Having peered into various crystal balls, Cisco figures global Internet traffic will grow 46% a year between now and 2012, nearly doubling every two years.

The projection translates into an annual bandwidth demand of more than a half a zettabyte, the equivalent of at least 125 billion DVDs, largely because of online video and social networking.

Cisco says video-on-demand, IPTV, P2P video and Internet video will represent ~90% of all consumer traffic in 2012.

Business traffic should be up 35% a year between now and 2012, growing fastest in the developing markets but North America will still lead in volume followed by Asia-Pacific and Western Europe.

Mobile data traffic is supposed to roughly double each year for the next five years.