BGP communities are one of the most powerful tools for traffic engineering in production networks. This guide covers well-known communities, custom tagging strategies, and how to implement policy routing without destabilizing your upstream relationships.
We walk through real configurations on Cisco and Juniper platforms, explain when to use additive vs non-additive communities, and share field-tested patterns for multi-homed environments.
Finally, we cover monitoring and validation: how to verify that your communities are being honored by peers, and what to do when they're silently dropped.