Technical Helpweb

Symptom:
The Dialogic® demo application, gc_basic_call_model can be run using Dialogic® signaling products. This demo can be run in a back-to-back configuration using a single signaling board, signaling between the signaling boards ports (LIUs). The gc_basic_call_model code provides examples of using Globalcall SS7 to both originate and terminate calls. SS7 ISUP messages generated by this demo include;

- Initial Address Messages (IAM)
- Answer Complete Messages (ACM)
- Release Messages (REL) and Release Complete Messages(RLC).

These ISUP messages can be reviewed by utilizing a signaling tap and a Dialogic® SS7HD (high density) card running in monitor mode. The configuration for the components is provided in this note.

Fix / Solution:
gc_basic_call_model.cfg - this file is included as gc_basic_call_model_cfg.txt in this note.  The entries in this file define the SS7 channels used for the call process in the gc_basic_call_model sample.  SS7 configuration is located in the "For SS7 protocols" section of the configuration.  An example of a working configuration is: 

 

dkB2T1            SS7                In       NONE                1234567        0
dkB1T1            SS7                Out      NONE                3456789        0

 

where dkB1T1 identifies the first signaling channel on a trunk connected to 1 LIU and dkB2T1 identifies the first signaling channel connected to the second LIU.  The value of "In" identifies the signaling  channel receiving calls and the value of "Out" identifies the signaling channel making calls.  The phone number value of "1234567" is the DNIS number used for the call.  The outbound ANI phone number is hardcoded in the sample.  The "Out" phone number value of "3456789" is not used.

gcss7.cfg - this file is included as gcss7.txt in this note.  The configuration file is large so the focus here will be limited to the most relevant lines.  

- First, "System.Configuration = "Card"" defines the presence of a signaling card allowing Dialogic® Configuration Manager (DCM) control.   
- Next, "Service.GCTLOAD_Path = "c:\septel"" and  "SeptelCard.ConfigDir = "c:\septel"" identify the location of the configuration files used by DCM to load the signaling environment.  
- Last, "CGrp 0 dkB1" and "CGrp 1 dkB2" define the circuit groups used to support the SS7-based calls.

system.txt - This file is used by the signaling system upon startup.  
- "LOCAL         0x4d            * global call ss7" is used to load global call ss7 for use with the board.
- "REDIRECT     0x23    0x20    * ISUP module" redirects ISUP traffic to the signaling card for processing.  
- "REDIRECT    0xdf    0xef    * LIU/MTP2 status messages -> s7_log" adds all MTP2 messages to the ss7 log file, which can be helpful during development
- "FORK_PROCESS    s7_log.exe -td -m0xef -o0xff1f -fss7.log" increases the log level for messages logged.

config.txt - This file is used to control the board and protocols run.  
- "SEPTELPCI_BOARD  0  0x0042  ss7.dc3 ISUP" identifies the board number, the driver ss7.dc3" to download, and the protocol level to run.  
- "LIU_CONFIG" lines identify the ports used for board 0 and the type, code, frame format and crc mode defined are for a T1 trunk. MTP_CONFIG, MTP_LINKSET, MTP_LINK and  MTP_ROUTE are used to fully configure each of the signaling links.  
-- MTP_CONFIG's options field controls the run time operations for MTP.  The options are represented by a 32 bit mask and is defined in the SS7HD programmers manual.
-- MTP_LINKSET configures the signaling linksets to the adjacent signaling point. Key points are the stream, which is the LIU with the signaling trunk attached and the timeslot, which is the signaling timeslot used for signaling.  
-- MTP_ROUTE is used to route signaling traffic between the destination point codes.  This is a key entry allowing the demo application to run back to back on a single signaling board. 
-- "ISUP_CFG_CCTGRP" entries are to define ISUP configuration of the trunks used. Base CIC is used to identify the starting CIC number on the trunk.  The cic_mask value is used to identify the signaling channel. Pay attention to the opc and dpc      values as they provide the linkage needed for signaling across the trunks.

Product List: 
- The config.txt presented is specific to the Dialogic® SPCI product family but could be be used to support the Dialogic® SS7HD product line by changing the driver loaded.
- Dialogic® Global Call SS7 is also used in this application. 

Glossary of Acronyms / Terms

ISUP - ISDN User Part - signaling messages generated for calls in the SS7 network
IAM - Initial Address Message - used to route calls to destination in SS7 network
ACM - Answer Complete Message - sent from destination to source when the call is accepted
REL - Release Message - sent from the party hanging up first in a call
RLC - Release Complete - sent when the last party in a call has hung up

Related Documentation
Dialogic® SS7 Boards - SS7HD Programmer’s Manual:
http://www.dialogic.com/support/helpweb/signaling/software2.htm