"We know, for example, that we haven't sent any DNS inquiries out from our network. We can therefore safely filter the responses from DNS resolvers. We can therefore drop the response packets at our routers or, in some cases, even upstream at one of our bandwidth providers. The result is that these types of attacks are relatively easily mitigated."

This seems to be a bit more specific and does indeed give insight on how to mitigate this type of attack.