Applying Scalability Patterns to Infrastructure Architecture gives a good overview of the different ways to scale your infrastructure.
Too often software design patterns are overlooked by network and application delivery network architects but these patterns are often equally applicable to addressing a broad range of architectural challenges in the application delivery tier of the data center.
It comes as a surprise to me that these (mostly classic) patterns should all originate in SW design school, but then again, what do you expect from a die hard infrastructure guy who never really went to SW design school?