a) Big pipes b) ability to filter the noise from real traffic as far as possible (i.e. there is little point in taking in a big pipe of DDoS traffic and then j

a) Big pipes b) ability to filter the noise from real traffic as far as possible (i.e. there is little point in taking in a big pipe of DDoS traffic and then just proxying it to the thinner pipe to the real backend - but if you can identify bad traffic you can drop it and not pass it through). c) being a CDN helps as a side-effect (what the CDN serves doesn't load the backend services, what can be served from the CDN works for users even if the backend is slow or down)