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Chapter 6

SS7 ISUP Configuration

6.1 Introduction to the ISUP Layer

6.2 The ISUP Configuration

6.3 Sample ISUP Configuration File

6.4 ISUP Configuration Parameters Reference

: 6.4.1 General Parameters
: 6.4.2 Service Access Point (SAP) Definition
: 6.4.3 Network Service Access Point (NSAP) Definition
: 6.4.4 Circuit Group Definitions

6.1 Introduction to the ISUP Layer

The SS7 ISDN User Part (ISUP) software provides the interface for applications to establish, maintain, and clear circuit switched connections via the SS7 network, in accordance with the CCITT Q.761-Q.764 and ANSI T1.113 (1988 and 1992) recommendations. The ISUP layer is also responsible for circuit [group] management, such as blocking, unblocking, and resetting of circuits and circuit groups.
The configurable objects represented by the ISUP layer are Circuits, User Service Access Points (User SAPs), Network Service Access Points (NSAPs), and Routes. In addition, the ISUP layer has a set of general configuration parameters which define the behavior of the ISUP layer as a whole.
Circuits are the physical bearer circuits controlled by the ISUP layer. Circuits are identified by both a circuit index and a circuit identification code (CIC). The circuit index is a number unique across all circuits configured on a particular TX board. This number has only local significance - it is used between the ISUP layer and the local call processing application to identify a particular circuit.
The CIC (usually called the "kick", or "kick code") is used between signaling points (i.e., the ISUP layer and the far exchange that terminates the other end of the circuit) to uniquely identify a particular circuit. The CIC must be configured at both ends of the circuit to identify the exact same bearer facility, for example, the same T1 span and timeslot. CICs need not be unique across circuits that terminate on different far exchanges.
Circuits are specified in the ISUP configuration file in groups. A group is one or more circuits with contiguous circuit indexes and contiguous CICs that terminate on the same far exchange and have common characteristics. A single circuit group will frequently be used to represent all the timeslots on a single T1 or E1 span, for example. When defining a circuit group, only the circuit index and CIC of the first circuit in the group, along with the number of circuits in the group, are specified. The ISUP layer derives the circuit index and CIC for subsequent circuits since they are considered to be contiguous. The starting circuit index and starting CIC for a group need not be the same value.
User SAPs define the interface between the ISUP layer and the user applications. Note: This release of the SS7 ISUP layer supports only a single user application; therefore only one user SAP should be configured.
The NSAP defines the interface between the ISUP layer and the MTP layer. It identifies the MTP network SAP to used by the ISUP layer, allowing multiple user parts (e.g., ISUP and SCCP) to share access to the MTP layer services. Figure 6 illustrates the concept of user SAPs and NSAPs. Figure 6. ISUP User SAPs and Network SAPs
Routes can be configured to allow the ISUP layer to select the circuit for an outgoing call based on the called party number. A route typically specifies a "routing prefix" such as the first three digits or first six digits of a directory number, to match against the called party number. Typically the application itself will perform circuit selection for outgoing calls, since it must perform any hardware setup and/or switching on the physical circuit. In this case, there is no need to configure any routes.

6.2 The ISUP Configuration

The SS7 ISUP software contains a utility program, isupcfg, which reads a text configuration file and downloads the specified configuration to the ISUP task on the TX board, typically as part of the download sequence.
The general format of the ISUP configuration file is as follows: <General Configuration Parameters> <User SAP definition> <SAP Parameters> END <NSAP definition> <NSAP Parameters> END <NSAP (n - 1) definition> <NSAP Parameters> END <Route 0 definition> <Route Parameters> END <Route (n - 1) definition> <Route Parameters> END <Circuit Group 1 definition> <Circuit Group Parameters> END <Circuit Group n definition> <Circuit Group Parameters> END

6.3 Sample ISUP Configuration File

The ISUP software contains sample configuration files for both ANSI and ITU-T configurations. These configurations may be used in conjunction with the MTP sample configuration files to test ISUP applications using two TX boards in a back-to-back arrangement (see Chapter 3). The following example shows the sample ANSI configuration file for one board. # General configuration parameters MAX_SAPS 2 MAX_NSAPS 2 MAX_CIRCUITS 96 MAX_GROUPS 5 !max number of circuit groups MAX_CALLREFS 96 !max number of active circuits MAX_ROUTES 10 !max number of routes OPC 1.1.1 !my point code CLLINAME NMSsfwB2.41 END # Service Access Point (SAP) USER_SAP 0 SWITCH_TYPE ANSI92 !switch type (ITU, ANSI88, ANSI92, ANSI95, ITUWHITE, ITUBLUE, Q767) MAX_LENGTH 20 !max length of a phone number END # Network Service Access Point (NSAP) NSAP 0 SWITCH_TYPE ANSI92 !switch type (ITU, ANSI88, ANSI92, ITUWHITE, ITUBLUE, Q767) END # Circuit Database CIRCUIT 1 !circuit number CIC 1 !Circuit identification code DPC 1.1.2 !DPC of far exchange SWITCH_TYPE ANSI92 !switch type (ITU, ANSI88, ANSI92, ITUWHITE, ITUBLUE, Q767) TRUNK 708 CIRCUIT_TYPE BOTHWAY !INCOMING, OUTGOING, or BOTHWAY CONTROL_TYPE ODD_EVEN !ALL, NONE, or ODD_EVEN NUM_CIRCUITS 24 !number of circuits in this group END # CIRCUIT 25 !circuit number CIC 25 !Circuit identification code DPC 1.1.2 !DPC of far exchange SWITCH_TYPE ANSI92 !switch type (ITU, ANSI88, ANSI92, ITUWHITE, ITUBLUE, Q767) TRUNK 847 CIRCUIT_TYPE BOTHWAY !INCOMING, OUTGOING, or BOTHWAY CONTROL_TYPE ODD_EVEN !ALL, NONE, or ODD_EVEN NUM_CIRCUITS 24 !number of circuits in this group END # END

6.4 ISUP Configuration Parameters Reference

There are five major sections of the ISUP configuration file - general parameters, user SAP definition, network SAP definition, routes, and circuits.

6.4.1 General Parameters

The general parameters control the overall operation of the ISUP layer process.
Note: All ISUP timer values are in seconds.

Parameter Name

Default

Range

Usage

MAX_SAPS

1

1

Defines the maximum number of user applications

MAX_NSAPS

1

1-255

Defines the maximum number of interfaces with the MTP 3 network layer

MAX_CIRCUITS

96

0-65535

The maximum number of circuits to be managed by the ISUP layer.

MAX_GROUPS

32

0-65535

The maximum number of circuit groups managed by the ISUP layer.

MAX_CALLREFS

16

0-65535

This is the maximum number of call references, and hence connections, that ISUP can keep track of simultaneously.

MAX_ROUTES

16

0-65535

The maximum number of routes

OPC

none

The Point Code of this node, specified as x.y.z (three bytes, decimal, separated by periods), as a hexadecimal value preceded by 0x (0x123), or as a decimal value.

PC_FORMAT

DEFAULT

DEFAULT [DFLT],
INTER-NATIONAL [INTL],
JNTT

Point Codes are interpreted/displayed as 24-bit "8.8.8" values.
Point Codes are interpreted/displayed as 14-bit "3.8.3" values.
Point codes are interpreted/displayed as 16-bit "<M-Code>.<S-Code>.<U-Code>" values with the U-code in the most significant 7 bits, the S-code in the next 4 bits, and the M-code in the least significant 5 bits.

CLLINAME

none

The Common Language Location Identifier (CLLI) name assigned to this node (exactly 11 ASCII characters)

T18_TIMER

12

0-65535

Time to wait for a response to a group blocking message sent

T19_TIMER

60

0-65535

Time to wait for a response to initial group blocking message sent

T20_TIMER

12

0-65535

Time to wait for a response to a group unblocking message sent

T21_TIMER

60

0-65535

Time to wait for a response to initial group unblocking message sent

T22_TIMER

12

0-65535

Time to wait for a response to a circuit group reset message sent

T23_TIMER

60

0-65535

Time to wait for a response to initial circuit group reset message sent

TGRES_TIMER

5

0-65535

Group reset timer

TFGR_TIMER

5

0-65535

ANSI first group received timer

TRACE_EVENT

OFF

ON | OFF

Enables event logging when on

TRACE_DATA

OFF

ON | OFF

Enables data tracing when on

TRACE_WARNING

OFF

ON | OFF

Enables logging of unexpected information element value warnings when on

TRACE_ERROR

OFF

ON | OFF

Enables logging of message encoding errors when on

IG_PASS_ALNG

F

T/F

If set to TRUE (T), messages are sent in pass along format

ITU_UCICS

F

T/F

Setting to TRUE (T) allows an ITU configuration to send UCIC messages. Otherwise, UCIC's are not sent.

EXT_ELMTS

F

T/F

Setting to TRUE (T) allows the sending and receiving of extended elements

RAW_MSGS

F

T/F

Setting to TRUE (T) allows the sending and receiving of raw messages

END

N/A

N/A

Marks the end of the general section

Parameter Name	Default	Range	Usage
`MAX_SAPS`	1	1	Defines the maximum number of user applications
`MAX_NSAPS`	1	1-255	Defines the maximum number of interfaces with the MTP 3 network layer
`MAX_CIRCUITS`	96	0-65535	The maximum number of circuits to be managed by the ISUP layer.
`MAX_GROUPS`	32	0-65535	The maximum number of circuit groups managed by the ISUP layer.
`MAX_CALLREFS`	16	0-65535	This is the maximum number of call references, and hence connections, that ISUP can keep track of simultaneously.
`MAX_ROUTES`	16	0-65535	The maximum number of routes
`OPC`	none		The Point Code of this node, specified as x.y.z (three bytes, decimal, separated by periods), as a hexadecimal value preceded by 0x (0x123), or as a decimal value.
`PC_FORMAT`	`DEFAULT`	`DEFAULT [DFLT],` `INTER-NATIONAL [INTL],` `JNTT`	Point Codes are interpreted/displayed as 24-bit "8.8.8" values. Point Codes are interpreted/displayed as 14-bit "3.8.3" values. Point codes are interpreted/displayed as 16-bit "<M-Code>.<S-Code>.<U-Code>" values with the U-code in the most significant 7 bits, the S-code in the next 4 bits, and the M-code in the least significant 5 bits.
`CLLINAME`	none		The Common Language Location Identifier (CLLI) name assigned to this node (exactly 11 ASCII characters)
`T18_TIMER`	12	0-65535	Time to wait for a response to a group blocking message sent
`T19_TIMER`	60	0-65535	Time to wait for a response to initial group blocking message sent
`T20_TIMER`	12	0-65535	Time to wait for a response to a group unblocking message sent
`T21_TIMER`	60	0-65535	Time to wait for a response to initial group unblocking message sent
`T22_TIMER`	12	0-65535	Time to wait for a response to a circuit group reset message sent
`T23_TIMER`	60	0-65535	Time to wait for a response to initial circuit group reset message sent
`TGRES_TIMER`	5	0-65535	Group reset timer
`TFGR_TIMER`	5	0-65535	ANSI first group received timer
`TRACE_EVENT`	`OFF`	`ON \| OFF`	Enables event logging when on
`TRACE_DATA`	`OFF`	`ON \| OFF`	Enables data tracing when on
`TRACE_WARNING`	`OFF`	`ON \| OFF`	Enables logging of unexpected information element value warnings when on
`TRACE_ERROR`	`OFF`	`ON \| OFF`	Enables logging of message encoding errors when on
`IG_PASS_ALNG`	F	T/F	If set to TRUE (T), messages are sent in pass along format
`ITU_UCICS`	F	T/F	Setting to `TRUE (T)` allows an ITU configuration to send UCIC messages. Otherwise, UCIC's are not sent.
`EXT_ELMTS`	F	T/F	Setting to TRUE (T) allows the sending and receiving of extended elements
`RAW_MSGS`	F	T/F	Setting to TRUE (T) allows the sending and receiving of raw messages
`END`	N/A	N/A	Marks the end of the general section

6.4.2 Service Access Point (SAP) Definition

The SAP definition defines the characteristics of the ISUP service presented to the user application(s). Note: This release of the ISUP layer software allows for configuration of only a single ISUP user SAP. Therefore, only one application may use the ISUP service at a time. Timer default values in parenthesis are ITU values. Parameter Name Default Range Usage USER_SAP none 0-MAX_SAPS SAP number SWITCH_TYPE ANSI92 ITU, ITUWHITE, ITUBLUE, Q767, ANSI88, ANSI92, ANSI95 The protocol variant employed for this application. Must match (one of) the switch type(s) defined in the NSAP definition section. MASK none N/A Routing mask for circuit selection by ISUP. Maximum of 20 ASCII characters where a 1 indicates the digit is significant for route matching and a 0 indicates the digit is ignored for route matching. (e.g. 1110000000 would cause ISUP to treat the first 3 digits of a called address as significant when route matching). MAX_USER2USER 20 0..0xff Sets the maximum length of User to User information in an IAM. T1_TIMER 12 (15) 0-65535 Time to wait for a response to a release message sent. T2_TIMER 0 0-65535 Time to wait for a resume message after a suspend message received. T5_TIMER 60 (300) 0-65535 Time to wait for a response to initial release message sent. T6_TIMER 30 0-65535 Time to wait for a resume message after a suspend (network) message received. T7_TIMER 25 0-65535 Time to wait for a response (e.g., ACM, ANS, CON) to the latest address message sent. T8_TIMER 12 0-65535 Time to wait for a continuity message after receiving IAM requiring continuity check. T9_TIMER 180 0-65535 Time to wait for answer of outgoing call after ACM message received. T16_TIMER 12 0-65535 Time to wait for a response to a reset message sent. T17_TIMER 12 (300) 0-65535 Time to wait for a response to initial reset message sent. T27_TIMER 240 0-65535 Time to wait for a continuity check request after ensuing continuity check failure indication is received. See the TCCR_TIMER field below. T31_TIMER 0 (disabled) 0-65535 Time to wait before reusing call reference after a connection is cleared. T33_TIMER 15 0-65535 Time to wait for a response to information request message sent. TEX_TIMER 0 (disabled) 0-65535 Time to wait before sending ANSI exit message TCRM_TIMER 4 0-65535 Time to wait for a response to a circuit reservation message sent. TCRA_TIMER 10 0-65535 Time to wait for an IAM message after circuit reservation acknowledgment message sent. TCCR_TIMER 20 (240) 0-65535 Time to wait for CCR after the first COT indicating failure. See the T27_TIMER field above. END N/A N/A Marks the end of the SAP section

Parameter Name	Default	Range	Usage
`USER_SAP`	none	0-`MAX_SAPS`	SAP number
`SWITCH_TYPE`	`ANSI92`	`ITU, ITUWHITE, ITUBLUE, Q767, ANSI88, ANSI92, ANSI95`	The protocol variant employed for this application. Must match (one of) the switch type(s) defined in the NSAP definition section.
`MASK`	none	N/A	Routing mask for circuit selection by ISUP. Maximum of 20 ASCII characters where a 1 indicates the digit is significant for route matching and a 0 indicates the digit is ignored for route matching. (e.g. 1110000000 would cause ISUP to treat the first 3 digits of a called address as significant when route matching).
`MAX_USER2USER`	20	0..0xff	Sets the maximum length of User to User information in an IAM.
`T1_TIMER`	12 (15)	0-65535	Time to wait for a response to a release message sent.
`T2_TIMER`	0	0-65535	Time to wait for a resume message after a suspend message received.
`T5_TIMER`	60 (300)	0-65535	Time to wait for a response to initial release message sent.
`T6_TIMER`	30	0-65535	Time to wait for a resume message after a suspend (network) message received.
`T7_TIMER`	25	0-65535	Time to wait for a response (e.g., ACM, ANS, CON) to the latest address message sent.
`T8_TIMER`	12	0-65535	Time to wait for a continuity message after receiving IAM requiring continuity check.
`T9_TIMER`	180	0-65535	Time to wait for answer of outgoing call after ACM message received.
`T16_TIMER`	12	0-65535	Time to wait for a response to a reset message sent.
`T17_TIMER`	12 (300)	0-65535	Time to wait for a response to initial reset message sent.
`T27_TIMER`	240	0-65535	Time to wait for a continuity check request after ensuing continuity check failure indication is received. See the `TCCR_TIMER` field below.
`T31_TIMER`	0 (disabled)	0-65535	Time to wait before reusing call reference after a connection is cleared.
`T33_TIMER`	15	0-65535	Time to wait for a response to information request message sent.
`TEX_TIMER`	0 (disabled)	0-65535	Time to wait before sending ANSI exit message
`TCRM_TIMER`	4	0-65535	Time to wait for a response to a circuit reservation message sent.
`TCRA_TIMER`	10	0-65535	Time to wait for an IAM message after circuit reservation acknowledgment message sent.
`TCCR_TIMER`	20 (240)	0-65535	Time to wait for CCR after the first COT indicating failure. See the `T27_TIMER` field above.
`END`	N/A	N/A	Marks the end of the SAP section

6.4.3 Network Service Access Point (NSAP) Definition

The NSAP definition defines the characteristics of the ISUP interface to the MTP 3 layer . Parameter Name Default Range Usage SWITCH_TYPE ANSI92 ITU, ITUWHITE, ITUBLUE, Q767, ANSI88, ANSI92, ANSI95 The protocol variant employed for this MTP interface. Must match (one of) the switch type(s) defined in the MTP 3 NSAP definition section. SSF NATIONAL NATIONAL, INTER-NATIONAL,0-3, RESERVED, SPARE The value used in the sub-service field (SSF) of the service information octet in outgoing ISUP messages on this MTP interface. MTP_SAP 0 0-255 MTP Service Access Point to bind ISUP to; Must match one of the NSAP numbers defined in the MTP configuration file; also must be unique among all user parts that use the MTP service (e.g., SCCP, TUP) END Marks the end of the NSAP section

Parameter Name	Default	Range	Usage
`SWITCH_TYPE`	`ANSI92`	`ITU, ITUWHITE, ITUBLUE, Q767, ANSI88, ANSI92, ANSI95`	The protocol variant employed for this MTP interface. Must match (one of) the switch type(s) defined in the MTP 3 NSAP definition section.
`SSF`	`NATIONAL`	`NATIONAL, INTER-NATIONAL,`0-3, `RESERVED, SPARE`	The value used in the sub-service field (SSF) of the service information octet in outgoing ISUP messages on this MTP interface.
`MTP_SAP`	0	0-255	MTP Service Access Point to bind ISUP to; Must match one of the NSAP numbers defined in the MTP configuration file; also must be unique among all user parts that use the MTP service (e.g., SCCP, TUP)
`END`			Marks the end of the NSAP section

6.4.4 Circuit Group Definitions

The circuit group definitions specify the characteristics of each of the circuit groups to be managed by the ISUP layer. This includes the circuit identification codes (CICs), destination point code (DPC) at the other end of the circuits, and circuit type (incoming, outgoing, or both). One entry is made for each circuit group. Note: Timer default values in parenthesis are ITU values. Parameter Name Default Range Usage CIRCUIT none 1-MAX_CIRCUITS The number of the first circuit in this group. Circuits in this group are numbered from this number to (this number + NUM_CIRCUITS - 1). This range must be unique for all circuits defined. This number is used by the application and the ISUP layer to identify circuits, but has no meaning to the far exchange. CIC 1 0-4095 The circuit identification code (CIC) of the first circuit in this group. Circuits in this group are assigned CICs from this number to (this number + (NUM_CIRCUITS-1)). This number range must agree with the CICs assigned to this circuit group at the far exchange. DPC none The destination point code that this circuit group connect to. CIRCUIT_TYPE INCOMING INCOMING, OUTGOING, BOTHWAY Direction of calls allowed on this circuit group CONTROL_TYPE NONE NONE, ALL, ODD_EVEN Dual seizure control. GROUP_CHARS 0 0 - 0xff This value, if non-zero, is placed in the Group Characteristics of the CVR message. SWITCH_TYPE ANSI92 ITU, ITUWHITE, ITUBLUE, Q767, ANSI88, ANSI92, ANSI95 The protocol variant employed for this application. Must match (one of) the switch type(s) defined in the NSAP definition section. NUM_CIRCUITS 1 1-4095 The number of circuits in this circuit group. T4_TIMER 0 0-65535 Time to wait for call modification complete message T12_TIMER 12 (15) 0-65535 Time to wait for response to blocking message. T13_TIMER 60 (300) 0-65535 Time to wait for a response to the initial blocking message sent. T14_TIMER 12 (15) 0-65535 Time to wait for a response to an unblocking message sent. T15_TIMER 60 (300) 0-65535 Time to wait for a response to the initial unblocking message sent. TVAL_TIMER 30 0-65535 ANSI circuit validation timer. TPAUSE_TIMER 2 0-65535 Time to wait after MTP Pause before resetting circuits. END Marks the end of this circuit group definition.

Parameter Name	Default	Range	Usage
`CIRCUIT`	none	1-`MAX_CIRCUITS`	The number of the first circuit in this group. Circuits in this group are numbered from this number to (this number + NUM_CIRCUITS - 1). This range must be unique for all circuits defined. This number is used by the application and the ISUP layer to identify circuits, but has no meaning to the far exchange.
`CIC`	1	0-4095	The circuit identification code (CIC) of the first circuit in this group. Circuits in this group are assigned CICs from this number to (this number + (`NUM_CIRCUITS`-1)). This number range must agree with the CICs assigned to this circuit group at the far exchange.
`DPC`	none		The destination point code that this circuit group connect to.
`CIRCUIT_TYPE`	`INCOMING`	`INCOMING, OUTGOING, BOTHWAY`	Direction of calls allowed on this circuit group
`CONTROL_TYPE`	`NONE`	`NONE, ALL, ODD_EVEN`	Dual seizure control.
`GROUP_CHARS`	0	0 - 0xff	This value, if non-zero, is placed in the Group Characteristics of the CVR message.
`SWITCH_TYPE`	`ANSI92`	`ITU, ITUWHITE, ITUBLUE, Q767, ANSI88, ANSI92,` `ANSI95`	The protocol variant employed for this application. Must match (one of) the switch type(s) defined in the NSAP definition section.
`NUM_CIRCUITS`	1	1-4095	The number of circuits in this circuit group.
`T4_TIMER`	0	0-65535	Time to wait for call modification complete message
`T12_TIMER`	12 (15)	0-65535	Time to wait for response to blocking message.
`T13_TIMER`	60 (300)	0-65535	Time to wait for a response to the initial blocking message sent.
`T14_TIMER`	12 (15)	0-65535	Time to wait for a response to an unblocking message sent.
`T15_TIMER`	60 (300)	0-65535	Time to wait for a response to the initial unblocking message sent.
`TVAL_TIMER`	30	0-65535	ANSI circuit validation timer.
`TPAUSE_TIMER`	2	0-65535	Time to wait after MTP Pause before resetting circuits.
`END`			Marks the end of this circuit group definition.

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