F5 - 3DNS Solutions

The 3DNS Controller is a F5 Networks product intended to perform wide-area load balacing and high availability of Internet applications and services. It is able to manage traffic for large sites across multiple data centers, and ensure that users are connected to the data center nearest them. It does this by selectively handing out a particular IP address in response to a DNS name record request.

The 3DNS Model
The best way to understand what the 3DNS controller does, and how it does it, is to imagine it in action. Let us say that you are a large corporation with a website -- call it buystuffonline.com -- that gets a lot of traffic from all over the world. Your corporation depends on people being able to make purchases via its website for its revenue -- so if that site goes down, or is even merely slow, you're losing money. A lot of money. So you build datacenters -- facilities where a copy of your website is hosted -- in several major cities around the world: Tokyo, LA, New York, and London, in hopes that one of these datacenters will be at least on the same continent as any given customer.

Then you need a way of making sure that even though all of your customers are going to the same domain name, they will always be routed to a datacenter that is functioning, and preferably one that is both geographically close to them and responding quickly. It helps if the load is fairly evenly distributed among datacenters as well.

This is where 3DNS comes in. You give 3DNS a list of the IP addresses of your website hosts, and state which datacenter that host is located in. You associate all of these hosts IPs with a single DNS record -- say, www.buystuffonline.com. Then, whenever your customer opens up a browser and points it at www.buystuffonline.com, a name record lookup is performed, and your 3DNS hands out the IP address of one of the hosts in the list associated with that FQDN.

You can instruct 3DNS to spread the load evenly among all datacenters, or to send a given percentage of requests to a particular datacenter depending on its ability to serve traffic. 3DNS can even do fancy things like dynamically determine which datacenter is performing the best and hand out that IP address more often than others.

Features

1. High Availability
2. Geographic Load Balancing
3. Integration with Other F5 Products

3DNS is designed to run either as an add-on software module on an existing BIG-IP system (of any hardware type), or independantly on the 520 and 540 server appliances.