BSS/OSS Academy
💰
Section 5.3

Mediation & CDR Processing

CDR collection, normalisation, correlation, enrichment — the data pipeline from network to billing and its revenue leakage risks.

What Mediation Does

Mediation is the data pipeline between the network and the billing system. Network elements generate raw usage records — Call Detail Records (CDRs), Event Detail Records (EDRs), IP Detail Records (IPDRs) — in vendor-specific formats. Mediation collects, validates, normalises, correlates, enriches, and delivers these records to the rating engine in a format billing can process. Without mediation, billing has no usage data to rate.

Mediation
The BSS/OSS function responsible for collecting raw network usage records (CDRs/EDRs) from multiple network elements and platforms, normalising them into a consistent format, enriching them with subscriber and service context, filtering duplicates and errors, and delivering rated or ratable records to the billing system. Mediation is the single integration point between network event data and commercial billing.

The Mediation Pipeline

Mediation is a multi-stage pipeline. Each stage addresses a specific data quality or transformation requirement. Skipping stages produces billing errors, revenue leakage, or customer disputes.

Mediation Pipeline Stages

1
Collection
Mediation Collectors

CDRs are collected from network elements (MSCs, GGSNs, PGWs, IMS nodes, SBCs, etc.) via protocols like FTP, SFTP, FTAM, or streaming interfaces. Each network element type produces records in its own format.

2
Parsing & Normalisation
Mediation Parser

Vendor-specific record formats (ASN.1, CSV, proprietary binary) are parsed and normalised into a common internal format. Field names, date formats, duration calculations, and unit conversions are standardised.

3
Validation & Filtering
Mediation Validation Engine

Records are validated against business rules: zero-duration calls filtered, test numbers excluded, duplicate records detected and removed, and records with missing mandatory fields (calling number, timestamp) are rejected to an error queue.

4
Correlation
Correlation Engine

Partial records from different network elements for the same session are correlated into a single billable event. A VoLTE call may produce records from the P-CSCF, S-CSCF, and IMS-AS — these must be merged into one CDR.

5
Enrichment
Mediation Enrichment / Reference Data

Records are enriched with subscriber context (MSISDN → account mapping), service type classification, and any reference data needed for rating (e.g., number plan lookups for destination classification, roaming partner identification).

6
Delivery
Mediation → Rating/Billing

Normalised, validated, correlated, and enriched records are delivered to the rating engine — either in batch files or via real-time streaming for OCS environments.

Why Mediation Matters for Revenue

Mediation is the most common point of revenue leakage in a telco. CDRs that are lost, duplicated, miscorrelated, or delivered late directly impact revenue. Industry estimates suggest that 1-3% of gross revenue can leak through mediation failures. For a $1B-revenue operator, that is $10-30M annually.

Common Mediation Failure Modes
Lost CDRs (collection failure or file corruption), duplicate CDRs (correlation failure producing double-charges), late CDRs (arriving after bill run — either lost revenue or out-of-cycle adjustments), enrichment errors (wrong subscriber mapping leading to charges on wrong account), and format mismatches after network upgrades (new CDR fields not parsed, causing record rejection).
TM Forum Alignment
Mediation maps to eTOM 1.1.1.8.2 (Mediate & Orchestrate Billing Events). While there is no dedicated TMF Open API for mediation, the function bridges TMF635 (Usage Management API) — which defines usage consumption records — and the network-side event sources. Mediation is typically a proprietary integration layer, though vendors increasingly expose TMF635-compliant interfaces.

Key Takeaways

  • Mediation is the data pipeline from network to billing — without it, usage charges cannot be calculated
  • Six pipeline stages: collection, parsing/normalisation, validation, correlation, enrichment, and delivery
  • Mediation is the most common point of revenue leakage — 1-3% of gross revenue can be lost through CDR processing failures
  • Network upgrades are a major risk: new CDR formats must be reflected in mediation parsers before go-live or records are rejected