# Messaging concepts, explained

- Canonical URL: https://www.broadnet.me/explained
- Language: en
- Last updated: 2026-10-21
- Publisher: BroadNet (https://www.broadnet.me)
- Markdown version of the page above, generated from the rendered page.

Topic hub

Each hub organises one concept: a plain definition, how it works step by step, the key terms with their own answer pages, the regulations that apply, and the guides to read next.

- [A2P SMS explained Application-to-person SMS: how business messages are routed, priced and regulated, and how they differ from P2P traffic. 8 key terms Explore the topic](https://www.broadnet.me/explained/a2p-sms)
- [Sender ID explained The 'from' identity on an SMS: sender types, country registration and how networks stop spoofed brand names. 11 key terms Explore the topic](https://www.broadnet.me/explained/sender-id)
- [OTP verification explained One-time passwords and number verification: channels, a secure flow, fallbacks and the fraud to defend against. 10 key terms Explore the topic](https://www.broadnet.me/explained/otp-verification)
- [SMPP explained The protocol behind high-volume A2P SMS: binds, submit_sm, windows, delivery receipts and versions. 9 key terms Explore the topic](https://www.broadnet.me/explained/smpp)
- [SMS firewall explained How operators inspect SMS traffic to stop grey routes, SIM boxes, smishing and spoofed senders — and recover A2P revenue. 9 key terms Explore the topic](https://www.broadnet.me/explained/sms-firewall)
- [WhatsApp Business API explained Meta's enterprise WhatsApp product: BSPs, approved templates, the 24-hour window and per-message pricing. 9 key terms Explore the topic](https://www.broadnet.me/explained/whatsapp-business-api)

[Browse all answers](https://www.broadnet.me/answers)