Let’s clear up the confusion before a sales rep gets their hands on you.
Prolexic is a DDoS mitigation service, specifically for layer 3/4 attacks. It scrubs traffic *before* it hits your origin. A CDN is a global network of servers that caches and delivers your web content (images, JS, HTML) to improve performance and handle some layer 7 traffic.
They are different tools for different jobs.
* Prolexic stops someone from flooding your pipe with garbage packets.
* A CDN makes your website load faster for a global audience and can handle some volumetric attacks as a side effect.
So, does it *replace* a CDN? No. Not unless your only goal is to survive a massive SYN flood and you don’t care if your site loads slowly for everyone, everywhere, all the time.
The real question you should be asking is whether Akamai will try to bundle them together (they will) and claim you need both (you might, but not from them). Their pricing model for these combined services is where the fun begins. You’ll pay for the CDN, then pay a premium for Prolexic on top, often with opaque thresholds for "surge" pricing during attacks.
If you already have a CDN, you can often get "good enough" DDoS protection from them or your cloud provider. Prolexic is for when you’re a giant target and need a dedicated, always-on shield. For a beginner? Probably overkill and a fast track to budget overruns.
Trust but verify.