)
3, 4 | Message Type | 0x00B2
5 | Reserved | 0x00
6 | Sequence Number | 0xSN
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 | Address Data Length | 0x03
12, 13 | Address Data[0,1] Logical Span | 0x0001 (Span 1)
14 | Address Data[2] Channel | 0x17 (Channel 23)
15 | Entity | 0x0B (Load IE Library Entry)
16 | Data[0] Entry Number | 0x04
17 | Data[1] IE Type | 0x01 (Q.931 IE)
18 | Data[2] Total IE Length | 0x0E (14)
19 | Data[3] IE Data | 0x70 (Called Party Number IE)
20 | Data[4] IE Data | 0x0C (Length of Called Party)
21 | Data[5] IE Data | 0xA1 (National number, ISDN Numbering)
22 | Data[6] IE Data | 0x31 (Digit 1)
23 | Data[7] IE Data | 0x35 (Digit 5)
24 | Data[8] IE Data | 0x30 (Digit 0)
25 | Data[9] IE Data | 0x38 (Digit 8)
26 | Data[10] IE Data | 0x38 (Digit 8)
27 | Data[11] IE Data | 0x36 (Digit 6)
29 | Data[12] IE Data | 0x32 (Digit 2)
30 | Data[13] IE Data | 0x33 (Digit 3)
31 | Data[14] IE Data | 0x30 (Digit 0)
32 | Data[15] IE Data | 0x30 (Digit 0)
34 | Data[16] IE Data | 0x30 (Digit 0)
35 | Checksum | 0xCS (not shown in trace)

Name for the data fields within an ISDN Layer 3 message. See Integrated Services Digital Network.
ICB. A standardized block that allows control data to be inserted in a standard way into API messages.
See Information Control Block.
RFS. A Status Message indicating that some entity is requesting service from the Excel platform.
Outgoing call setup during real-time call processing on a specific channel.
See Programmable Protocol Language.
See Integrated Services Digital Network.
See Atomic Function.
The condition of a component at a given instant. The current "context" of a PPL object, such as Idle, Seizing, Answered. In PPL files, a State is represented by a circle.
Random Access Memory
A State Machine defines the events (functions) required to drive a channel from one state to another through a graphical interface tool. A State Machine is configured and managed using API Messages or the PPL Tool. Based on the occurrence of an Event, a State Machine drives each channel through its Protocol Tables. It creates one state from another, invoked by an event. Processing is complete when a "normal" state is reached. "Wait" and "Stable" are normal states.
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.
Call signaling protocol for setup and termination of calls.