Update FAQ section with API and prefix limit details

Added Q&A about API support and prefix limits for voice service peering.

Author: cfields475

articles/internet-peering/walkthrough-communications-services-partner.md

@@ -252,3 +252,8 @@ Get answers to frequently asked questions.
 **Q.** Can we use APIs for onboarding?
 
 **A.** Currently, there's no API support. You can configure your service only by using the Azure portal.
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+**Q.** Setting the Prefix Limit: Recommended Max Prefix Limits for Voice service peering.
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+**A.** Microsoft generally announces up to 300 voice-enabled service IP prefixes on the internet, and this number may increase over time. To maintain stability and prevent session drops, it is recommended to set your Max Prefix Count to 500. This provides a safe buffer above current announcements and allows for future growth.
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