(Page 1 of 1 in this chapter)

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 Series 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 3 digits or first 6 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 Series board, typically as part of the download sequence.



The general format of the ISUP configuration file is shown below.


<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 Series 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 MTP3 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




 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

 . 





 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).




 T1_TIMER



 12



 0..65535



 Time to wait for a response to a release message sent.




 T2_TIMER



 0 (disabled)



 0..65535



 Time to wait for a resume message after a suspend message received.




 T5_TIMER



 60



 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



 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 continuity check failure indication is received.




 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



 0..65535



 Time to wait for CCR after COT indicating failure




 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 MTP3 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 MTP3 NSAP definition section.




 SSF



 NATIONAL



 NATIONAL,


 INTER-NATIONAL



 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.


  





 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.




 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 (disabled)



 0..65535



 Time to wait for call modification complete message




 T12_TIMER



 12



 0..65535



 Time to wait for response to blocking message. 




 T13_TIMER



 60



 0..65535



 Time to wait for a response to the initial blocking message sent.




 T14_TIMER



 12



 0..65535



 Time to wait for a response to an unblocking message sent.




 T15_TIMER



 60



 0..65535



 Time to wait for a response to the initial unblocking message sent.




 TVAL_TIMER



 30



 0..65535



 ANSI circuit validation timer.




 END



 



 



 Marks the end of this circuit group definition.
























 
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