Page History

...

This section will describe conceptually how distributed routing and network ACL's are achievable with use of openflow rules and with use of an additional bridge doing L3 routing between one or more L2 switches where each L2 switch represents a subnet/tier. Further sections builds on the concepts introduced in this section to elaborate the architecture and design on how CloudStack and OVS plug-in can orchestrate setting up VPC's with distributed routing and network ACL's. 

Here is an example VPC deployment with three tiers, with VM's spanning 3 hypervisor hosts as depicted in below diagram. In this example VPC VR is deployed on host 3. A logical router which is a OVS bridge is provisioned on the rest of the hosts (excluding the host running VPC VR) on which VPC spans. On the host on which VPC VR is running there is no logical router. Irrespective of weather a host has VM's belonging to a tier or not, a bridge is setup on each host for each tier on the all of the hosts on which VPC spans. For e.g. host 1, does not have any tier 2 VM's still a bridge is created and is in full-mesh topology with the bridges created for tier 2 on host 2 and 3. Each of the logical router on the host is connected with patch ports [3] to the bridges on the host corresponding to tiers of the VPC. This setup of logical router is done to emulate a VPC VR (which has nics connected to bridges corresponding to each tier). VPC VR still needed to be deployed for north-south traffic and for other network services, so can not be replaced with logical routers only.

...