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VoIP Training

VoIP training for wholesale carriers and NOC teams

A free, practical course in ten lessons — from wholesale basics and SIP to VOS3000 setup, route quality, fraud detection, troubleshooting and server security.

Start Lesson 1

Who this course is for

New NOC engineers, routing and rates staff, and anyone joining a wholesale voice business who wants a clear, practical foundation. Each lesson ends with key takeaways and a short quiz.

1

VoIP & wholesale carrier basics

The vocabulary of wholesale voice: carriers, termination and origination, A-Z offers, CLI/NCLI/CC routes and how per-minute billing works.

 2

SIP fundamentals: call flow, SDP, RTP, codecs and NAT

How a SIP call is set up and torn down, what SDP and RTP do, how G.711 and G.729 differ, and why NAT causes audio problems.

 3

VOS3000 overview & architecture

A mental model of a VOS3000 system: what the server, database, management client and web portals do, and the key objects you configure.

 4

VOS3000: accounts, mapping & routing gateways, prefixes and rate groups

A practical checklist for onboarding a customer and a vendor: rate group, account, mapping gateway, routing gateway, routing order and testing.

 5

Rates, billing, balance and CDRs

How wholesale prices become charges: rate decks, longest-prefix matching, billing increments, balances, CDRs and reconciliation.

 6

Route quality KPIs: ASR, ACD, PDD, NER, MOS, packet loss and jitter

Definitions, formulas and interpretation of the KPIs every NOC watches, and how to read them together.

 7

FAS, CLI manipulation and fraud detection

How false answering, caller-ID changes and fraudulent traffic show up in your network, and how to detect and contain them.

 8

Route testing methods: test calls, passive monitoring and recording review

The three ways to test routes, what each is good at, their limits, and a routine that combines them.

 9

Troubleshooting common VoIP issues

A step-by-step method for failed calls, missing audio and codec problems, with the SIP codes you will meet most.

 10

VoIP server security

Layered protection for a softswitch: firewall, whitelists, automatic blocking, access control, limits, updates, backups and monitoring.

All examples use invented names and documentation IP ranges. Want to put these skills into practice? See VoxInspector for live route monitoring and FAS detection, or read the VoxComms blog.