Internal · Sales & Engineering

Telecom Visual Glossary

Every term, every layer, every device — from the fiber in the ground to the app on the phone. Use this as a reference when talking to prospects or building integrations.

1. The Complete Network — Top to Bottom

Customer Layer — What the end user sees

📱 Mobile Subscriber

A person with a SIM card and phone number. They make calls, send texts, use data. They see the MVNO's brand, not the carrier's.

💻 Internet Subscriber

A person or business with a broadband connection — fiber, WiFi, or fixed wireless. They see the ISP's brand.

🏢 Enterprise Customer

A company that buys connectivity in bulk — multiple SIMs for employees, multi-site MPLS, dedicated bandwidth. Needs its own admin portal.

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Uses apps, makes calls, browses web

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Service Layer — MVNO / Virtual Operator

MVNO

Mobile Virtual Network Operator

Sells mobile services under its own brand. Owns no physical network. Buys capacity from a carrier (MNO) and internet from an ISP. Examples: Google Fi, Lycamobile, TrAC (planned).

SIM Card

Subscriber Identity Module

A tiny chip in the phone containing ICCID (card ID), IMSI (network identity), and Ki/OPc (secret authentication keys). The MVNO issues SIMs; the carrier's network validates them.

MSISDN

Mobile Station International Subscriber Directory Number

The phone number. Assigned when the SIM is activated. What people dial to reach the subscriber.

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Buys mobile capacity ↓ from carrier | Buys internet transit ↓ from ISP

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Carrier (MNO) — Mobile Network

Spectrum License

Government-issued permission to use specific radio frequencies (e.g., 700MHz, 1800MHz, 2600MHz). Extremely expensive. This is what MVNOs don't have.

Core Network (EPC / 5GC)

Evolved Packet Core (4G) / 5G Core

The brain of the mobile network. Routes calls, manages subscriber sessions, connects to the internet. Contains MME, SGW, PGW (4G) or AMF, SMF, UPF (5G).

HSS / HLR

Home Subscriber Server / Home Location Register

Database of all SIM cards and their secret keys. When a phone connects to a tower, the HSS verifies the SIM is legitimate using the AKA protocol. The MVNO syncs Ki/OPc keys here.

AKA

Authentication and Key Agreement

The protocol that verifies a SIM card. Tower sends a challenge, SIM responds using its secret key (Ki). If the response matches what the HSS expects, the subscriber is authenticated. Happens in milliseconds, every time you connect.

ISP — Internet Network

Backbone

The high-capacity network connecting cities, data centers, and internet exchanges. Usually fiber rings with redundancy. TrAC's backbone spans multiple African countries.

RADIUS

Remote Authentication Dial-In User Service

The protocol that authenticates internet subscribers. When you connect to WiFi or broadband, RADIUS checks your username/password and assigns your bandwidth limit.

MPLS

Multiprotocol Label Switching

Technology for creating private networks over shared infrastructure. Enterprise customers (B.Connected) use MPLS to connect multiple offices securely — like a VPN but at the network layer.

CDR

Call Detail Record

A record of every call, text, or data session — who, when, how long, how much data. The carrier generates CDRs; the MVNO receives them to bill subscribers. ISPs use RADIUS accounting records (similar concept).

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Managed by OSS/BSS software (that's us)

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Device Layer — Physical Equipment

📡 BTS / eNodeB / gNodeB

Base Transceiver Station

The cell tower. Transmits and receives radio signals to/from phones. eNodeB = 4G tower, gNodeB = 5G tower. Owned by the carrier, not the MVNO or ISP.

🖧 Core Router

e.g., Juniper MX204, Cisco ASR9000

The backbone router. Handles millions of packets per second. Configured via NETCONF/YANG. Owned by the ISP.

🌐 Edge Router

e.g., Juniper SRX, Cisco ISR

Sits at the boundary between the ISP's network and the customer. Applies security policies, bandwidth limits, VLANs.

📶 WiFi AP

Access Point — e.g., Cambium, Ubiquiti, HFCL

Provides wireless internet access. In hotels, offices, public spaces. Managed via vendor cloud APIs (cnMaestro, UniFi Controller).

💡 OLT

Optical Line Terminal — e.g., Calix, DZS, STL

The fiber hub. Sits in the ISP's exchange and connects to hundreds of customer premises via fiber optic cables (FTTH). Each customer has an ONT at their end.

🏠 CPE / ONT

Customer Premises Equipment / Optical Network Terminal

The box at the customer's location. Could be a MikroTik router, a fiber ONT, or a wireless CPE. The ISP installs and manages it remotely.

📡 Microwave

e.g., Ceragon IP-20, RADWIN JET

Wireless backhaul between towers or buildings. Used where fiber isn't available. Point-to-point links carrying hundreds of Mbps over kilometers.

📶 Small Cell

e.g., Baicells Nova, Lekha 5G

Mini cell tower for indoor or dense urban coverage. Fills gaps where macro BTS towers can't reach — malls, stadiums, office buildings.

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Connected by

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Physical Layer — What's in the Ground and Air

💡 Backbone Fiber

Owned by: ISP or Carrier

High-capacity fiber connecting cities, data centers, and exchanges. TrAC's "protected rings" are redundant loops — if one path is cut, traffic reroutes. ISPs like TrAC own this; MVNOs do not.

💡 Last-Mile Fiber (FTTH)

Owned by: ISP

Fiber from the exchange to the customer's home/office. The ISP installs and owns this. Connected via OLT (exchange side) and ONT (customer side).

📡 Licensed Radio Spectrum

Owned by: Carrier (MNO)

Government-issued permission to use specific frequencies (700MHz, 1800MHz, 2600MHz). Extremely expensive — this is what makes a carrier a carrier. Regulators: RURA (Rwanda), FCC (US), TRAI (India). MVNOs and ISPs do not own spectrum.

📡 Unlicensed Spectrum (WiFi)

Used by: ISP, anyone

Free-to-use frequencies (2.4GHz, 5GHz, 6GHz). No license needed. WiFi APs, point-to-multipoint wireless ISPs (WISPs), and hotspots use this. Lower power, shorter range than licensed spectrum.

🏗 Tower / Mast

Owned by: Carrier or Tower Company

Physical steel structure holding BTS antennas. Can be owned by the carrier or leased from a tower company (e.g., American Tower, IHS Towers in Africa). MVNOs share the carrier's towers — they don't build their own.

🔌 Copper / Coax

Owned by: Legacy ISP / Telco

DSL over phone lines, cable internet over TV coax. Being replaced by fiber. Still common in rural areas. Owned by the incumbent telco (e.g., BSNL in India, AT&T in US).

2. Services vs Medium vs Spectrum

A common confusion: "mobile" does not mean "voice." Mobile means cellular — which carries data, voice, AND SMS over licensed radio spectrum.

Service	Medium	Spectrum License?	Who Provides
Internet over fiber	Fiber optic cable	No	ISP (e.g., TrAC)
Internet over WiFi	Unlicensed radio (2.4/5/6 GHz)	No	ISP (e.g., TrAC)
Internet over fixed wireless	Unlicensed or lightly licensed	Usually no	ISP / WISP
Mobile data	Licensed cellular (4G/5G)	Yes	Carrier or MVNO
Mobile voice (calls)	Licensed cellular (4G VoLTE / 5G)	Yes	Carrier or MVNO
SMS / text messages	Licensed cellular	Yes	Carrier or MVNO
VoIP (WhatsApp, Zoom)	Internet (any medium)	No	Runs over ISP or carrier data

Key distinction:

Mobile = cellular = data + voice + SMS — all three travel over the same licensed radio spectrum via BTS towers
An MVNO doesn't just sell voice — it sells the complete mobile bundle (data + voice + SMS) under its own brand
Modern MVNOs are primarily about mobile data — voice is becoming secondary as users shift to VoIP (WhatsApp, Telegram)
An ISP like TrAC can provide internet without spectrum — but to offer mobile services (data/voice/SMS over cellular), they need either a spectrum license (MNO) or a carrier agreement (MVNO)
VoIP calls over WiFi/fiber don't need spectrum — but those are the customer's apps (WhatsApp), not TrAC's service

3. How Data Flows — A Single Web Request

When a TrAC MVNO subscriber in Kigali opens a website:

Phone sends request over radio to nearest BTS tower (owned by MTN/Airtel)
BTS forwards to carrier's core network (EPC)
Core network routes to PGW (data gateway) which connects to the internet
Request travels over fiber backbone to TrAC's network (internet transit)
TrAC's core router (Juniper MX204) routes to the destination
Response comes back the same path
Carrier generates a CDR — "this subscriber used 2MB of data"
TrAC (as MVNO) receives the CDR and rates it against the subscriber's plan
At month end, TrAC generates an invoice

4. Protocol Glossary

🔓

NETCONF / YANG

Network Configuration Protocol / Yet Another Next Generation

The standard way to configure routers and switches programmatically. NETCONF is the transport (like HTTP), YANG is the data model (like JSON schema). Replaces SSH+CLI. Used by Juniper, Cisco, Nokia, Huawei. Our SIG-NET module speaks NETCONF.

🔑

RADIUS

Remote Authentication Dial-In User Service

Protocol for authenticating internet subscribers. ISP's RADIUS server checks credentials, assigns bandwidth, and logs session data (accounting). FreeRADIUS is the most common implementation. Our SIG-RAD module manages RADIUS profiles.

📡

Diameter / S6a

Next-generation AAA protocol

Like RADIUS but for mobile networks. The S6a interface connects the MME (mobility manager) to the HSS (subscriber database). This is how the network looks up a SIM card's authentication keys. Our platform syncs SIM data to the HSS via this interface.

📋

SNMP

Simple Network Management Protocol

Legacy protocol for monitoring and configuring network devices. Still widely used for OLTs, microwave links, and older equipment. Being replaced by NETCONF for configuration, but still essential for monitoring (interface counters, CPU, memory, alerts).

🌐

REST API

Representational State Transfer

Modern HTTP-based APIs used by newer device vendors. Cambium (cnMaestro), Ubiquiti (UniFi), MikroTik (RouterOS), Calix (Cloud) all expose REST APIs. Easier to integrate than NETCONF/SNMP. Most of our CPE adapters use REST.

💳

TMF Open APIs

TM Forum standardized interfaces

Industry-standard API specifications for telecom. TMF632 (Party Management), TMF620 (Product Catalog), TMF622 (Product Ordering), TMF678 (Customer Bill). Required by some regulators and enterprise customers. Our TMF module provides facade APIs that translate to our internal models.

5. Business Terms

💰

BSS

Business Support Systems

Software that handles the business side: customer management, billing, payments, rating, collections, support tickets. "Who is the customer, what did they use, how much do they owe?" Our sigcore/bss modules.

⚙

OSS

Operations Support Systems

Software that manages the network: device configuration, monitoring, provisioning, fault management. "What devices do we have, are they working, how do we configure them?" Our sigtel/oss modules.

🏢

Contention Ratio

How many subscribers share the same bandwidth. A 50:1 contention ratio means 50 customers share one pipe — if everyone uses it at once, everyone gets 1/50th. TrAC's "zero-contention" means each customer gets dedicated bandwidth — you always get what you pay for.

📦

White-Label

Selling your product under someone else's brand. TrAC's B.Carried service is white-label — a downstream ISP buys TrAC's infrastructure and resells it under their own name. Their customers never know TrAC exists. Same concept as store-brand groceries.

🔄

Interconnect / Peering

How different networks exchange traffic. BGP peering is free mutual exchange between equals. Transit is paid — you pay a larger network to carry your traffic to the rest of the internet. TrAC buys transit from "three different providers across three different geographies."

📊

ARPU

Average Revenue Per User

The key telecom metric. Monthly revenue divided by subscribers. Higher ARPU = more valuable customers. Enterprise ARPU is typically 10-50x consumer ARPU — which is why the enterprise MVNO feature matters.

Industry Primer → MVNO & AKA Deep Dive → Integration Guide →

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