Foundry Networks: Load Balancing For The Masses

It's easy to talk about load balancing, but how many people have written a book about the topic? We caught up with Chandra Kopparapu, vice president and general manager of the service provider and multi-layer switching business unit at Foundry Networks, to talk a bit about load balancing and why it matters to enterprise networks. (Foundry's ServerIron switches compete with offerings from Cisco, F5 Networks and others in this space.)

Networking Pipeline: I trust as the author of a book about the subject, you have a few things to say about load balancing.

Chandra Kopparapu: Well, we didn't invent rocket science here. Load balancing has existed in the networking space for a long time. Routers do load balancing every day, and clustering has been around since the days of Tandem, IBM and DEC. What's new about load balancing is that it's being brought to commodity computing. Instead of building a supercompter for a million dollars, you take commodity computers worth tens of thousands, and make them work like a supercomputer.

Networking Pipeline: What are the benefits of load balancing for the midsize or smaller enterprise customer?

Kopparapu: It's about scalability, high availability, and it can also be a security gateway. You can view load balancers as a bridge between a network and a service. One one side it speaks networking protocols, on the other side it understands server applications and APIs. By occupying that confluence, a load balancer can bring along benefits besides simple scalability.If a server goes down, traffic can be automatically directed to another server " that's high availability. If you want to take a server down or apply a patch, in the real world if you don't have a load balancer you have to tell users the server's going down or do the administration at night. And a load balancer can be a security gateway, to stop the bad guys that a firewall doesn't. These are not trivial benefits to the people running server farms.

Networking Pipeline: How does a load balancer catch what a firewall doesn't?

Kopparapu: Most enterprises keep their Web servers inside the firewall, and end up having to punch a hole " typically through Port 80 " to let traffic in. Ultimately, that can become a gateway for the bad guys. A firewall cannot distinguish different types of traffic, while a load balancer can look deeper into the packet and even into transactions, to determine what is a good or bad connection.

Networking Pipeline: Isn't there a performance hit from using load balancers?

Kopparapu: Sure, there's always a performance hit " anyone who tells you they have a "wire speed" load balancer is selling you marketing hype. But while you can't offer wire speed on every port, you can offer high performance levels. We offer 4 to 8 Gbps throughput, and that's plenty. You have to ask if that satisfies your requirements, especially weighed against the costs of downtime or taking a hit when a server goes down.Related Articles