[MT] Time to withdraw prefixes (#18268)

* added note on time to withdraw and bgp

* refined text

* refined text

* refined text

Author: marciocloudflare

src/content/docs/magic-transit/how-to/advertise-prefixes.mdx

@@ -62,11 +62,15 @@ You can only delete a prefix with an **Unapproved** status. To delete prefixes w
 1. From the **IP Prefixes** tab, locate the prefix you want to modify and select **Delete**.
 2. Confirm your choice from the modal by selecting **Delete**.
 
+:::note
+Withdrawing a prefix should propagate across Cloudflare's global network almost instantly, with changes typically taking effect within a few minutes at most. However, Cloudflare has no control over how long ISPs take to refresh their routes. Keep this in mind when announcing or withdrawing a prefix from your account, and plan accordingly.
+:::
+
 ## Border Gateway Protocol (BGP) control for advertisements
 
-Use BGP to control the advertisement status of your prefix — advertised or withdrawn — from Cloudflare’s global network for on-demand deployment scenarios. BGP Control works by establishing BGP sessions to Cloudflare’s globally distributed Route Reflectors, which will initiate propagation of your prefix advertisement across Cloudflare's global network.
+Use BGP to control the advertisement status of your prefix — advertised or withdrawn — from Cloudflare's global network for on-demand deployment scenarios. BGP Control works by establishing BGP sessions to Cloudflare's globally distributed Route Reflectors, which will initiate propagation of your prefix advertisement across Cloudflare's global network.
 
-Prefixes can be advertised from Cloudflare’s network in a supported on-demand method such as BGP Control, or dynamically via the UI, API, or [Magic Network Monitoring](/magic-transit/magic-network-monitoring/). During the onboarding of your on-demand prefixes, please specify whether you want BGP-controlled advertisement or dynamic advertisement (via dashboard/API/Magic Network Monitoring).
+Prefixes can be advertised from Cloudflare's network in a supported on-demand method such as BGP Control, or dynamically via the UI, API, or [Magic Network Monitoring](/magic-transit/magic-network-monitoring/). During the onboarding of your on-demand prefixes, please specify whether you want BGP-controlled advertisement or dynamic advertisement (via dashboard/API/Magic Network Monitoring).
 
 ![BGP diagram for Magic Transit](~/assets/images/magic-transit/bgp-diagram.png)
 
@@ -78,9 +82,13 @@ To begin using BGP control, contact your account team with the following informa
 
 After receiving your information, Cloudflare will update firewall filters to establish the BGP session and provide you with the BGP endpoints to control your prefixes.
 
+:::note
+When you withdraw a prefix using BGP, you must ensure the prefix is withdrawn across all BGP sessions on all route reflectors. Otherwise, your prefix will not be withdrawn from Cloudflare's global network.
+:::
+
 ### Regional settings
 
-Magic Transit requires static routing to steer traffic from Cloudflare’s network over one of your configured tunnel off-ramps (GRE, IPsec or CNI). Currently, advertisement of routes for traffic engineering purposes is not supported. As a best practice to reduce last-hop latency, you should consider scoping your routes regionally. The default setting for static route regions is **All Regions**. Refer to [Configure static routes](/magic-transit/how-to/configure-static-routes/) for more information.
+Magic Transit requires static routing to steer traffic from Cloudflare's network over one of your configured tunnel off-ramps (GRE, IPsec or CNI). Currently, advertisement of routes for traffic engineering purposes is not supported. As a best practice to reduce last-hop latency, you should consider scoping your routes regionally. The default setting for static route regions is **All Regions**. Refer to [Configure static routes](/magic-transit/how-to/configure-static-routes/) for more information.
 
 ## Example router configurations