Learning OpenStack Networking - Third Edition

Distributing router ports

Without proper precautions, distributing ports with the same IP and MAC addresses across multiple compute nodes presents major issues in the network. Imagine a physical topology that resembles the following diagram:

In most networks, an environment consisting of multiple routers with the same IP and MAC address connected to a switch would result in the switches learning and relearning the location of the MAC addresses across different switch ports. This behavior is often referred to as MAC flapping and results in network instability and unreliability.

Virtual switches can exhibit the same behavior regardless of ...