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Chapter 9

SS7 TCAP Configuration

9.1 Introduction to the TCAP Layer

9.2 The TCAP Configuration File

9.3 TCAP Configuration Reference

: 9.3.1 General Parameters Definition
: 9.3.2 User Service Access Point (SAP) Definitions

9.1 Introduction to the TCAP Layer

The SS7 TCAP layer adds transaction services onto the connectionless data transfer service provided by the SCCP layer. Transactions in the SS7 network are typically database queries/responses or requests to activate services in remote switching points.
The SS7 TCAP layer can be configured for either ANSI (see ANSI T1.114) or ITU-T (see Q.771 - Q.775) operation, on a per-application basis. Use of ITU-T TCAP on top of an ANSI MTP/SCCP stack is fully supported. Use of the TX Series TCAP layer requires use (and proper configuration of) the TX Series SCCP and MTP layers.
The TCAP layer configuration consists of general configuration parameters and TCAP User Service Access Points (SAPs). The general configuration parameters define the resource allocation for the TCAP layer: maximum number of user SAPs, maximum number of simultaneous dialogs, and maximum number of outstanding invokes.
User SAPs define the interface between a TCAP user application and the TCAP layer. One user SAP is defined for each application using the TCAP layer services. A user SAP is associated with a single subsystem number and protocol variant (ANSI-88, ANSI-92, ITU-88, or ITU-92). Each TCAP user SAP maps directly to a SCCP user SAP in the SCCP configuration file (see Chapter 7), although not all SCCP SAPs must be assigned to TCAP applications; some applications may access the SCCP layer directly.
The relationship between TCAP user SAPs and SCCP user SAPs is illustrated in Figure 11. Figure 11. TCAP Service Access Points

9.2 The TCAP Configuration File

The TCAP distribution software contains an application (tcapcfg) which reads a text configuration file and downloads it to the TCAP layer on the TX Series, typically as part of the TX Series boot sequence. A sample configuration file, TCAPcpn.cfg is included with the distribution software and is shown below. Note: Not all configurable parameters need be specified in the configuration file; most will default to reasonable values if not specified. # # Sample TCAP configuration file for the following configuration # # General: # 4 user APPs max # 200 max simultaneous dialogs # 200 max simultaneous invokes # all others general defaults # General Configuration Section TCAP_ALARM_LEVEL 1 # standard alarms MAX_TCAP_USERS 4 # Max TCAP user applications MAX_TCAP_DIALOGS 200 # Max TCAP simultaneous dialogs MAX_TCAP_INVOKES 200 # Max TCAP simultaneous invokes END # # User SAP configuration for 1st application # USER_SAP 0 # Sap number start at 0 SWITCH_TYPE ANSI92 # one of ITU92, ITU88, ANSI92, ANSI88 END # User application 0 # # User SAP configuration for 2nd application # USER_SAP 1 # Sap number start at 0 SWITCH_TYPE ANSI92 # one of ITU92, ITU88, ANSI92, ANSI88 END # User application 0 # # User SAP configuration for 3rd application # USER_SAP 2 # Sap number start at 0 SWITCH_TYPE ANSI92 # one of ITU92, ITU88, ANSI92, ANSI88 END # User application 0 # # User SAP configuration for 4th application # USER_SAP 3 # Sap number start at 0 SWITCH_TYPE ANSI92 # one of ITU92, ITU88, ANSI92, ANSI88 END # User application 0

9.3 TCAP Configuration Reference

The following details the configurable parameters for each configuration section.

9.3.1 General Parameters Definition

The general parameters configuration section defines the operational characteristics of the TCAP layer, mostly upper bounds for internal data structures (these determine the amount of memory used by the TCAP layer). It is the first section of the configuration file.

Field Name

Default

Range

Description

MAX_TCAP_USERS

4

1..512

Maximum number of user SAPs

MAX_TCAP_DIALOGS

256

1..32767

Maximum number of TCAP transactions that may be pending at any one time.

MAX_TCAP_INVOKES

256

1..32767

Maximum number of TCAP invoke operations that may be pending at any one time.

MIN_TID_LEN

1

1..4

Forces use of transaction IDs of at least the specified number of bytes when using ITU-T TCAP; Primarily for interoperability with certain networks which require use of 4-byte transaction IDs.

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.

TCAP_ALARM_LEVEL

1

0..3

The level of alarms to be generated by the TCAP layer:
0=none (not recommended),
1=service impacting events,
2=individual transaction impacting events
(encode/decode errors),
3=debugging level.

Field Name	Default	Range	Description
MAX_TCAP_USERS	4	1..512	Maximum number of user SAPs
MAX_TCAP_DIALOGS	256	1..32767	Maximum number of TCAP transactions that may be pending at any one time.
MAX_TCAP_INVOKES	256	1..32767	Maximum number of TCAP invoke operations that may be pending at any one time.
MIN_TID_LEN	1	1..4	Forces use of transaction IDs of at least the specified number of bytes when using ITU-T TCAP; Primarily for interoperability with certain networks which require use of 4-byte transaction IDs.
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.
TCAP_ALARM_LEVEL	1	0..3	The level of alarms to be generated by the TCAP layer: 0=none (not recommended), 1=service impacting events, 2=individual transaction impacting events (encode/decode errors), 3=debugging level.

9.3.2 User Service Access Point (SAP) Definitions

One user SAP is defined for each application/subsystem using the TCAP layer services. A user SAP is associated with a single subsystem number and switch type (ANSI88, ANSI92, ITU88, or ITU92). Field Name Default Range Description USER_SAP None 0..MAX_USERS - 1 Marks start of a User SAP definition; User SAP numbers start at 0 and are numbered sequentially up to MAX_USERS - 1 SWITCH_TYPE ANSI92 ITU88, ITU92, ANSI88, ANSI92 Protocol variant used on this SAP. TCAP_T1 60 secs 1..32767 Default invocation timer, in seconds (time to wait for response to invoke) TCAP_T2 60 secs 1..32767 Time to wait for reject of a non-invoke component, in seconds, before considering operational successful (where applicable). TCAP_SEQ_TIMER 60 secs 1.255 Duration to request SCCP to maintain SLS for when sequential delivery required. SCCP_SAP USER_SAP 0..32766 SCCP SAP ID (from SCCP config.) to map this TCAP SAP onto; by default, set to the same value as the TCAP SAP ID.

Field Name	Default	Range	Description
USER_SAP	None	0..MAX_USERS - 1	Marks start of a User SAP definition; User SAP numbers start at 0 and are numbered sequentially up to MAX_USERS - 1
SWITCH_TYPE	ANSI92	ITU88, ITU92, ANSI88, ANSI92	Protocol variant used on this SAP.
TCAP_T1	60 secs	1..32767	Default invocation timer, in seconds (time to wait for response to invoke)
TCAP_T2	60 secs	1..32767	Time to wait for reject of a non-invoke component, in seconds, before considering operational successful (where applicable).
TCAP_SEQ_TIMER	60 secs	1.255	Duration to request SCCP to maintain SLS for when sequential delivery required.
SCCP_SAP	USER_SAP	0..32766	SCCP SAP ID (from SCCP config.) to map this TCAP SAP onto; by default, set to the same value as the TCAP SAP ID.

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