We’re in discussions with an enterprise customer preparing for a major Data Center Consolidation. They are planning to lab test several misison critical applications to understand if application availability and transaction response times will meet performance goals after their West Coast Data Center (USA) is consolidated into an existing facility in the Southeast (SE). They’re concerned about the impact of increased WAN latency to some offices, especially on applications using Microsoft File Sharing and SQL Server. They’re also concerned about the application impact due to the increased traffic into the SE Data Center.
Their existing lab environment includes HP LoadRunner to generate user traffic. They are now considering the purchase of a WAN Emulation appliance to simulate the new transmission behavior of offices accessing applications in the relocated Data Center. This diagram provides a quick look at the star topology being emulated.
One major requirement they are struggling with is the ability to lab test the impact of increased traffic on the single (redundant) pipe into the SE Data Center. They’re looking at a lower cost network delay box that has an “East to West” hardware design and can support independent Network Profiles for each remote office, e.g. 110ms latency on a T3 from Seattle to SE Data Center, 70 ms on a T1 from Phoenix to the SE Data Center, etc. The problem is the 100 Mbps pipe into the SE Data Center that all remote offices share – the cheaper Network Emulator can’t model the shared pipe into the Data Center in an integrated fashion.
This customer wants a network model in their lab that provides unique latency characteristics for each office + emulates traffic contention on the shared 100Mbps pipe into the Data Center + also provides an option to emulate additional background traffic on the shared 100Mbps pipe so they can do Network Capacity Planning. The cheaper box can only support the first of these requirements – is that good enough?
Has anyone done WAN emulation testing for a star topology similar to this? Did you setup the remote office links with independent profiles without emulating the shared pipe into the Data Center? How did your your results compare once you went live on your Production Network? Any thoughts or recommendations?
January 8th, 2009 at 5:01 pm
Great post. I will read your posts frequently. Added you to the RSS reader.
January 8th, 2009 at 10:28 pm
Shunra APM blog post Network Emulation Gotcha – does your Network Model match your network?:.. http://tinyurl.com/8umlkb