Q1 Average DDoS Attack - 1.8 (Arbor) or 48 Gbps (Prolexic)?

 
Few days ago Prolexic reported that ".. average attack bandwidth totaled 48.25 Gbps in Q1 2013, a 718 percent increase over last quarter" (here) - indeed an amazing number, far beyond the capacity of almost any enterprise connection  and a real threat to many ISPs.

Arbor Networks shows a significantly lower numbers. While the average attack volume also shows a nice growth (+19.5%), it reaches just 1.77 Gbps (see chart below for peak attack size). Not only the number and growth rate make more sense, it is also a more reasonable use of resources by those who try to attack even the bigger enterprises.

Arbor says that ".. attacks above 10 and even 20Gb/sec now occur multiple times per day somewhere in the world. Every day hundreds, or even thousands, of attacks take place utilizing different attack vectors, having different levels of complexity and different motivations and resources behind them. For enterprise network operators, it is important to have a broad view of what is going on out there .. Proportion of attacks in the 2 – 10Gb/sec range grows from 15% to 21.5%" 

See "Q1 Key Findings from ATLAS" -here.