You are here: CSP Developer’s Guide: Common Channel Signaling > 8 ISDN > ISDN D Channel Configuration

ISDN D Channel Configuration

Overview

This section describes the second step in the basic ISDN configuration sequence.

• Assigning D channels

• Configuring D Channel options

• Adding facilities (for NFAS)

Assigning D Channels

The D Channel Assign message allocates a D channel at the timeslot you specify. In order for this assignment to succeed, the network interface card on which the D channel is to reside must be in service. The physical span MUST be assigned. You must specify the slot number of the ISDN card, as well as the ISDN type (primary and secondary).

Important! The D Channel Assign message sets all B channel configuration parameters back to their defaults.

The CSP software selects the actual D channel resource. If the host attempts to assign a D channel to a card that already has 32 D channels assigned, the host receives a Response Status of "ISDN D Channel Exceeds Max" (0xA4). You must indicate another card for
D channel processing.

All subsequent references to the D channel timeslot use the Logical Span ID and channel specified in the message. The facility number of 0 (zero) is defaulted to the span with the D channel assignment. When assigning the secondary type, the host selects the facility number.

Requirements for Assigning a D Channel

The following are requirements for assigning D channels:

• Span must be assigned.

• Network interface card(s) must be present and operational.

• ISDN card must be operational and have available D channel(s).

• Span and channel must not be assigned to an ISDN D or B channel location. For most applications, the D channel resides on the 24th channel of the T1 span, and timeslot 16 over E1.

Example

The following is an example of the D Channel Assign message. The example assumes that the Logical Span ID 0 is assigned and that the ISDN card is in slot 4.

Trace H->X FE 00 0E 00 C4 00 00 01 00 01 15 04 04 00 00 17 00

Byte | Field Description | Value and indication
--- | --- | ---
0 | Frame | 0xFE
1, 2 | Length | 0x000E
3, 4 | Message Type | 0x00C4
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 Type | 0x15 (Primary D Channel)
11 | Data Length | 0x04
12 | Data[0] Slot # | 0x04
13, 14 | Data[1] Logical Span ID | 0x0000
15 | Data[3] Channel | 0x17 (Channel 23)
16 | Secondary D Channel Facility Number | 0x00
17 | Checksum | 0xCS (not shown in trace)

Configuring D channels

The ISDN Interface Configure message configures attributes required for ISDN connections to the public network. To configure the connection endpoint variant, determine the type of switch from which the D channel will originate. This requires consultation with the provider. The default switch type is the Lucent 4ESS.

Normally, you do not need to configure Layer 2 and Layer 3 timers and counters. However, if it is necessary to change these, refer to ITU-T Q.921 and Q.931 for details on what they do and represent.

The table below lists the ISDN interface entities and their defaults. Use the ISDN Interface Configure message to change the default configuration.

Option | Default
--- | ---
Connection Type | Lucent 4ESS
D Channel Physical Medium | 64 kbps
HDLC Bit Polarity | Normal
Network Side Layer 2 | User Side
B Channel Selection Mode | Linear Clockwise
Location | User
Layer 4 Channel Release Request on ISDN DISCONNECT | Disabled
Protocol Discriminator Value for Maintenance Messages | 3
B Channel Encoding for Transmission | Channel Number

Requirements for Configuring D Channel Options

The following are requirements for configuring D channel options:

• The D channel must be assigned.

• The D channel parameters will only be initiated when the transition from out-of-service to in-service occurs.

Reconfiguring D Channels

Follow the steps below to reconfigure a D channel:

1. Take the B Channels out of service with the Service State Configure (0x000A) message.

2. Take the D Channels out of service with the Service State Configure (0x000A) message.

3. De-assign the D Channel with the D Channel De-assign (0x00C5) message.

4. Reconfigure the D channel with the D Channel Assign (0x00C4) message.

5. Reconfigure general options to an ISDN interface with the ISDN Interface Configuration (0x0060) message.

6. Reconfigure B channel information with the B Channel Configure (0x00C8) message

7. Bring span(s), B Channels and D channel(s) back into service with the Service State Configure (0x000A) message.

L3 Default Settings per Connection Type

The table below lists the default L3 configuration values for all connection types currently supported.

Connection Type | Default Settings
--- | ---
Lucent 4ESS (0x01) Lucent 5ESS (0x02) | ISDN Terminal Configure | LAPD Entities | T200 = 1 s T203 = 15 s (D Backup) or 30 s N200 = 3 | N201 = 260 ACK Pending timer = 0.5 s k = 7 L2 Options = 0
Lucent 4ESS (0x01) Lucent 5ESS (0x02) | PPL Timers | L3 Call Control Component (0x08) | T303 = 4 s T305 = 4 s T308 = 4 s T310 = 25 s T313 = 4 s |
PPL Config Bytes | L3 Call Control Component (0x08) | #1 = True #2 = False #3 = False #4 = 0x03 | #5 = False #6 = False #7 = 1 (Number of setup resends) #10 = False
PPL Config Bytes | L3 Global Call Reference Component (0x09) | #1 = False #2 = 2 #3 = False #4 = False #5 = False | #6 = False #7 = False #8 = False #9 = False #10 = False
| Other |  | Restart Procedure initiated
DMS100/250 (0x03/0x04) | ISDN Terminal Configure | LAPD Entities | T200 = 1 s T203 = 30 s or 15 s (D Backup) N200 = 3 s | N201 = 260 ACK Pending timer = 0.5 s k = 7 L2 Options = 0
DMS100/250 (0x03/0x04) | PPL Timers | L3 Call Control Component (0x08) | T303 = 4 s T305 = 4 s T308 = 4 s T310 = 10 s | T313 = 4 s
PPL Config Bytes | L3 Call Control Component (0x08) | #1 = True #2 = False #3 = False #4 = 0x03 | #5 = False #6 = False #7 = 1 #10 = False
PPL Config Bytes | L3 Global Call Reference Component (0x09) | #1 = False #2 = 2 #3 = False #4 = False #5 = False | #6 = False #7 = False #8 = False #9 = False #10 = False
Other |  | Restart initiated
AUSTEL (0x05) AUSTEL Netside (0x15) | ISDN Terminal Configure | LAPD Entities | T200 = 1 s T203 = 10 s N200 = 3 s N201 = 260 | ACK Pending timer = 0.35 s k = 7 L2 Options = 0x02 (stop sending SABME after N200)
AUSTEL (0x05) AUSTEL Netside (0x15) | PPL Timers | L3 Call Control Component (0x08) | T304 = 15 s T305 = 30 s T308 = 4 s T313 = 4 s |
PPL Config Bytes | L3 Call Control Component (0x08) | #1 = True #2 = False #3 = False #4 = 0x03 | #5 = False #6 = False #10 =False
PPL Config Bytes | L3 Global Call Reference Component (0x09) | #1 = False #2 = 2 #3 = False #4 = False #5 = False | #6 = False #7 = False #8 = False #9 = False #10 = False
PPL Config Bytes | L3 D Channel Control Component (0x0A) | #1 = True |
B Channel Options |  | Network Specific = 0x01 (no NSF) Calling Number Type = 0x01 (unknown) Called Number Type = 0x01 (unknown)
PCM Encoding Format |  | a-law
Other |  | Restart procedure is not supported. The ISDN card automatically responds to a valid SETUP message with both a CALL PROCEEDING and an ALERTING message.
JATE (0x06) | ISDN Terminal Configure | LAPD Entities | T200 = 1 s T203 = 30 s N200 = 3 s N201 = 260 | ACK Pending timer = 0.5 s k = 7 L2 Options = 0
JATE (0x06) | PPL Timers | L3 Call Control Component (0x08) | T303 = 4 s T305 = 4 s T308 = 4 s T310 = 30 s T313 = 4 s |
PPL Timers | L3 Global Call Reference Component (0x09) | Timer 16: T316 = 120 s |
PPL Config Bytes | L3 Call Control Component (0x08) | #1 = True #2 = False #3 = False #4 = 0x03 | #5 = False #6 = False #7 = 1 #10 =False
PPL Config Bytes | L3 Global Call Reference Component (0x09) | #1 = False #2 = 2 #3 = False #4 = False #5 = False | #6 = False #7 = False #8 = False #9 = False #10 = False
PPL Config Bytes | L3 D Channel Control Component (0x0A) | #1 = False |
B Channel Options |  | Network Specific = 0x01 (no NSF) Calling Number Type = 0x01 (unknown) Called Number Type = 0x01 (unknown) Calling Number Plan = 0x01 (unknown) Called Number Plan = 0x01 (unknown)
PCM Encoding Format |  | a-law |
Other |  | Restart procedure is supported For an outgoing call, a 55-second timer is started after the ALERTING message is received. If the timer expires before a CONNECT message is received, the call is cleared (a DISCONNECT message is sent).
EURO (0x07) | ISDN Terminal Configure | LAPD Entities | T200 = 1 s T203 = 10 s N200 = 3 s N201 = 260 | ACK Pending timer = 300 ms k = 7 L2 Options = 0
EURO (0x07) | PPL Timers | L3 Call Control Component (0x08) | T301 = 180 s T302 = 15 s T303 = 4 s T304 = 15 s T305 = 30 s | T308 = 4 s T310 = 25 s T313 = 4 s T322 = 4 s
PPL Config Bytes | L3 Call Control Component (0x08) | #1 = True #2 = False #3 = False #4 = 0x03 #5 = False | #6 = False #7 = 1 #8 = False #9 = False #10 = False #11 = False #22 =3
PPL Config Bytes | L3 Global Call Reference Component (0x09) | #1 = False #2 = 2 #3 = False #4 = False #5 = False | #6 = False #7 = False #8 = False #9 = False #10 = False
PPL Config Bytes | L3 D Channel Control Component (0x0A) | #1 = False |
B Channel Options |  | Network Specific = 0x01 (no NSF) Calling Number Type = 0x01 (unknown) Called Number Type = 0x01 (unknown)
PCM Encoding Format |  | a-law |
Other |  | Restart procedure is not supported
NI2 User (0x09) | See NI2 Netside (0x19)
EURO NETSIDE (0x17) | ISDN Terminal Configure | LAPD Entities | T200 = 1 s T203 = 10 s N200 = 3 s N201 = 260 s | ACK Pending timer = 300 ms k = 7 L2 Options = 0
EURO NETSIDE (0x17) | PPL Timers | L3 Call Control Component (0x08) | T302 = 15 s T303 = 4 s T304 = 20 s | T305 = 30 s T308 = 4 s T310 = 25 s
PPL Config Bytes | L3 Call Control Component (0x08) | #1 = True #2 = False #3 = False #4 = 0x03 #5 = False | #6 = False #7 = 1 #8 = False #10 = False #11 = False
PPL Config Bytes | L3 Global Call Reference Component (0x09) | #1 = False #2 = 2 #3 = False #4 = False #5 = False | #6 = False #7 = False #8 = False #9 = False #10 = False
PPL Config Bytes | L3 D Channel Control Component (0x0A) | #1 = False #2 = True Enable T309 logic |
PPL Timers | L3 D Channel Control Component (0x0A) | T309 = 90 s |
PCM Encoding Format |  | a-law |
Other |  | Restart procedure is not supported.
NI2 User (0x09) NI2 Netside (0x19) | ISDN Terminal Configure | LAPD Entities | T200 = 1 s T203 = 15 sec or 30 sec (D backup) N200 = 3 N201 = 260 | ACK Pending timer = 0.5 s k = 7 L2 Options = 0x08 (Enable Frame Reject Response (FRMR) sending.)
NI2 User (0x09) NI2 Netside (0x19) | PPL Timers | L3 Call Control Component (0x08) | T301 = 5 m T303 = 4 s T304 = 15 s T305 = 4 s T308 = 4 s | T310 = 25 s T313 = 4 s T322 = 4 s
PPL Config Bytes | L3 Call Control Component (0x08) | #1 = True #2 = False #3 = False #4 = 0x03 | #5 = False #6 = False #10 =False #7 = 0x01 #8= 0x2C #22=0x03
PPL Timer | L3 Global Call Reference Component (0x09) | T316 = 2 m |
PPL Config Bytes | L3 Global Call Reference Component (0x09) | #1 = False #2 = 2 #3 = False #4 = False #5 = False | #6 = False #7 = False #8 = False #9 = False #10 = False
PPL Config Bytes | L3 D Channel Control Component (0x0A) | #1 = False #2 = True |
PPL Timers | L3 D Channel Control Component (0x0A) | T321 = 40 s (user) T321 = 50 s (netside) T309 = 90 s |

Example Message

The following is an example of the ISDN Interface Configure message.

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

Byte | Field 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 | 0x0001 (Lucent 4ESS)
18 | Checksum | 0xCS (not shown in trace)

Adding Facilities

The D Channel Facility List Configure message adds or deletes facilities controlled by a D channel. For FAS arrangements, facility 0 is assumed for the span with the D channel. By sending the D Channel Facility List Configure message, NFAS is automatically assumed.

Important! NFAS is only supported over T1, not E1.

Specify the span and channel for D and assign the facility number
(1-19 for NI2 and 1-9 for other channel types) and the span ID for the facility being assigned. Each Primary D channel assumes it is located on facility 0. You can add up to 19 facilities with the D Channel Facility List Configure message.

The facility number is the span offset for the controlling D channel. For example, for NFAS the span on which the D channel is located is facility number 0. The next span controlled by that D channel is facility # 1, the next is facility # 2, and so on.

Requirements for Adding Facilities

The following are requirements for adding facilities to a D channel:

• D channel must be assigned (use the D Channel Assign message).

• Facility Number must be from 1-19 (0 is the D channel facility number).

• Facility must be assigned (use the Assign Logical Span ID message).

• Span and channel must not currently be assigned to an ISDN D or B channel location. For most applications, the D channel resides on the 24th channel of the T1 span.

Example

The following example shows the D Channel Facility List Configure message adding Logical Span ID #2, and assigning it to facility #1 for D channel 00,17.

Trace H->X FE [00 12] [00 C6] 00 04 01 00 02 0D 03 00 00 17 0C 02 00 02 01 01]

Byte | Field Description | Value and Indication
--- | --- | ---
0 | Frame | 0xFE
1, 2 | Length | 0x0012
3, 4 | Message Type | 0x00C6
5 | Reserved | 0x00
6 | Sequence Number | 0x04
7 | Logical Node ID | 0x01
8 | AIB Address Method | 0x00 (Single Entity)
9 | Number of Address Elements | 0x02
10 | Address Element 1 Address Type | 0x0D (Channel)
11 | Data Length | 0x03
12, 13 | Data[0,1] Logical Span ID | 0x0000
14 | Data[2] Channel | 0x17
15 | Address Element 2 Address Type | 0x0C (Span)
16 | Data Length | 0x02
17, 18 | Data[0,1] Logical Span ID | 0x0002
19 | Action | 0x01
20 | Facility Number | 0x01
21 | Checksum | 0xCS (not shown in trace)

See Integrated Services Digital Network.
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.
See Non Facility Associated Signaling.
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.
Digital communications link - voice, data, and video at a 1.544 Mbps rate (24 64 Kbps channels)
A digital communications link - voice, data, and video at a 2.048 Mbps rate; 30B/2D or 31B/1D (ISDN); non-North American version of T1.
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.
Protocol layer of the CSP.
International Telecommunications Union (UN)
Call signaling protocol for setup and termination of calls.
Bearer channel, 64Kbps (ISDN) The channel that carries the actual payload (as opposed to D-channels, which carry signaling data that helps route the payload).
Call processing layer of the CSP.
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.
Link Access Protocol (Procedure) – D channel (ISDN)
Positive acknowledgment to a message
See Programmable Protocol Language.
Setting up, monitoring, and tearing down calls.
See Pulse Code Modulation.
Japan Approvals Institute for Telecommunications Equipment
Frame Reject Response
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.