Optional Information Elements

Overview

Excel 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)