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> Call & Signaling Analysis
Overview
CDR provides comprehensive information on each and every call occurring on T1 and E1 lines, including,
- voice capture for both directions
- complete signaling information for each direction for CAS, ISDN, MFC-R2, SS7, and more
- all alarms and errors occurring during the call including BPV, Frame Errors, CRC errors, LOS, and more
- detailed voiceband event information occurring during the call including dual tones (DTMF, MF, MFC-R2), fax tones, modem signals, and more
- detailed analysis of the voiceband call including noise level, speech level, speech activity factor, echo measurements, and more
- categorization of the call as voice, fax, modem, or data
Call Data Records application compiles the output of CCA (Call Capture and Analysis) application and (optionally) VBA (Voice Band Analyzer) application and generates the following 2 types of reports –
- Call Summary Report - This report contains a single summary line for each call, giving information such as the inbound and outbound ports, channel number, time of seizure and release, and other summary information.
- Call Detail Report - This report contains call summary data, as well as the progression of supervisory and in-band events during the call and an overall summary of in-band measures for each direction.
GL Communications Inc’s approach to Call Data Records (CDR) compilation is as depicted in the pictures below.
- Call Capture & Analysis (CCA): This application captures bidirectional channel data and records it into PCM signal files. Capture may be triggered according to various protocols such as signaling bits, ISDN messaging, etc. CCA also records signaling and alarm events, as well as producing a summary record for each call. The files containing the event and call summary records are collectively referred to as Call Record Files.
Each CCA instance can monitor a single T1 or E1 trunk. Multiple CCA instances may be run concurrently to monitor multiple trunks. Here, CCA is discussed mainly in the context of Call Data Records generation. The CCA allows to log capture events in CSV or binary files and to feed these results into Call Data Records (CDR) application to provide an overall summary of the call as well as the event-by-event account of each call.
- Voice Band Analyzer (VBA): This application operates in near-real-time, processing the signal files recorded by CCA. VBA may be configured to detect in-band events such as sporadic echo, digit tones, in-band impairments, and the like. It also produces summary measurements of the captured signals, including active speech levels, noise level, percent time active, DC offset and the like. VBA records its output into two files, the first containing overall channel measurements, and the second containing event records.
A single VBA instance will analyze any number of files. This is an optional component. Here, VBA is discussed mainly in the context of Call Data Records generation.
Like VBA, a single CDR instance will compile any number of files into Call Data Records.
Main Features
- CDR is a daemon process which keeps busily looking for files to process and continues till manually stopped
- Classifies the captured events from CCA into Call summary information (CSR), Channel supervision (CAS, ISDN, etc.), and Facility alarms results
- Classifies the captured events from VBA into In-band events (digits, echo, etc.) results and overall traffic signal measurements
- CDR can be configured to output its results to “comma-separated values” (“CSV”) files or direct CSV file for loading into a database or spreadsheet
Call Data Records Configuration
CDR processes file sets are described in the following table. Each set consists of up to five files, all of which pertain to an individual call. All files are in “CSV” (“Comma-Separated Values”) format, a widely used format in the Windows® world understood by popular data management applications such as Microsoft® Excel and Access. Each file set pertains to a single call. That is, for each call, a separate file set is required.
“*” stands for the set of file names
| File |
Designation |
Description |
Source |
| Call Summary |
“*_csr.csv” |
Call summary information (CSR) |
CCA |
| Supervision |
“*_sbf.csv” |
Channel supervision (CAS, ISDN, etc.) |
CCA |
| Alarms |
“*_fac.csv” |
Facility alarms |
CCA |
| In-band Statistics |
“*_vbs.csv” |
Overall traffic signal measurements |
VBA |
| In-band Events |
“*_vbe.csv” |
In-band events (digits, echo, etc.) |
VBA |
The configuration screen is organized into sections -
- Signaling System: supports ISDN, CAS, and SS7 signaling system used by CCA to delimit calls. The signaling protocol used determines the Call Summary data that will be reported, and factors into CDR’s evaluation of call status. Note that CCA and CDR must agree on the signaling protocol.
- Data Sources: specifies source files utilization and channel supervision protocol used. Includes Call Summary, Signaling, Facility Status, & Voiceband types of data source. Strictly speaking, only the Call Summary file is required. However, a meaningful call detail report requires, at a minimum, supervisory and alarm files as well.
- Source File Disposition: manages CDR files after report generation for a given completed call.
- Report To: allows specifying the details of CDR’s output. Users may opt to output into a text file or direct output to a CSV (“comma-separated values”) file. Files for successive calls may all be stored in a single folder or may be stored in subfolders subsidiary to a single folder. CCA, VBA, and CDR must all use the same folder/subfolder structure.
- Control Buttons: controls naming and saving configurations.
CDR Output Formats
CDR can be configured to output its results to text or Comma-Separated Values (“CSV”) files.
Text Output
The CDR output in text format provides call summary report and call detail reports. Different sections of the Call Detail Report are -
- Call Summary - gives an overall summary of the call, including the ports and timeslot involved, the seize and release times, call duration, originator, and a release code.
- Call Events - gives an event-by-event account of the call. Events include channel supervision events, sporadic echo, alarms, ISDN calls, & others.
- In-band Summary - display depends on the Display Fields configurations for each algorithm in the VBA.
A Sample Call Detail Record shown for the In-band summary includes Active Speech Level algorithm (ASL, AF, RMS, Noise, and Clip fields) and Traffic Classifier algorithm (%Fax, %Voice, %Digits, %Quiet, and %Idle fields).
Screen Shot of call detail record in text file
Screen Shot of call summary record in text file
CSV Output
The CDR output in CSV format provides 3 different files for call summary, call events, and In-band summary. The name of the call summary records file will be the name you specified on the configuration screen followed by “_s.csv”, where the “_s” indicates summary records or “_e.csv”, where “_e” indicates event or “_v.csv”, where the “_v” indicates voiceband events.
Screen Shot of voice-band call (“_v.csv”,) detail record in csv file
Screen Shot of call summary (“_s.csv”,) record in csv file
Screen Shot of call event (“_e.csv”) record in csv file
Screen Shot of Full Duplex Audio View of a Captured Call in CCA
Buyer's Guide:
Please Note: The XX in the Item No. refers to the hardware platform, listed at the bottom of the Buyer's Guide, which the software will be running on. Therefore, XX can either be HDT, HDE, HUT, HUE, UTA or UEA depending upon the hardware.
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