---
title: Glossary · Cloudflare Magic Transit docs
description: Review the definitions for terms used across Cloudflare's Magic
  Transit documentation.
lastUpdated: 2024-08-13T19:56:56.000Z
chatbotDeprioritize: false
source_url:
  html: https://developers.cloudflare.com/magic-transit/glossary/
  md: https://developers.cloudflare.com/magic-transit/glossary/index.md
---

Review the definitions for terms used across Cloudflare's Magic Transit documentation.

| Term | Definition |
| - | - |
| letter of agency | Sometimes referred to as a Letter of Authorization. A document that authorizes Cloudflare to advertise your prefixes. This is required so transit providers can accept the routes Cloudflare advertises on your behalf. |
| policy-based routing | Policy-based routing (PBR) is a technique used to make routing decisions based on policies set by your administrador. |
| prefix | A number that identifies the network portion of an IP address. It tells devices if an IP address is on the same network or not. It is shown as a number after a slash (for example, `/31`) at the end of the IP address.Using an analogy, the prefix is like a street address. If an IP is in the same street, it belongs to the same network of devices. |
