Learning OpenStack Networking - Third Edition

Routing east-west traffic between instances

In the network world, east-west traffic is traditionally defined as server-to-server traffic. In Neutron, as it relates to distributed virtual routers, east-west traffic is traffic between instances in different networks owned by the same project. In Neutron's legacy routing model, traffic between different networks traverses a virtual router located on a centralized network node. With DVR, the same traffic avoids the network node and is routed directly between the compute nodes hosting the virtual machine instances.