CenturyLink resell Distributed Arbor scrubbing facilities
https://www.digitalmarketplace.service.gov.uk/g-cloud/services/968779429408654
Flowbased :
This technology looks at the header of the packet, which is summary data. Based upon this summary data it tries to make a decision on the integrity of the packet.
As traffic increases it effectively gets confused and has to send traffic to an (expensive) scrubbing centre for cleaning.
PACKET INSPECTION (TDD)
The Corero software inspects (detects and mitigates) at wire-speed. The software is able to inspect the full frame of the packet.
It also generates block filters that only match the bad traffic for a range of other DDoS attacks. In these cases the good traffic still goes through (no false positives).
It does this by looking for discriminating characteristics of the attack traffic such as TCP flags, TTL ranges, ports and protocols, fragmentation, etc.