When you're creating new Rackspace cloud resources it's important to understand what a region is and how to use them effectively.
A region is a collection of one or more data centers with a low latentcy, high bandwidth network interconnecting them. A region can be viewed as a "logical data center" and is designated by the nearest airport code (e.g. DFW, ORD, LON, HKG, SYD).
Note: Because First Generation and Next Generations servers have different architectures, they're not considered to be in the same region, even if they are in the same datacenter. For example, a First Generation Cloud Server and Next Generation Cloud Server that are both located in the DFW datacenter are not in the same region.
Whenever possible, consider locating your Rackspace infrastructure in the same region to receive the following benefits:
Geographic choice. You can provision resources closer to your end users or other applications, data centers, clouds, etc. This becomes increasingly important with hybrid on-premises to public cloud scenarios.
Network performance. All resources provisioned within a region have internal connectivity over a private, low latentcy, high bandwidth network. The physical distance between resources is small and improves the speed of network traffic and throughput.
Free bandwidth. All communication over the Rackspace Network (aka ServiceNet) within the same region is free.
The example explains how to avoid bandwidth charges for communication between resoruces in the same region.
Let's say you're going to set up a new Cloud Load Balancer that will service two Cloud Servers currently running in the Dallas region. When you create the new load balancer, choose the same region as your servers, in this Dallas (DFW) region. There will be no bandwidth charges for the communications between the servers and load balancers in this region. Note that if later added a Cloud Server running in the Chicago region to the load balancer in Dallas, normal bandwith charges would be incurred for traffic between the server in Chicago and the load balancer in Dallas.
The diagram below provides a visual representation this concept:
This concept applies to all Rackspace cloud infrastructure that allows you to select a region when you create the resource. In most cases, you should create your resources in the same region to keep the resource close to end-users and other infrasturcture, for increased network performance, and to receive free bandwidth.
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