Friday, October 16, 2009

Important Considerations When Choosing a WAN Optimization Solution

WAN optimization technology is becoming more strategic to application delivery as IT organizations become more dependent on the WAN for delivery of applications and services to remote users. In initial trials many IT organizations deployed this technology to a few key locations to solve bandwidth or latency challenges. The main selection criteria were around the core features such as data compression and application response time improvements.

These days IT organizations realize that WAN Optimization is an integral part of an application delivery network and they realize that they need to look beyond the original selection criteria and consider how it fits in their network architecture when planning a network-wide deployment. Let’s take a look at some of the important considerations when choosing a solution for improving application delivery.

Early WAN Optimization solutions delivered applications over tunnels that obscured traffic from reporting and monitoring tools. These days IT organizations need a solution that is transparent to the network and doesn’t interfere with routing architectures and doesn’t interfere with services and security on the network.

Sunday, October 11, 2009

Does Your Application Performance Reporting Overcome WOC Distortion?

The first surprise you will get after you consolidate your branch office servers in the data center is that application performance over the WAN falls off and user productivity suffers. To fix this you deploy WAN Optimization Controllers (WOCs) so your applications go much faster and you recover bandwidth that was lost to redundant traffic. After the WOC’s are installed a strange thing happens to your performance reports. Application response appears to be instantaneous. It’s as if the distance between your data center and your branch office shrunk to nothing. We know that you can’t overcome the speed of light and there will always be some latency on WAN links. So what happened?

What happened is that the WOC distortion effect has come in to play. WOCs proxy TCP at each end and send acknowledgments immediately. As result performance monitoring systems lose visibility to the actual round-trip time. WOC distortion poses a challenge to getting accurate end-to-end performance analysis. To understand how your applications are performing you need to know the average response time between client and server, the Network round trip time to move data from one node to another as well as the server’s response time to a request and the data rate that was achieved.