OpenStack Guide

OpenStack Networking Deployment Use Cases
The AFM plug-in supports the following OpenStack use cases:
1. Single Flat Network — All VMs can talk to each other via the shared network and to external network through the
physical route. In the simplest use case, a single OpenStack Networking network exists. This is a "shared" network,
meaning it is visible to all tenants through the OpenStack Networking API. Tenant VMs have a single NIC, and
receive a fixed IP address from the subnet(s) associated with that network.
2. Multiple Flat Network — VMs share the same shared network and can talk to each other and to VMs in other
shared networks and to external networks through the physical router. This use case is very similar to the above
Single Flat Network use case, except that tenants see multiple shared networks via the OpenStack Networking API
and can choose which network (or networks) to plug into.
3. Mixed Flat and Private Network —All VMs can talk to each other through the shared network and to external
networks through the physical router. VMs in a Tenant-Private Network can talk to each other but not to other
Tenant-Private Networks or external. This use case is an extension of the above flat network use cases in which
tenants also optionally have access to private per-tenant networks. In addition to seeing one or more shared
networks via the OpenStack Networking API, tenants can create additional networks that are only visible to users
of that tenant. When creating VMs, those VMs can have NICs on any of the shared networks and/or any of the
private networks belonging to the tenant. This enables the creation of "multi-tier" topologies using VMs with
multiple NICs. It also supports a model where a VM acting as a gateway can provide services such as routing,
NAT, or load balancing.
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