Other Optional ISDN Configurations

Overview

Besides D channel backup and Information Elements, there are other optional configurations that are available with ISDN PRI.

This section outlines the configurations for:

B channel negotiation

ANI on demand

Vari-a-bill billing

B Channel Negotiation

ISDN cards support B channel negotiation on incoming calls as defined in Lucent TR41459 for both E1 and T1 cards. This feature allows the user receiving the incoming call (SETUP) to negotiate for the selection of the B channel. Only B channels controlled by the same D channel are considered for the selection procedure.

Call Flow

The SETUP message indicates the channel as either exclusive (does not accept an alternative) or preferred (any alternative is acceptable). If the channel is specified as preferred, but the user cannot grant the indicated channel, it selects any other B channel associated with the D channel. If the channel was specified as exclusive, no negotiation of the selection of the B channel is permitted and the call is rejected.

ISDN Interface Configure enables feature

B channel negotiation is enabled using the ISDN Interface Configure message. The following selection modes are provided:

Linear Clockwise (default)

Linear Counter-Clockwise

Circular Clockwise

Circular Counter-Clockwise

For NFAS, B channels on the same facility are selected before channels on other facilities.

Sample usage of feature

The following example shows the use of the ISDN interface Configure message to select the B channel negotiation mode.

X->H FE [00 0F] [00 60] 00 00 01 00 01 0D 03 00 00 17 06 00 01]

Byte

Field Description

Value and Indication

0

Frame

0xFE

1, 2

Length

0x000F (15)

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

Address Data Length

0x03

12, 13

Address Data[0] Logical Span

0x0000 (Span 0)

14

Address Data[1] Channel

0x17 (Channel 23)

15

Entity

0x06 (B Channel Selection Mode)

16

Data[0] Reserved

0x00

17

Data[1]

0x01 (Linear Clockwise)

18

Checksum

0xCS (not shown in trace)

ANI on Demand

ISDN cards support the Automatic Number Identification (ANI) on Demand feature as specified in Lucent TR41459. This feature allows the host to request the Calling Party Number from networks that support ANI such as AT&T MultiQuest.

A PPL Event Request message of ANI on Demand (0x21) must be sent from the host immediately after receiving the Request For Service message from the CSP. If the call has already been answered, a NACK of 0xC0 is returned by the CSP.

If successful, a FACILITY message is sent to the network requesting the ANI. A PPL Event Indication message of FACILITY ACKNOWLEDGE is returned containing the ANI information in a Calling Party IE or Network-specific Facility IE. If the ANI is not supported by the network or is not available, a PPL Event Indication message of FACILITY REJECT is returned by the CSP.

See the Lucent TR41459 specification for detailed information.

ANI on Demand Call flow

The figure below shows a call flow using the PPL Event Request message to implement the ANI On Demand feature.

Vari-A-Bill Billing

ISDN cards support the Vari-A-Bill feature as specified in Lucent TR41459. This feature allows the host to request a change in billing for an incoming call. You can use this feature after a call has been answered and only if the SETUP message indicates that the network supports the flexible billing service.

Enabling Vari-a-Bill

To enable Vari-a-Bill, send a PPL Event Request message with a PPL Event of Vari-A-Bill (0x20), specifying the new billing information in a Vari-A-Bill Data ICB (0x12). The CSP sends a FACILITY message to the network requesting the billing change.

If the call is not in the answered state, then the feature is not supported and a NACK of 0xC0 is returned by the CSP. A PPL Event Indication of FACILITY is returned from the network indicating whether the billing change was successful. See the Lucent TR41459 specification for detailed information.

Call Flow

The following call flow shows the use of the PPL Event Request message to implement the Vari-A-Bill feature.

 

Example

The following example shows the PPL Event Request message to implement Vari-A-Bill billing and change the billing rate.

Trace X->H FE [00 1E] [00 44] 00 00 01 00 01 0D 03 00 00 00 [00 05] 00 20 01 02 10 0A 01 12 07 01 90 30 31 32 35 36

BYTE

Field Description

Value and Indication

0

Frame

0xFE

1, 2

Length

0x001E

3, 4

Message Type

0x0044

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

Address Data Length

0x03

12, 13

Address Data[0] Logical Span

0x0000 (Span 0)

14

Address Data[1] Channel

0x00 (Channel 0)

15, 16

PPL Component

0x0005 (L3P Call Reference)

17, 18

PPL Event

0x0020 (Vari-A-Bill)

19

ICB Count

0x01

20

ICB Type

0x02 (Data)

21

ICB Subtype

0x10 (Formatted IE)

22

ICB Data Length

0x0A

23

ICB Data[0]Number of IEs To Follow

0x01

24

ICB Data[1] IE Type

0x12 (Vari-a-bill Data)

25

ICB Data[2] IE Length

0x07

26

ICB Data[3] Invoke ID

0x01

27

ICB Data[4] Billing Type

0x90 (New Rate)

28

ICB Data[5] Billing Data (Hundreds)

0x30

29

ICB Data[6] Billing Data (Tens)

0x31

30

ICB Data[7] Billing Data (Ones)

0x32

31

ICB Data[8] Billing Data (Tenths)

0x35

32

ICB Data[9] Billing Data (Hundredths)

0x36

33

Checksum

0xCS (not shown in trace)